COMPARATIVE EVALUATION OF DIFFERENT ENDODONTIC …

i

COMPARATIVE EVALUATION OF DIFFERENT ENDODONTIC IRRIGANTS

ON SMEAR LAYER AND MICROHARDNESS OF DENTIN – AN IN VITRO

STUDY

By

Dr. AMBILI C

Dissertation Submitted to the

Rajiv Gandhi University of Health Sciences, Karnataka, Bengaluru

In partial fulfillment

of the requirements for the degree of

Master of Dental Surgery

In

Conservative Dentistry and Endodontics

Under the guidance of

Dr.B. S. KESHAVA PRASAD

Professor and Head

Department of Conservative Dentistry and Endodontics

D. A Pandu Memorial R. V. Dental College and Hospital

Bengaluru

2017-2020

Scanned with CamScanner

viii

LIST OF ABBREVIATIONS

ADA- American Dental Association

ANOVA- Analysis Of Variance

CHX- Chlorhexidine Gluconate

EDTA – Ethylene di-amine tetra acetic acid

Fig- Figure

gf- Gram force

ISO- International Organization for Standardization

mm- Millimeter

min- Minute

μm- Micrometers

MCJ-Morinda Citrifolia juice

NaOCl-Sodium hypochlorite

n- Number of samples

p-value- Probability value

SD- Standard deviation

VHN- Vickers Hardness number

ix

LIST OF TABLES AND GRAPHS

SL.NO.

TABLE NO/

GRAPH NO.

TABLES AND GRAPHS

PAGE.

NO.

1.

Table :1

Advantages and disadvantages of currently used

irrigants

8

2.

Table :2

Comparison of mean smear layer removal scores

between irrigants by krukal walli’s test

51

3.

Table : 3

Multiple comparison of mean smear layer

removal scores between different irrigants by

tukey’s post –hoc test.

52

4.

Table : 4

Comparison of mean microhardness value

between different groups before immersing in

irrigants by one-way ANOVA TEST

53

5.

Table : 5

Comparison of mean dentin microhardness value

between different groups after immersing in

irrigants using one-way ANOVA test

53

6.

Table : 6

Multiple comparison of mean dentin

microhardness between the groups after

immersing in irrigants using one-way ANOVA

test.

54

7.

Table : 7

Comparison of mean dentin microhardness

before and after immersing in irrigants using

kruskal walli’s test.

55

8.

Graph : 1

Mean smear layer removal scores between

different irrigants

87

9.

Graph : 2

Mean dentin microhardness value between

different groups before immersing in irrigants.

87

10.

Graph : 3

Mean dentin microhardness value between

different groups after immersing in irrigants

88

11.

Graph : 4

Mean dentin microhardness before and after

immersing in irrigants in each group.

88

xi

LIST OF FIGURES

SL.NO.

FIGURE

NO.

TITLE

PAGE

NO.

1 Figure -1 Human mandibular teeth used in the study 82

2 Figure -2 Decoronation of sample 82

3 Figure -3 Decoronated sample 83

4 Figure -4 Armamentarium used 83

5 Figure -5 Irrigants used 84

6 Figure -6 Access opening 84

7 Figure -7 Cleaning and shaping 84

8 Figure -8 Final irrigants used for 3 minutes 85

9 Figure -9 Sectioning of sample 85

10 Figure -10 Sectioned sample 85

11 Figure -11 Specimens observed under stereomicroscope 86

12 Figure -12 Sectioning of sample for microhardness 87

13 Figure -13 Sectioned sample 87

14 Figure -14 Vertical section of root embedded in resin 87

15 Figure -15 Samples embedded in autopolymerising

resin 88

16 Figure -16 Polishing of the root specimens 88

17 Figure -17 Immersion of specimens in test solution for

5 minutes 89

18 Figure -18 Vicker’s microhardness tester 90

19 Figure -19 Evaluation of microhardness 90

20 Figure -20 3 % Sodium hypochlorite 95

21 Figure -21 6% morinda citrifolia juice 95

22 Figure -22 2% chlorhexidine 96

23 Figure -23 Normal saline 96

Structured abstract

xiii

STRUCTURED ABSTRACT

Title:

Comparative evaluation of different endodontic irrigants on smear layer and

microhardness of dentin – an in vitro study.

Back ground and Objective:

The purpose of present study was to evaluate the effect of 3% Sodium hypochlorite

(NaOCl), 6% Morinda citrifolia juice (MCJ) ,2% Chlorhexidine gluconate (CHX) and

saline on smear layer and microhardness of root canal dentin.

Methods:

Eighty extracted human mandibular premolars were selected and decoronated. All the

root specimens were cleaned and shaped with k-file in conjugation with distilled water

and divided in to 2 sections of 40 specimens each. For evaluation of smear layer, 40

samples were finally irrigated with 4 groups of test irrigants. Group 1: 3% NaOCl,

Group 2: 6% MCJ, Group 3: 2% CHX, Group 4: Saline .The specimens were

longitudnally sectioned and observed under stereomicroscope. For microhardness

evaluation, the other 40 specimens were sectioned longitudinally into 2 parts and

embedded in auto polymerizing resin. The mounted specimens were grounded smooth

and polished. Samples were placed in test irrigants and subjected to microhardness

testing. One way ANOVA and post hoc Tukey’s tests were used to reveal any significant

differences among and between groups respectively

Structured abstract

xiv

Results:

For smear layer removal , Group 1 showed best results at time interval of 3 minutes

followed by Group 2, Group 3 and Group 4 being ineffective , with statistically

significant difference (p<0.001). For dentin microhardness, Group 1 performed slightly

better than Group 2 followed by Group 3 and Group 4. The difference was found to be

statistically significant.

Conclusion:

It can be concluded from the present study that MCJ is effective in smear layer removal

compared to NaOCl with little reduction in microhardness of dentin which is a serious

concern in case of other endodontic solutions.

Key words: microhardness, NaOCl, MCJ, CHX, Vicker’s tester, analytical

microbalance.

Introduction

1

INTRODUCTION

Endodontic treatment essentially aim towards the prevention and control of pulpal and

periradicular infections. The outcome of endodontic therapy depends on many factors

like method and quality of instrumentation irrigation, disinfection and three dimensional

obturation of the root canal. Complete chemomechanical preparation may be considered

as an important step in root canal disinfection 1. The dental root canal is close to some of

the most heavily bacterially contaminated sites in the body. It is extremely likely that a

diverse range of species reach the root canal and surrounding dentine2.

The major causes of pulpal and periapical diseases are living and non living irritants. The

latter group includes mechanical, thermal and chemical irritants. The living irritants

include diverse microorganisms like bacteria, yeasts and viruses. When pathological

changes occur in the dental pulp, the root canal space gain the ability to harbor various

irritants including several species of bacteria, along with their toxins and byproducts3.

Once the root canal is infected coronally, infection advances apically until bacterial

products or bacteria themselves are in a position to stimulate the periapical tissues,

thereby causing apical periodontitis. Endodontic infections have a polymicrobial nature,

with obligate anaerobic bacteria conspicuously dominating the microbiota in primary

infections4.

Introduction

2

Infection of a dental root canal is predisposed by physical damage to a tooth and by

failure in immunological response to microbial invaders. Possible sources of infection

are2:

“ Trauma leading to fracture

“ Dental caries leading to access to tubules

“ Periodontal disease leading to access to tubules

“ Tooth erosion, attrition, abrasion

“ Microleakage of restorations

“ Operative procedures

Bacteremia

Elimination of microorganisms from infected root canals is a difficult task. Numerous

measures have been described to reduce the numbers of root canal microorganisms,

including the use of various instrumentation techniques, irrigation regimens and intra-

canal medicaments5

Disinfecting and cleaning the root canal system of microbial flora and pulpal tissue are

essential for successful root canal treatment. The root canal system is complex, and

canals may branch and divide6. Biomechanical preparation is the stage of endodontic

treatment that targets at cleaning, disinfecting and shaping the root canals in order to

eradicate bacteria and their irritating products, degenerated pulp tissue and contaminated

dentin, thereby creating an adequate surgical space for filling the root canal system7.

Although, cleaning and shaping reduce microorganisms, the use of irrigants is

Introduction

3

complimentary to instrumentation in facilitating their removal. Several chemicals and

therapeutic agents are used to accomplish this goal8

Whenever dentine is cut using hand or rotary instruments, the mineralized tissues are not

shredded or cleaved but shattered to produce considerable quantities of debris. Much of

this is made up of very small particles of mineralized collagen matrix, is spread over the

surface to form what is called the smear layer9. Identification of the smear layer was

made possible using the electron microprobe with scanning electron microscope (SEM)

attachment, and first reported by Eick et al (1970). These workers showed that the smear

layer was made of particles ranging in size from less than 0.5–15 μm.They are

approximately 2–5 μm thick, extending a few micrometres into the dentinal tubules9. The

first researchers to describe the smear layer on the surface of instrumented root canals

were McComb & Smith (1975). In support of its removal are;

It has an unpredictable thickness and volume, because a great portion of it consists of

water.

It contains bacteria, their by-products and necrotic tissue. Bacteria may survive and

multiply and can proliferate into the dentinal tubules 1990), which may serve as a

reservoir of microbial irritants.

Bacteria may be found deep within dentinal tubules and smear layer may block the

effects of disinfectants in them.

It can act as a barrier between filling materials and the canal wall and therefore

compromise the formation of a satisfactory seal.

It is a loosely adherent structure and a potential avenue for leakage and bacterial

contaminant passage between the root canal filling and the dentinal walls.

Introduction

4

Conversely, some investigators believe in retaining the smear layer during canal

preparation, reasons;

It can block the dentinal tubules, preventing the exchange of bacteria and other irritants

by altering permeability.

The smear layer serves as a barrier to prevent bacterial migration into the dentinal

tubules9.

Irrigation plays an important role in removal of tissue remnants and debris from the

complicated structure of root canal anatomy5. Therefore, there is a need to supplement

mechanical preparation with chemicals which can dissolve the tissue remnants and

disinfect the canal system. The mechanical action of instruments and chemical effect of

irrigants occur concurrently, referred to as chemomechanical preparation6.

Ideal properties of an irrigant;

To effectively clean and disinfect the root canal system, and offer long-term antibacterial

effect (substantivity),

Remove the smear layer,

Nonantigenic,

Nontoxic

Noncarcinogenic.

It should have no adverse effects on dentin or the sealing ability of filling materials.

It should be relatively inexpensive, convenient to apply and cause no tooth discoloration.

Introduction

5

An ideal irrigant include the ability to dissolve pulp tissue and inactivate endotoxins3

No irrigant can completely eradicate all organic and inorganic matter and at the same

time impart a substantive residual antimicrobial property to the canal wall dentin. It

should be also active against the Enterococcus faecalis, thus the combination of auxiliary

solutions is necessary to achieve the desired effects10

.

The irrigants that are currently used during cleaning and shaping can be divided into

antibacterial and decalcifying agents or their combinations. They include sodium

hypochlorite (NaOCl), chlorhexidine, ethylenediaminetetraacetic acid (EDTA), and a

mixture of tetracycline, an acid and a detergent (MTAD)3

SODIUM HYPOCHLORITE (NaOCl).

Sodium hypochlorite (NaOCl) is the most commonly used irrigating solution having an

inherent tissue dissolving capacity. It was first used by Henry Drysdale Dakin and Alexis

Carrel during World War I for irrigation of infected wounds. Subsequently in early

1920’s aqueous solution of NaOCl was used in higher concentration for endodontic usage

and is used in concentrations varying from 0.5% to 5.25%11

. The most effective irrigation

regimen is reported to be 5.25% at 40 min. NaOCl was moderately effective against

bacteria but less effective against endotoxins in root canal infection11

. The tissue

dissolution property of NaOCl is due to the presence of their free available chlorine in the

solution12

. For effective removal of both organic and inorganic components of the smear

layer, it is recommended to use 2.5–6% NaOCl during root canal therapy followed by

17% EDTA13

.

Introduction

6

The advantages of using NaOCl as an irrigant includes mechanical cleaning of debris of

canal, capacity of dissolving vital and necrotic tissues, anti-microbial activity and long

shelf life. Disadvantages of NaOCl are its inability to remove smear layer, toxicity, and

severe inflammatory reaction12

MORINDA CITROFOLIA JUICE

In the recent years attention has been diverted toward the search for the new novel

compounds from plants, animals and microbes. Due to the increasing trend of multidrug

resistance the study has been concentrated on newer antimicrobial compounds of plant

origin. A number of plants have been identified with the properties of antimicrobial

activity. Research has also been carried out on various aspects of M. citrifolia L. Herbal

irrigation solutions are generally considered as safe and nontoxic for the host and some

have proved to be strong antibacterial materials in vitro14

.

Morinda citrifolia (MCJ) has a broad range of therapeutic effects, including antibacterial,

antiviral, antifungal, antitumor, antihelmintic, analgesic, hypotensive, antiinflammatory,

and immune-enhancing effects. MCJ contains the antibacterial compound L-asperuloside

and alizarin. Murray et al proved that, as an intracanal irrigant to remove the smear layer,

the efficacy of 6% MJC was similar to that of 6% NaOCl in conjunction with EDTA. The

use of MCJ as an irrigant might be advantageous because it is a biocompatible

antioxidant and not likely to cause severe injuries to patients as might occur through

NaOCl accidents11

.

Introduction

7

CHLORHEXIDINE GLUCONATE

According to Tomás et al., back in 1947, a complex study to synthesize new antimalarial

agents led to the development of the polybiguanides. These compounds showed powerful

antimicrobial potential, particularly compound 10,040, a cationic detergent later called

chlorhexidine. The first salt derived from compound 10,040 that reached the market was

chlorhexidine gluconate15

.

Chlorhexidine gluconate has been used for the past 50 years for caries prevention, in

periodontal therapy and as an oral antiseptic mouth wash Chlorhexidine gluconate (CHX)

is a mouth wash that is used in different densities as a detergent for endodontic

treatment16

. It has a broad-spectrum antibacterial action, sustained action and low

toxicity. This material has low toxic property and it is absorbed by dental tissue and

mucous membrane, while its active material is released slowly.

Biocompatibility property and substantivity of CHX justifies clinical use of this material

(Because of these properties, it has also been recommended as a potential root canal

irrigant16

. The major advantages of chlorhexidine over NaOCl are its lower cytotoxicity

and lack of foul smell and bad taste. However, unlike NaOCl, it cannot dissolve organic

substances and necrotic tissues present in the root canal system. In addition, like NaOCl,

it cannot kill all bacteria and cannot remove the smear layer and it can discolour teeth.

Normal saline is an isotonic solution to the body fluids and is being commonly used as an

irrigating material in all the surgical procedures. Endodontic treatment is also a type of

surgical procedure, so normal saline is frequently used here17

.

Introduction

8

Table- 1: Advantages and disadvantages of currently used intracanal irrigants

CHARACTERISTICS

MTAD

NaOCl

CHX

EDTA

Shelf life stability

+

_

+

+

Antimicrobial activity

+

+

+

_

Ability to remove smear layer

+

_

_

+

Biocompatibility

+

_

+

+

Ability to dissolve pulp tissue

+

+

_

+/-

Dentin conditioning properties

+

_

_

+

Positive effect on root canal seal

+

_

_

+/-

Negative effect on dentin structure

_

+

_

+

Upregulation of immune response

+

_

_

_

Application time (minutes)

519

4022

?

131

Some investigations have acclaimed that canal irrigants are capable of altering the

chemical composition of human dentin and changing the calcium/phosphorus (Ca/P) ratio

Introduction

9

of the dentin surface. Microhardness determination can provide indirect evidence for

losing or gaining any mineral substance in the dental hard tissues13

. During smear layer

removal, irrigation materials cause alterations in the chemical composition of dentine,

which may result in microhardness decrease and erosion. A reduction in microhardness

facilitates the instrumentation throughout the root canal. However, when it becomes

substantial, it may also weaken the root structure.

To evaluate microhardness changes in root canal dentin, Vicker’s hardness and Knoop

hardness testing can be used. Selection of Vicker’s microhardness tester over Knoop

hardness tester in our study was due to the suitability and practicality of Vicker’s test for

evaluating surface changes of deeper dental hard tissues. Knoop hardness tester is used

for superficial dentine rather than for deep dentin18

.

A similar correlation can be made between microhardness and roughness of root dentin

and irrigating solutions. Thus, it is of interest to investigate to what extent the dentin of

root canal is affected by the use of various irrigating solutions19

.

Therefore, the aim of this in vitro study is to compare and evaluate the effect of different

endodontic irrigants on smear layer and microhardness of dentin.

Objectives

10

OBJECTIVES

1. To assess and compare smear layer removal capacities of 3% Sodium hypochlorite,

6% Morinda Citrifolia Juice, 2% Chlorheridine Gluconate , irrigating solutions and

normal saline.

2. To evaluate and compare the dentine microhardness changes using these four test

irrigating solutions.

Review of literature

11

REVIEW OF LITERATURE

An in-vitro study was conducted to evaluate the efficacy and the working time required

for three endodontic irrigating solutions for removal of smear layer. 10 freshly extracted

maxillary central incisors were chosen for the study. Access cavity preparation was done

and instrumented till #70 K-file with irrigation with saline solution. The teeth were

decoronated and sectioned longitudinally to obtain 40 samples. Samples were divided

into four groups: 1) EDTA, 2) NaOCl, 3) EDTA+NaOCl, 4) Saline. The samples were

treated with the test irrigants for 30 minutes and subjected for SEM analysis. Results

showed that at 30 minutes working time, almost all debris was cleared in group 1. In

group 2, at 30 minutes working time also most of the smear layer was present covering

the dentin. When EDTA and NaOCl were used as a combination, in group 3 showed

almost all debris removal with clear dentinal tubules. Hence, it was concluded that EDTA

removed smear layer in 30 minutes and also demineralised the dentin matrix, the effect of

NaOCl alone on smear layer was not significant and that the combination of EDTA and

NaOCl was beneficial as it removed the smear layer in 20 minutes without affecting the

dentin surface20

.

The choice of an irrigating solution for use in infected root canals requires thorough

knowledge of the microorganisms responsible for the infectious process as well as the

properties of different irrigating solutions. Complex internal anatomy, host defenses and

microorganism virulence are important factors in the treatment of teeth with

asymptomatic apical periodontitis. Irrigating solutions must have expressive

antimicrobial action and tissue dissolution capacity. Sodium hypochlorite is the most


12

commonly used irrigating solution in endodontics, because of its mechanism of action

which causes biosynthetic alterations in cellular metabolism and phospholipid

destruction, formation of chloramines that interfere in cellular metabolism, oxidative

action with irreversible enzymatic inactivation in bacteria, and lipid and fatty acid

degradation. This review article discusses the mechanism of action of sodium

hypochlorite based on its antimicrobial and physico-chemical properties21

.

Sodium hypochlorite (NaOCl) has been advised for irrigation during root canal

preparation. The study used scanning electron microscopy to examine instrumented and

uninstrumented surfaces in the middle third of root canals following the use of different

concentrations of NaOCI (5.25%, 2.5%, 1.0%, and 0~.5%). NaOCI was delivered with

either an endodontic irrigation needle or an ultrasonic device. All the concentrations of

NaOCI with either delivery system were very effective in flushing the loose debris from

the root canals. A smear layer with some exposed dentinal tubules was seen on all

instrumented surfaces regardless of concentration of NaOCI or irrigation device. NaOCI

in concentrations of 5.25%, 2.5%, and 1% completely removed pulpal remnants and

predentin from the uninstrumented surfaces. Although 0.5% NaOCI removed the

majority of pulpal remnants and predentin from the uninstrumented surfaces, it left some

fibrils on the surface22

.

An in vitro comparative study was done to evaluate smear layer removal efficacy of

different irrigating solutions using scanning electron microscope. Freshly extracted

seventy-five single rooted permanent maxillary central incisor teeth with mature root

apices ,without any anatomic variation and patent root canal were subjected to

standardized root canal instrumentation (crown down technique). The working length


13

was determined with size of No #10K or No #15K stainless steel Files . All teeth were

instrumented using Hand Protaper files in sequence till F3. After instrumentation, all

teeth were divided into five groups according to final irrigation protocol Group (1)

Normal saline (n = 15) Group (2) 2.5% NaOCl (n = 15) Group (3) 17% EDTA + 2.5%

NaOCl (n = 15) Group (4) 10% citric acid + 2.5% NaOCl (n = 15) Group (5) 1.0%

tetracycline HCL + 2.5% NaOCl (n = 15). After final irrigation, the teeth were prepared

for scanning electron microscope analysis to evaluate the cleaning of apical third of

radicular dentine to determine the presence or absence of smear layer. In Group A

(control group) and Group B, where normal physiological saline and 2.5% NaOCl

respectively were used as an irrigants, the dentinal tubules were completely covered by

the smear layer under SEM typical appearance of smear layer could be seen on root canal

wall in apical third region. In Group C, a combination of 17% EDTA and 2.5% NaOCl

were used as irrigants. It was found that there was incomplete removal of smear layer in

the apical third area under SEM. The results obtained in this Group D (10% citric acid

and 2.5% NaOCl) were similar to the results obtained in Group C. Group E , where 1%

tetracycline HCl was used as an irrigant, the result was almost similar to Group C and

Group D. Although it showed that tetracycline HCl solution was effective as smear layer

removal, it was not able to remove it completely. The study concluded that irrigating

agents, citric acid and tetracycline HCl can be used as an alternative to EDTA for the

removal of smear layer in endodontics23

.

Chelating agents were introduced into endodontics as an aid for the preparation of narrow

and calcified canals in 1957 by Nygaard-Ostby. A liquid solution of

ethylenediaminetetraacetic acid (EDTA) was thought to chemically soften the root canal


14

dentin and dissolve the smear layer, as well as to increase dentin permeability. Although

the efficacy of EDTA preparation in softening dentin has been debated, chelator

preparations have regained popularity recently. A final irrigation of the root canal with

15-17% EDTA solutions dissolves the smear layer. In literature on chelating agents, these

reviews the chemical and pharmacological properties of EDTA preparations are

analyzed24

.

A Scanning electromicroscopic study was carried out to evaluate the cleaning qualities

and smear layer removal ability after irrigation with four different irrigating solutions. 50

extracted teeth were decoronated and instrumented up to 45 K-files. During the root

canal preparation, they were irrigated with the test solutions being evaluated: Group 1-

2.5% NaOCl, Group 2- 2.5% NaOCl+17% EDTA, Group 3-2% CHX, Group 4-

2%CHX+17%EDTA, group 5-Saline, Group 6- Saline+17%EDTA. The roots were

sectioned for SEM analysis at cervical, middle and apical third. Results showed that the

use of 17% EDTA decreased the smear layer significantly for all the evaluated solutions

in all thirds. When EDTA was not used, a significantly higher quantity of smear layer on

the apical third was observed only in the NaOCl groups. The use of 17% EDTA was

significant for debris removal except for the CHX groups. Hence, the authors concluded

that the use of EDTA was necessary to enhance cleanness of the root canals25

.

The main objective in root canal treatment is to disinfect the entire root canal system.

This requires that the pulpal contents be removed as sources of infection. This goal may

be accomplished using mechanical instrumentation and chemical irrigation, along with

medication of the root canal between treatment sessions. Microorganisms and their by-

products are considered to be the major cause of pulpal and periradicular pathologies . In


15

order to reduce or eliminate bacteria and pulpal tissue remnants, various irrigation

solutions have been suggested to be used during treatment. Sodium hypochlorite, an

excellent non-specific proteolytic and antimicrobial agent, is the most common irrigation

solution used during root canal therapy. The purpose of this paper was to review different

aspects of sodium hypochlorite use in endodontics26

.

This invitro study assessed the necrotic tissue dissolution capacity of some popular and

some potential root-canal irrigants: 1% (wt/vol) sodium hypochlorite (NaOCl), 10%

chlorhexidine, 3% and 30% hydrogen peroxide, 10% peracetic acid, 5%

dichloroisocyanurate (NaDCC), and 10% citric acid. Necrotic soft-tissue remnants in root

canals may provide a source of nutrition for surviving microbiota after root-canal

therapy. The study concluded that only NaOCl had any substatntial tissue dissolution

capacity. The tissue-dissolution capacity of hypochlorite formulations is a direct function

of their free available chlorine (OCl- /HOCl) in solution. It has been demonstrated that at

the same levels of “free” chlorine, aqueous NaOCl is a far better bactericide than

NaDCC. This is because of the higher redox potential of NaOCl, i.e. the fact that a major

part of the “free” chlorine in NaDCC formulations is not reactive27

.

A successful root canal therapy is largely dependent on thorough chemomechanical

debridement of the root canal space. This results in the formation of an amorphous layer

called smear layer. The aim of this study was to compare the in vitro effectiveness of two

potential herbal irrigants: 6% German chamomile extract (GCE) and 6% Morinda

citrifolia juice (MCJ), in removal of smear layer. Eighty single rooted human teeth were

allocated into two equal groups: one to be instrumented with the self‑adjusting file (SAF),

while the other with WaveOne (WO). Four subgroups in each group were irrigated with


16

6% GCE, 6% MCJ, 17% ethylenediaminetetraacetic acid (EDTA) (positive control), and

NS (negative control). Scanning electron microscopy (SEM) was used to evaluate the

presence of smear layer. The most effective smear layer removal in the coronal part was

observed with SAF‑EDTA and SAF‑GCE, followed by WO‑EDTA. In the middle part,

SAF‑GCE was equivalent to that of SAF‑EDTA, followed by WO‑EDTA and WO‑GCE.

In the apical third, the most efficient smear layer removal was observed with

SAF‑EDTA, followed by some removal of smear layer by WO‑EDTA and SAF‑GCE.

GCE was as effective as EDTA in removal of smear layer in the coronal and mid‑root

regions, when used with continuous irrigation. MCJ 6% was ineffective in removal of

smear layer, with either irrigation method. GCE 6% did not cause the excessive

demineralization that was observed with 17% EDTA28

.

Successful endodontic therapy needs shaping and cleaning of root canal systems. Smear

layer is produced during root canal preparation by the manipulation of the dental canal

walls. It is believed that the presence of smear layer contributes to leakage, and it is a

source of nutrients for microorganisms. The aim of this study was to evaluate the effect

of Morinda Citrifolia Juice (MCJ) on smear layer removal and microhardness value of

root canal dentin in compared with various endodontic irrigants. 84 single-rooted human

teeth were prepared to apical size of #35. After decoronation, samples were divided into

seven groups of 12 in each (n = 12). Specimens were finally irrigated by either 1: 2.5%

NaOCl, 2: 6% MCJ, followed by a final flush of 17% ethylenediaminetetraacetic acid

(EDTA), 3: 6% MCJ, 4: 2.5% NaOCl then17% EDTA, 5: MTAD, 6: 2% chlorhexidine

(CHX), and 7: saline. After irrigation, all samples were subjected to Vickers

microhardness test at 100 and 500-μm depths and then were examined under scanning


17

electron microscopy (SEM) and ImageJ program was used to calculate open dentinal

tubules. The microhardness values at 100 μm and 500 μm for MTAD were significantly

lower than for NaOCl + EDTA and MCJ + EDTA groups (p < 0.05). MCJ + EDTA,

NaOCl + EDTA, and MTAD protocol significantly removed smear layer. It was

concluded that 6% MCJ followed by a final flush of 17% EDTA can be regarded as an

effective solution on smear layer removal29

.

Microorganisms and their by‑products are considered to be the major cause of pulp and

periradicular pathosis. The aim of this in vitro study was intended to compare and to

evaluate the antimicrobial efficacy of Morinda citrifolia juice (MCJ) with chlorhexidine

(CHX) as endodontic irrigants and their effect on micro hardness of root canal dentin.

The samples were divided into two parts. Part I for antibacterial testing consisted of

preparing 60 dentin blocks of 4 mm height. All the dentin blocks were infected with

Enterococcus fecalis for a period of 21 days. The four groups were Group I: 0.2% CHX;

Group II: 6% MCJ; Group III: 6% MCJ + 0.2% CHX; Group IV: Saline, the dentin

shavings from root canal dentin was harvested and colony forming units counted after 28

days of medication. Part II for micro-hardness testing consisted of preparing 32 root

halves and mounting them on blocks of acrylic resin. The experimental samples were

divided in to 8 samples per group. The samples were then medicated with the irrigants for

a period of 15 min and micro-hardness values were recorded. 0.2% CHX showed the

maximum antibacterial activity against E. fecalis used as test organism after 28 days. 6%

MCJ showed some antibacterial activity but to a lesser extent than CHX after 28 days.

None of the irrigants affected the micro‑hardness of root canal dentin14.


18

An in vivo study was done to assess the antimicrobial efficacy of 6% Morinda citrifolia,

Azadirachta indica, and 3% sodium hypochlorite as root canal irrigants. Thirty non-vital

maxillary anteriors were randomly assigned to one of the three groups corresponding to

the irrigant to be tested; the sample groups are 6% Morinda citrifolia juice (MCJ) (n =

10), A. indica (n = 10) and 3% NaOCl (n = 10). After access opening a root canal culture

sample was taken with two paper points and cultured under aerobic and anaerobic

conditions. Cleaning and shaping were completed with irrigation by 10 ml of respective

irrigants and 5 ml of final rinse. The patients were called after 3 days and canals were

irrigated again with 5 ml of the test irrigants. This was followed by obtaining a post

treatment root canal culture sample and culturing and analyzed by counting the colony

forming units. All the samples showed a significant reduction (P < 0.05) in the mean

CFU counts for aerobic and anaerobic bacteria between baseline and 3 days. There was

no difference in the antimicrobial efficacy of 6% M. citrifolia, A. indica, and 3% NaOCl

as root canal irrigants6.

An in vitro study was done to evaluate the antibacterial activity of conventional and

experimental endodontic irrigants against E. faecalis. The substances were evaluated by

direct contact test: 2.5% sodium hypochlorite (NaOCl); 2% chlorhexidine (CHX); 1%

peracetic acid. After different contact periods (30 s, 1, 3, and 10 min), a neutralizing

agent was applied. Serial 10-fold dilutions were prepared and plated onto tryptic soy agar

(TSA) and the number of colony-units per milliliter (CFU/ml) was determined. Sterile

saline was used as a negative control. Results revealed that both 2.5% NaOCl and 2%

CHX eliminated E. faecalis after 30 s of contact. Peracetic acid reduced the bacterial

counts by 86% after 3 min and completely eliminated E. faecalis after 10 min.


19

Researchers concluded that 1% peracetic acid is effective against E. faecalis, despite its

slower action compared with 2.5% NaOCl and 2% CHX30

.

A study was conducted to determine the ability to dissolve bovine pulp tissue by

photodynamic therapy. Twenty pieces of bovine pulp tissue were weighed and divided

randomly into four groups (n=5): G1 – distilled water (negative control), G2 – sodium

hypochlorite 1% (positive control), G3 – photodynamic therapy, G4 – sodium

hypochlorite 1% + photodynamic therapy. The observation of dissolution was performed

by two observers blinded in relation to the test, recording the time in minutes until

complete tissue dissolution. The total observation time was 2 hours. The dissolution rate

was calculated dividing the weight of the fragment pulp (mg) by the time of dissolution

(mg/min). Results showed that only group 2 (NaOCl) was able to promote complete

dissolution of pulp tissue. In the other groups there was no occurrence of complete

dissolution31

.

An in vitro study was carried out to evaluate the efficiency of different endodontic

irrigants in the removal of smear layer through scanning electron microscopic image

analysis. The smear layer consists of both organic and inorganic substances such as

fragments of odontoblastic processes, microorganisms, and necrotic material covering the

root canal walls and openings of the dentinal tubules. The smear layer itself may be

infected and may protect the bacteria within the dentinal tubules. 45 single-rooted

extracted human mandibular premolar teeth with single canal and complete root

formation were taken for the study.. Teeth were randomly assigned to three groups with

15 teeth in each group. Group I samples were irrigated with 17% ethylenedi-

aminetetraacetic (EDTA) irrigation, Group II with 7% maleic acid irrigation, and Group


20

III with 2% Chlorhexidine irrigation. Scanning electron microscope evaluation was

done for the assessment of smear layer removal in the coronal, middle, and apical thirds.

The most efficient smear layer removal was seen in Group I with 17% EDTA irrigation

compared with other groups (P < 0.05) and the least by 2% chlorhexidine. The present

study concluded that 17% EDTA efficiently removes the smear layer from root canal

walls32

.

The complex root canal system precludes the absolute elimination of the bacteria.

Facultative bacteria such as enterococci, nonmutans streptococci, and lactobacilli are

more probable to endure chemo-mechanical instrumentation and irrigation medication.

An in vitro study was done to evaluate the efficiency in removal of smear layer of

mixture of tetracycline, acid and detergent (MTAD), sodium hypochlorite (NaOCl),

ethylenedi-aminetetraacetic acid (EDTA) and chlorhexidine gluconate by scanning

electron microscope (SEM) evaluation and also to evaluate the antimicrobial action of the

same irrigants against standard culture strains of Enterococcus faecalis. 60 extracted

permanent teeth with single root canal were taken for the study. The sample was divided

into five groups with 12 teeth in each group. Root canals were enlarged till size 40 with

K-files. One group was kept as control and irrigated only with saline. Other four groups

used 5% NaOCl as irrigant during instrumentation and MTAD, 5% NaOCl, 17% EDTA,

and 2% chlorhexidine gluconate as final rinse. Teeth were split and examined under

SEM. To test the antibacterial action, the zone of inhibition method using agar plates was

used. The results showed mean zone of inhibition formed by the irrigants was in the

following order; MTAD (40.5 mm), 2% chlorhexidine gluconate (29.375 mm), 17%

EDTA (24.125 mm), 5% NaOCl (22.125 mm), and saline (zero). The study concluded


21

that MTAD showed high smear layer removal efficacy, but no significant difference was

found to that of 17% EDTA. As the dimensions of the zones of inhibition showed,

MTAD has got highest antibacterial action against E. faecalis, followed by 2% CHX,

17% EDTA, and 5% NaOCl33

.

During canal preparation, dentine chips created by the action of endodontic instruments

add to the remnants of organic material and irrigating solutions, forming a smear layer

that adheres to the canal walls. This layer can form two zones: the first, 1–2 μm-thick,

made up of organic matter and dentine particles; the second, extending into dentinal

tubules to a depth of 40 μm (smear plugs) is formed largely of dentine chips. An in vitro

study was done, under the scanning electron microscope (SEM),to verify the influence of

irrigation time with ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite

(NaOCl) on intracanal smear layer removal. The study used 21 extracted human

permanent teeth with single straight root canals. The root canals of the teeth were

instrumented and, at the end of preparation, were irrigated with 3 ml of 15% EDTA,

followed by 3 ml of 1% NaOCl for 1 min (group 1), for 3 min (group 2), and for 5 min

(group 3). The canals of teeth in group 4 (control) did not receive the final irrigation. The

teeth were sectioned longitudinally and prepared for an SEM. The dentinal wall of

cervical, middle and apical thirds was graded according to the amount of debris and

smear layer remaining on the walls the results of the study showed irrigation with EDTA

and NaOCl completely removed the smear layer from the cervical and middle thirds. The

study concluded that canal irrigation with EDTA and NaOCl for 1, 3 and 5 min were

equally effective in removing the smear layer from the canal walls of straight roots34

.


22

The major goal of endodontic therapy is to remove the pulpal debridement and bacterial

population from the root canal system. Because of the complex anatomy of root canals,

up to 50% of canal walls remain uninstrumented during preparation, resulting in

insufficient debridement. . The aim of this in vitro study was to compare organic tissue

dissolution capacity of NaOCl and ClO2. In this study, 5.25% NaOCl, 13.8% ClO2, and,

as a control, isotonic saline solutions (0.9% NaCl) were used. Thirty bovine pulp

specimens were previously weighed and immersed for 20 minutes in each test solution

(changing the solution every 2 minutes). The pulp specimens were then blotted dry and

weighed again. The results showed Both 5.25% NaOCl and 13.8% ClO2 dissolved the

tissue pieces more effectively than saline control . Within the limitations of this in vitro

study, it was concluded that ClO2 and NaOCl are equally efficient for dissolving organic

tissue35

.

Biomechanical preparation is the stage of endodontic treatment that aims at cleaning,

disinfecting and shaping the root canals in order to create an adequate surgical space for

filling the root canal system. This in vitro study evaluated the capacity of debris removal

from the apical third of flattened root canals, using different final irrigation protocols.

The study used 30 human mandibular central incisors with a mesio-distal flattened root.

The specimens were prepared using rotary instrumentation by Endo-Flare 25.12 and Hero

642 30.06, 35.02, 40.02 files, irrigated with 2 ml of 1% NaOCl after each file. The

specimens were randomly distributed into 5 groups according to the final irrigation of

root canals: Group I: 10 ml of distilled water (control), Group II: 10 ml of 1% NaOCl for

8 min, Group III: 2 ml of 1% NaOCl for 2 min (repeated 4 times), Group IV: 10 ml of

2.5% NaOCl for 8 min, and Group V: 10 ml of 2.5% NaOCl for 2 min (repeated 4 times).


23

The apical thirds of the specimens were subjected to histological processing and 6-µm

cross-sections were obtained and stained with hematoxylin-eosin. The specimens were

examined under optical microscopy at ×40 magnification. The results of the study is that

, comparative analysis between Group I (control) and Groups II, III, IV and V did not

show statistically significant difference . In conclusion, the final irrigation protocols

evaluated in this study using the Luer syringe presented similar performance in the

removal of debris from the apical third of flattened root canals.7

Irrigation plays an indispensable role in removal of tissue remnants and debris from the

complicated root canal system. The aim of this study was to compare the human pulp

tissue dissolution by different concentrations of chlorine dioxide, calcium hypochlorite

and sodium hypochlorite. Pulp tissue was standardized to a weight of 9 mg for each

sample. In all,60 samples obtained were divided into 6 groups according to the irrigating

solution used- 2.5% sodium hypochlorite (NaOCl), 5.25% NaOCl, 5% calcium

hypochlorite (Ca(OCl)2), 10% Ca(OCl)2, 5% chlorine dioxide (ClO2) and 13% ClO2. Pulp

tissue was placed in each test tube carrying irrigants of measured volume (5ml) according

to their specified subgroup time interval: 30 minutes (Subgroup A) and 60 minutes

(Subgroup B). The solution from each sample test tube was filtered and was left for

drying overnight. The residual weight was calculated by filtration method. Results

showed 5.25% NaOCl to be most effective at both time intervals followed by 2.5%

NaOCl at 60 minutes, 10% Ca(OCl)2 and 13% ClO2 at 60 minutes. Least amount of

tissue dissolving ability was demonstrated by 5% Ca(OCl)2 and 5% ClO2 at 30 minutes.

Distilled water showed no pulp tissue dissolution. Within the limitations of the study,


24

NaOCl most efficiently dissolved the pulp tissue at both concentrations and at both time

intervals5.

A successful endodontic treatment requires good shaping, removal of infected tissues,

and 3D obturation of the canal. The aim of the in vitro study was to evaluate the effect of

EDTA, sodium hypochlorite and chlorhexidine on dentin microhardness at the furcation

area of mandibular molars. 40 extracted human permanent mandibular molars were

selected for study. Access opening and instrumentation done till No.F2 hand protaper

files. Saline is used as an irrigant during cleaning & shaping. Teeth were randomly

subjected to 4 groups (n=10) according to the irrigating techniques as Group 1: Saline,

Group 2: ethylene di-aminetetraacetic acid (EDTA), Group 3: sodium hypochlorite,

Group 4: chlorhexidine. Irrigating solution were activated in the canals with manual

activation technique. Then teeth were sectioned longitudinally approximately 5 mm

below cementoenamel junction and embedded in acrylic resin block. Teeth were analyzed

for microhardness at furcation area with Knoop indenter. The result is the average dentin

microhardness at furcation area is significantly higher in teeth irrigated with

Chlorhexidine compared to EDTA, and sodium hypochlorite36

.

Endodontic therapy is primarily based on the removal of potentially noxious stimuli from

the complex root canal system. Sodium hypochlorite is used as an endodontic irrigant due

to its necrotic tissue dissolving capacity and antimicrobial properties. The purpose of this

study was to evaluate whether Chlorhexidine Gluconate (0.2%), when used as an

endodontic irrigant, would affect the seal obtained when using three different endodontic

sealers. One hundred human maxillary anterior single rooted teeth extracted for

periodontal reasons were used in this study The teeth were randomly divided into nine


25

experimental groups of ten teeth each, a positive and negative control group of five teeth

each. The root canals were instrumented in a step back manner using flexo-files and

Gates Glidden drills up to the working length to a master apical file size of #40. Teeth in

groups 1, 2, 3 were irrigated using sterile saline (0.9% sodium chloride), teeth in groups

4, 5, 6 were irrigated using 3% Sodium hypochlorite and teeth in group7, 8, and 9 were

irrigated using 0.2% Chlorhexidine Gluconate solution. In groups 1, 4 and 7 Zinc oxide

eugenol sealer was used, AH plus sealer was used in groups 2, 5, and 8, Metapex sealer

was used in-group 3, 6 and 9. All the tooth were obturated and access cavity was done

with Gic. The teeth were immersed in Methylene blue 2% for 2 days at 370 C. The

samples were then observed under Stereomicroscope. The result in the present study

showed that Chlorhexidine gluconate did not affect much of the apical seal as compared

to Sodium hypochlorite, saline and no difference in the sealing ability of sealers seen37

.

The aim of this in vitro studywas to compare the effectiveness smear layer removal in

root canals between the conventional method and with a new mechanical device. 30

extracted non-carious central incisors were used and divided equally into three groups.

Group A (n = 10) was used the control group and was not biomechanically prepared or

irrigated. Group B (n = 10) was cleaned and shaped using the conventional method with

rotary instruments and by irrigation with 5.25% sodium hypochlorite (NaOCl) and saline.

Group C (n = 10) was cleaned and shaped using a new mechanical device, a

microendobrush along with the conventional method of irrigation with 5% NaOCl and

saline. The teeth were split longitudinally into two halves and each half was divided into

three equal parts to obtain a pair of coronal, middle and apical third segment. The

specimens were mounted on clear acrylic and were evaluated under a profilometer


26

microscope and scanning electron microscope to view the surface roughness. The results

reveal that the newer method of irrigation with the microendobrush had better removal of

the smear layer and other debris. Based on the limitation of the study, the results reveal

that the newer method of chemo-mechanical preparation is more effective at smear layer

removal compared to the conventional method of chemo-mechanical preparation38

.

. An irrigant with the ability to remove the smear layer without causing erosion of the

radicular dentin and also eradicate microbial biofilms would be considered close to ideal.

The aim of this study was to compare the changes in microhardness of root dentin

caused by two novel irrigation regimens with conventional irrigation. Forty extracted

human permanent incisor teeth were selected. Decoronated specimens were embedded in

autopolymerizing acrylic resin and grounded flat with silicon carbide abrasive papers. Of

these, 60 root segments without any cracks or defects were selected and divided into four

groups according to the irrigation regimen used (n = 15). Group I: 5% sodium

hypochlorite (NaOCl) + 17% ethylene di-aminetetraacetic acid (EDTA) + 0.2%

chlorhexidine bigluconate (CHX) (conventional). Group II: 6% Morinda Citrifolia Juice

+ 17% EDTA (MCJ). Group III: 5% NaOCl + Q Mix 2 in 1 (QMix). Group IV: Distilled

water (control). Irrigation regimens were performed for 5 minutes. Results showed The

control group showed the least reduction in microhardness when comparison with the

other groups. Within the limitation of this study, it was concluded that NaOCl + Q Mix

were least detrimental to root dentin microhardness when compared with MCJ and

conventional irrigation regimens39

.

The effect of NaOCl, EDTA, etidronic (HEBP- hydroxyethylidene bisphophonate), and

citric


27

acid (CA) associated in different irrigation regimens on root dentin microhardness was

assessed.

Forty-five root halves of single-rooted teeth were sectioned into thirds that were

embedded in acrylic resin, polished, randomly assigned into 3 groups, and treated as

follows: G1: saline solution; G2: 5% NaOCl + 18% HEBP, mixed in equal parts; and G3:

2.5% NaOCl. After measurements, the G3 samples were distributed into subgroups G4,

G5, and G6, which were submitted to 17% EDTA, 10% CA and 9% HEBP, respectively.

Following the new measurements, these groups received a final flush with 2.5% NaOCl,

producing G7, G8, and G9. Microhardness was measured with Knoop indenter under a 25

g load for 15 seconds, before and after treatments. Except G1, all tested irrigation

regimens significantly decreased the microhardness. Results revealed that there were no

differences between root thirds before treatments, and all root thirds exhibited equal

responses to same treatment. Authors concluded that except saline, all tested irrigation

regimens reduced the root dentin microhardness40

.

The present procedures to disinfect the root canal system are primarily by means of

chemo-mechanical preparation. Despite that, only 60 to 80% or less of canal outlines can

be prepared circumferentially by instrumentation. Thus, the disinfection of the remaining

untouched area has to rely on chemical irrigation or intracanal medications. This study

investigated the ability of different irrigation protocols to keep dentinal tubules (DT)

open and avoid their blockage by the smear layer (SL) during the cleaning and shaping

procedure (CSP). Twenty-five extracted teeth were divided into five groups (n = 5):

group 1, NaOCl was kept in the canal during instrumentation and then washed out with

distilled water, and the canal was irrigated with NaOCl with EndoVac in between files;


28

group 2, the same procedure as group 1, but NaOCl was replaced by EDTA; group 3,

EDTA was kept in the canal during instrumentation and then washed out with distilled

water, and the canal was irrigated with NaOCl with EndoVac in between files; group 4,

the same as group 3, but NaOCl and EDTA were alternated; and group 5 (control), the

procedure was the same with group 1, but NaOCl was replaced by distilled water. A

scanning electron microscope was used to evaluate the cleanliness of DT at three

different levels of the canals. Groups 3 and 4 showed better ability to keep DT open

during CSP. The study concluded that alternating the use of NaOCl and EDTA with

water in between can keep DT open better and avoid their blockage by SL during CSP

compared with the use of NaOCl or EDTA alone41

.

Thorough debridement of root canals is essential to accomplish successful endodontic

treatment. However, it is impossible to create a sterile space in infected root canals with

mechanical preparation alone because of the complex anatomy of root canal systems.

The main objective of this study was to compare the efficacy of 5% NaOCl with 17%

EDTA, 18% Etidronic Acid, 9% Etidronic Acid and 0.2% Chitosan as different protocols

of irrigating solutions for smear layer removal using scanning electron microscope. Forty

extracted human teeth were collected for the study. Access opening followed by Bio-

mechanical Preparation was done and teeth were divided in to four groups and irrigated

as follows (n=10 per group).Group 1: 5% NaOCl during instrumentation, 17% EDTA

after instrumentation (3min),Group 2: 5% NaOCl during instrumentation, 9% Etidronic

acid after instrumentation (5min),Group 3: 5% NaOCl during instrumentation, 18%

Etidronic acid after instrumentation (3min),Group 4: 5% NaOCl during instrumentation,

0.2% Chitosan solution after instrumentation (5min).After the irrigation of specimens


29

longitudinal sectioning of specimens was done and subsequently smear layer removal

ability will be evaluated. The results of the study is that EDTA (Group 1) showed

comparatively better results than 9% Etidronic Acid (Group 2), 18% Etidronic Acid

(Group 3) and 0.2% Chitosan (Group 4) at the apical third. There is no significant

difference between 17% EDTA, 9% Etidronic Acid, 18% Etidronic Acid, and 0.2%

Chitosan in the ability to remove smear layer42

.

Success in endodontic therapy depends on chemo-mechanical debridement of the root

canal system through the use of instruments and effective irrigating solutions. The aim of

the present study was to evaluate the effect of different endodontic irrigating solutions on

the hardness of root canal dentine. Eighteen recently extracted, intact maxillary incisor

teeth were collected. The root canals were instrumented to an apical size #50 file, and

irrigated with saline solution. The prepared roots were divided into two groups each of

nine roots. Each root was sectioned transversely into cervical, middle and apical

segments. The sections of each root were separately mounted in a metal chuck with

acrylic resin. The coronal dentine surfaces of the root segments were polished. The

microhardness of the dentine was measured for the purposes of control data at 500 mm

and 1 mm from the pulpo–dentinal interface. The canal portions in the root segments

included in the first group were irrigated with 3% H2O2 and 5% NaOCl solutions used

alternatively, while 17% EDTA solution was the irrigation used in the second group. One

ml of each solution/segment was applied for 60s exposure time. After irrigation, dentine

microhardness was re-assessed. The results of the study showed irrigation with EDTA

gave more reduction of dentine hardness compared to H2O2/NaOCl irrigation. The study


30

concluded that both H2O2/NaOCl and EDTA irrigating solutions significantly reduced

the microhardness of root canal dentine18

.

The major objective in root canal treatment is to disinfect the entire root canal system,

which requires that all contents of the root canal system be eliminated. This study aims

to determine the antibacterial efficacy and the effect on micro‑hardness of root dentin by

one such herbal compound – Morinda citrifolia juice (MCJ) (6%) in comparison with

CHX (0.2%) and their combination. The 30 human permanent teeth, extracted for

therapeutic reasons were selected for this study. All the dentin blocks were infected with

Enterococcus fecalis for a period of 21 days. The experimental groups were Group I:

0.2% CHX; Group II: 6% MCJ; Group III: 6% MCJ + 0.2% CHX; Group IV: Saline.

After 28 days of medication with the irrigants, the dentin shavings from root canal dentin

was harvested and colony forming units counted. Part II for micro-hardness testing

consisted of preparing 32 root halves and mounted them on blocks of acrylic resin. 8

samples per group were randomly divided into the experimental groups. The samples

were then medicated with the irrigants for a period of 15 min and micro-hardness values

were recorded. The results showed part 1: Group I showed highest antibacterial activity

followed by Group III with Group II. Part 2: None of the groups showed any effect on

micro-hardness of root canal dentin. The study concluded that nearly 0.2% of CHX

showed the highest antimicrobial activity even after 28 days and 6% of MCJ also showed

antibacterial activity, but to a lesser degree than CHX. None of the irrigants tested had

any effect on the micro-hardness of root canal dentin43

.

During root canal preparation, irrigation is recommended in order to remove debris from

the root canal, kill microorganisms, and dissolve necrotic and vital tissue remnants. For


31

this reason, various irrigation solutions have been used in root canal treatment. The aim

of this study was to evaluate the effects of 1% sodium hypochlorite (NaOCl), 6%

Morinda citrifolia juice (MCJ), 2% chlorhexidine (CHX) solution or distilled water on

the microhardness of root canal dentin. 40 single-rooted mandibular premolar were used

for the study and were bisected longitudinally. Before and after irrigation, microhardness

values were obtained for the cervical, middle and apical levels of the root canal from a

0.5 µm utilizing a Vickers microhardness tester with a 50 g load and 15 sec dwell time.

The percent change in microhardness was calculated. Results showed MCJ and NaOCl

decreased the root canal dentin microhardness. CHX and distilled water, however, had no

effect on root canal dentin microhardness. Thus in vitro study showed that, the use of 6%

MCJ as an irrigation solution affected the dentin microhardness44

.

Irrigating solutions used during endodontic treatment may lead to alterations in the

chemical structure which may in turn affect the mechanical properties of dentin.

Therefore careful and judicious selection of irrigant is required which have maximum

benefits with minimum undesirable properties. The aim of the present study was to

evaluate the effect of various endodontic irrigants on the micro-hardness of the root canal

dentin. 80 freshly extracted mandibular premolars with single canals were decoronated at

the cemento-enamel junction. Roots were sectioned longitudinally into two halves.

Samples were then polished and placed in autopolymerised resin moulds with the

polished surface facing outside. The samples were divided into four groups based on the

irrigants in which they were immersed i.e., 3% Sodium Hypochlorite (3% NaOCl), 17%

Ethylene Dioxide Tetra Acetic Acid (17% EDTA), 0.2% Chitosan and 6% Morinda

citrifolia Juice (MCJ) for 15 minutes each. All the specimens were then subjected to


32

micro-hardness testing using a Vickers micro-hardness tester. Results of the present study

indicated that 17% EDTA and 0.2% Chitosan, significantly decreased the micro-hardness

of root dentin whereas 6% MCJ and 3% NaOCl had no significant effect on the

microhardness before and after immersing in the irrigants. Hence, it may be concluded

that herbal irrigants like MCJ may serve as an effective alternative to the conventionally

used root canal irrigants as they cause minimal alteration of dentin structure in addition to

being less toxic when compared with synthetic irrigants45

.

The aim of the study was to evaluate the effect of endodontic irrigants on microhardness

and roughness of root canal dentin. The author compared the effect of 0.2% CHX on the

microhardness and roughness of root canal dentin with widely used irrigants like 5.25%

NaOCl, 2.5% NaOCl, 3% H2O2, 17% EDTA. In this study all the specimens are treated

with these irrigant solutions for 15 minutes. The results indicated that all the irrigant

solutions except CHX significantly decreased microhardness of root canal dentin. 3%

H2O2 and 0.2 % CHX has no effect on roughness of the root canal dentin . Within the

limitations study concluded that although there are many other factors for irrigating

solution preferences, according to the results of the study 0.2% CHX was considered as

an appropriate endodontic irrigation solution because of its harmless effect on

microhardness of root canal dentin46

.

The purpose of this study was to evaluate the effect of single and combined use of

EDTA, ethylene gluygol bis tetra acetic acid (EGTA) EDTAC, tetracycline-HCL and

NaOCl on the microhardness of root canal dentin. All treatment regimens except distilled

water significantly decreased the microhardness of root canal dentin. The single and use

of EDTA decreased the microhardness of root canal dentin significantly more than other


33

treatment regimens. Compared with their single treatment versions, all combined

treatment regimens decreased the mean microhardness values significantly. A

comparison of single and combined treatment regimens revealed significant decreases

only for EDTA and EDTA and NaOCl in the coronal region and for EDTAC and

EDTAC and NaOCl in the apical and middle regions of the root canal. Results of the

study showed that the use of EDTA alone or prior to NaOCl treatment was both material

and region dependent. However for combined treatment regimens subsequent use of

NaOCl levels the statistical difference between the regional microhardness values

obtained after treatment with EGTA, EDTAC and tetracycline-HCL47

.

An in vitro study was done to evaluate the effects of endodontic irrigants on the

microhardness of root canal dentin. Thirty extracted single rooted teeth were used. The

crowns were sectioned at cement-enamel junction. Each root was transversely sectioned

into cervical, middle, and apical segments, making it in to 90 specimens. The three

sections of each root were separately mounted in an individual silicon device with acrylic

resin. The specimens were randomly divided in to following three groups (n=30),

according to the irrigant solution used : group 1 - control saline solution; group 2- 2%

Chlorhexidine; group 3-1% NaOCl . After 15 minutes of irrigation, dentin microhardness

was measured on each section with a diamond microhardness tester. The study results

showed that CHX and NaOCl solutions significantly reduced the microhardness of root

canal dentin48

.

The aim of the study was to evaluate NaOCl effects on primary and permanent pulp

chamber dentin. The dentin quality of primary and permanent pulp chamber was

inspected by Fourier-transformed Raman spectroscopy (FT-Raman) and scanning


34

electron microscopy (SEM). Fragments of pulp chamber dentin were obtained from 20

human molar crowns (primary and permanent). The fragments were assigned to 8 groups

(n = 5)—Primary teeth: G1, pulp chamber dentin; G2, pulp chamber dentin irrigated with

NaOCl 1% (30 min); G3, pulp chamber dentin irrigated with NaOCl 1% (30 min) and

etched by 35% phosphoric acid; G4, pulp chamber dentin etched by 35% phosphoric

acid. Permanent teeth: G5, pulp chamber dentin; G6, pulp chamber dentin irrigated with

NaOCl 1% (30 min); G7, pulp chamber dentin irrigated with NaOCl 1% (30 min) and

etched by 35% phosphoric acid; G8, pulp chamber dentin etched by 35% phosphoric

acid. The spectra were subjected to the Cluster analysis. The SEM images were scored. :

Inorganic content: the results of the study showed that there was a difference between

primary and permanent dentin. The groups treated with NaOCl were statistically similar

between them, but differed from the groups not treated. Organic content: There was no

difference between primary and permanent dentin. The groups became similar after

NaOCl and phosphoric acid treatments. The microscopic images showed the presence of

calcospherites on permanent dentin and their absence on primary dentin. Within the

limitations of this study it can be concluded that: the 1% NaOCl changes the organic and

inorganic content arrangement of primary and permanent dentin pulp chamber. The

changes caused by NaOCl in the inorganic content arrangement were not nullified after

phosphoric acid etching in both primary and permanent dentin. The SEM images did not

detect the inorganic content changes caused by NaOCl when followed by phosphoric acid

etching49

.

Dentin microstructure and its properties are very important in restorative dentistry. The

aim of this study was to measure the microhardness of root canal dentin using two types


35

of irrigating solutions( 0.2% Chlorhexidine and 5.25% Sodium Hypochlorite) with and

without use of different types of root canal files (Stainless Steel-K files, Nickel-Titanium

K-files or rotary Nickel-Titanium files). One hundred thirty human lower second

premolars with straight roots were used in this study. The teeth divided in to four

groups according to the type of irrigating solutions that used during root canal

instrumentation with the use of normal saline as a control group, then each group sub

divided in groups according to the instrument used in the root canal preparation, then

after irrigation and preparation the roots sliced and root dentin microhardness measured

using Vicker’s microhardness machine. The results of the study showed that the type of

instrument and Chlorhexidine have no effect on the microhardness of root canal dentin

while Sodium Hypochlorite significantly decrease the microhardness of root canal dentin

especially when use with Stainless Steel K-files and Nickel-Titanium K-files than when

used with rotary Nickel-Titanium files. The study concluded that the microhardness of

root canal dentin not affected by the type of root canal instruments. The use of 5.25%

Sodium Hypochlorite as a root canal irrigation significantly reduce the microhardness of

root dentin within 3 minutes. The use of Sodium Hypochlorite as a root canal irrigant

with stainless steel K-files or Nickel-Titanium K-files reduce the microhardness of

root canal dentin to greater extend than when use with rotary Nickel-Titanium files

because the working time required with Stainless Steel K-files or Nickel-Titanium K-

files was on the average three times longer than the working time with rotary

Nickel-Titanium files50

.

Apical periodontitis is an inflammatory reaction of periradicular tissues caused by

microbial infection in the root canal. Enterococcus faecalis is a species commonly


36

isolated from persistent root canal infections. The purpose of this study was to compare

the antibacterial effects of different disinfecting solutions on young and old E. faecalis

biofilms in dentin canals using a novel dentin infection model and confocal laser

scanning microscopy (CLSM). The bacteria were introduced into the dentinal tubules by

centrifugation. After 1 day and 3 weeks of incubation, 40 infected dentin specimens were

subjected to 1 and 3 minutes of exposure to disinfecting solutions, which included 2%

sodium hypochlorite (NaOCl) (EMD Chemicals Inc, Darmstadt, Germany), 6% NaOCl,

2% chlorhexidine (CHX) (Sigma Chemical Co, St Louis, MO), and Qmix (Dentsply

Tulsa Dental, Tulsa, OK). The proportions of dead and live bacteria inside the dentinal

tubules after exposure to these disinfectants were assessed by CLSM using a

LIVE/DEAD bacterial viability stain. The results of the study showed that 6% NaOCl

and Qmix were the most effective disinfecting solutions against the young biofilm,

whereas against the 3-weekold biofilm, 6% NaOCl was the most effective followed by Q-

mix. Two percent NaOCl was equally effective as 2% CHX. In conclusion, the present

study showed that mature E. faecalis biofilms in dentin canals are more resistant to

disinfecting solutions than young biofilms. Six percent NaOCl and QMiX had stronger

antibacterial effects against young and old E. faecalis biofilms in dentin than 2% NaOCl

and 2% CHX51

.

Irrigation, which serves a variety of purposes including antibacterial action, tissue

dissolution, cleaning and chelating, is an essential step during root canal treatment. This

study aimed to compare the effects of different irrigants on root dentine microhardness,

erosion and smear layer removal. A total of 72 root dentine slices were divided into six

groups, according to the final irrigants used: Group 1: 17% ethylenediamine tetra-acetic


37

acid (EDTA) + 2.5% NaOCl, Group 2: 7% maleic acid (MA) + 2.5% sodium

hypochloride (NaOCl), Group 3: 1.3% NaOCl + mixture of tetracycline, acid and

detergent (MTAD), Group 4: Smear Clear + 2.5% NaOCl, Group 5: 5% NaOCl, Group 6:

saline. Vickers microhardness values were measured before and after treatment. In total,

42 root-halves were prepared for scanning electron microscope to evaluate the amount of

smear and erosion in the coronal, middle and apical thirds. The results showed that

maleic acid showed the greatest reduction in dentine microhardness followed by EDTA

and MTAD. EDTA, maleic acid, MTAD and Smear Clear removed smear layer

efficiently in the coronal and middle thirds of root canal. However, in the apical region,

maleic acid showed more efficient removal of the smear layer than the other irrigants52

.

It has been well established that apical periodontitis is caused by microorganisms and

their products emanating from the root canal system. This aim of this study wss to

evaluate the effect of the smear layer on the antibacterial effect of different disinfecting

solutions in infected dentinal tubules. Cells of Enterococcus faecalis were forced into

dentinal tubules according to a previously established protocol. After a 3-week incubation

period of infected dentin blocks, a uniform smear layer was produced. Forty infected

dentin specimens were prepared and subjected to 3 and 10 minutes of exposure to

disinfecting solutions including sterile water, 2% and 6% sodium hypochlorite (NaOCl),

2% chlorhexidine (CHX), 17% EDTA, and QMiX. The following combinations were

also included: 2% NaOCl + 2% CHX, 2% NaOCl + QMiX, 6% NaOCl + QMiX, and 6%

NaOCl + 17% EDTA + 2% CHX. Four other dentin specimens similarly infected but

with no smear layer were subjected to 3 minutes of exposure to 2% CHX and 6% NaOCl

for comparison. Confocal laser scanning microscopy and viability staining were used to


38

analyze the proportions of dead and live bacteria inside the dentin. The results showed

that, in the presence of a smear layer, 10 minutes of exposure to QMiX, 2% NaOCl +

QMiX, 6% NaOCl + QMiX, and 6% NaOCl + 17% EDTA + 2% CHX resulted in

significantly more dead bacteria than 3 minutes of exposure to these same disinfecting

solutions. ; 6% NaOCl + QMiX and 6% NaOCl + 17% EDTA + 2% CHX showed the

strongest antibacterial effect. In the absence of a smear layer, 2% CHX and 6% NaOCl

killed significantly more bacteria than they did in the presence of a smear layer. Within

the limitations of the present study, the use of QMiX or 6% NaOCl followed either by

QMiX or possibly by EDTA and CHX together results in good disinfection of dentin53

.

The use of antiseptic irrigating solutions is an important part of chemo-mechanical root

canal preparation. The aim of the study is to investigate the mechanical, chemical and

structural alterations of human root dentine following exposure to ascending sodium

hypochlorite concentrations. Three-point bending tests were carried out on standardized

root dentine bars (n ¼ 8 per group, sectioned from sound extracted human third molar

teeth) to evaluate their flexural strength and modulus of elasticity after immersion in 5 ml

of water (control), 1% NaOCl, 5% NaOCl or 9% NaOCl at 37 C for 1h. Additional

dentine specimens were studied using microelemental analysis, light microscopy

following bulk staining with basic fuchsin, and scanning electron microscopy (SEM).

The results showed immersion in 1% NaOCl did not cause a significant drop in elastic

modulus or flexural strength values in comparison to water, whilst immersion in 5% and

9% hypochlorite reduced these values by half (P < 0.05). Both, carbon and nitrogen

contents of the specimens were significantly (P < 0.05) reduced by 5% and 9% NaOCl,

whilst 1% NaOCl had no such effect. Exposure to 5% NaOCl rendered the superficial


39

80–100 lm of the intertubular dentine permeable to basic fuchsin. Three-dimensional

SEM reconstructions of partly demineralized specimens showed NaOCl concentration-

dependent matrix deterioration. Backscattered electron micrographs revealed that

hypochlorite at any of the tested concentrations left the inorganic dentine components

intact. The study concluded that The current data link the concentration-dependent

hypochlorite effect on the mechanical dentine properties with the dissolution of organic

dentine components54

.

Methodology

40

METHODOLOGY

MATERIALS AND METHODS

Source:

Eighty human single rooted mandibular premolar teeth extracted for periodontal and

orthodontic reasons were collected from the Department of Oral and Maxillofacial

Surgery, D.A.P.M RV Dental College, Bangalore.

METHOD OF COLLECTION AND STORAGE OF SAMPLES:

The present study was done in Department of Conservative Dentistry and Endodontics,

D.A.P.M. RV Dental College. Extracted human mandibular premolars were collected

from Department of Oral and Maxillofacial Surgery. The teeth were stored, disinfected

and handled as per recommendation and guidelines laid down by Occupational Safety

and Health Administration (OSHA) and Centre for Disease Control (CDC).

The protocol was carried out as follows:

Calculus was mechanically removed by ultrasonic scaling tips

Teeth were stored in 10% formalin for 2 weeks as per standard sterilization protocol.

After sterilization, samples were stored in distilled water until further use.

Methodology

41

INCLUSION CRITERIA

Teeth with single root and straight canal

Teeth without root fracture

Teeth with completely formed roots

Teeth without caries or restoration

EXCLUSION CRITERIA

Teeth with root caries, cracks or fractures

Multi rooted teeth

Teeth with open apices

Teeth with curved roots

Teeth with calcified canals

Teeth with developmental defects

ARMAMENTARIUM

1. 80 single rooted mandibular premolar

2. Airotor hand piece (NSK Pana Air)

3. Slow speed micromotor hand piece (NSK)

4. # 2 Access opening bur (Dentsply)

5. K files (Dentsply)

6. 3% Sodium hypochlorite (Vensons, Bangalore, India)

Methodology

42

7. 2% Chlorhexidine Gluconate (RC-CHLOR,Azure Laborataries, kerala)

8. 6% Morinda Citrifolia Juice (Apex Biotech Lab, Chennai)

9. Normal saline

10. Distilled water(10ml, Axa Parenterals Ltd)

11. 50ml Glass beaker

12. Absorbent paper points

13. Acrylic block (2*2 inches size)

14. Silicon carbide paper(800, 1000, 1500 and 2500 grit -3M)

15. Emery paper

16. Felt cloth

17. 30 gauge needle tip (Navi tip , Ultradent)

18. Double sided diamond disc(HORICO diamond disks, coarse grit- 1350μ)

19. Chisel

20. Stereomicroscope (Labomed CZM 4,Novel Technologies)

21. Vickers hardness tester(Microhardness tester FM-800)

Preparation of Morinda Citrifolia juice

6% MCJ was freshly prepared by taking 6ml of MCJ and diluting it to100 ml normal

saline using pipette.

Methodology

43

Vickers Hardness Tester (Future Tech)

Vickers hardness study was done in the Department of Material Science Engineering in

Indian Institute of Science (IISc), Bangalore.

Stereomicroscope

Stereomicroscopic study was done in the Department of Oral pathology in D.A.P.M.R.V.

Dental college, Bangalore

METHODOLOGY

Eighty straight single-rooted lower premolars with relatively similar dimension and

morphology, freshly extracted with closed apices was collected (Fig 1). Each tooth was

radiographed to confirm the presence of a single canal. Teeth with previous root caries,

cracks, curved canals, endodontic treatment, internal resorption or calcification was

excluded. The selected teeth was cleaned from debris, calculus and soft tissue remnants

on the root surface and stored in sterile saline solution at room temperature during the

study. Teeth were decoronated at the cementoenamel junction using low speed diamond

disc and crowns were discarded (Fig 2&3).

PART I: SMEAR LAYER EVALUATION

A total of 40 roots was used in this part. The root canals were randomly divided into

equal 4 groups according to the final irrigation solutions(Fig 5). Access opening done

(Fig 6) and canals were enlarged up to master apical file number (50k file) using step

back technique. During instrumentation, the canals of 4 groups was recapitulated and

Methodology

44

irrigated with 5 ml of normal saline (Fig 7). After completed instrumentation final

irrigation was done with one of the tested solutions (Fig 8). A 30-G needle, which

penetrates to within 1-2 mm from the apex, was used for irrigation. No instrumentation

was performed during the final irrigation with the test solutions. The irrigant solutions

used in each group are as follows.

Group 1: 5 ml of 3% NaOCl for 3 mins (Fig 4,5&8)

Group 2: 5ml of 6% Morinds Citrifolia juice for 3 mins (Fig 4,5&8)

Group 3: 5ml of 2% Chlorhexidine Gluconate for 3 mins (Fig 4,5&8)

Group 4: 5ml of normal saline for 3 mins (Fig 4,5&8)

After final irrigation, each root canal was dried with absorbent paper point and the canals

orifice was sealed with a small cotton pellet to prevent contamination of the root canal

space during sectioning procedures. Two longitudinal grooves was prepared on the

palatal/lingual and buccal surfaces of each root using a diamond disc (Fig 9), avoiding

penetration into root canals. Each root was then split longitudinally into two halves using

a mallet and a Stainless-Steel chisel (Fig 10).

STEREOMICROSCOPIC EVALUATION

The specimen was randomly chosen and placed under reflecting light of

stereomicroscope under 20x magnification and observed for smear layer (Fig 11). The

amount of smear layer remained on the surface of root canal or in the dentinal tubules

was scored according to the following criteria.

Methodology

45

Samples were graded according to the rating scale from 1-3.

Scale 1- indicating a clean canal with no or very little debris present;

Scale 2 -for debris present in less than half the evaluated canal region

Scale 3 -for debris occupying more than half the evaluated canal region.

PART II: MICROHARDNESS EVALUATION

A total of 40 roots were used in this part. Access opening done (Fig 6) and working

length was recorded by placing #10 K-file just seen through the apical foramen. The

working length was determined by reducing 1mm from this recorded length. The

cleaning and shaping of root canals was done till # 25 size K- file up to the working

length (Fig 7). Recapitulation was done during instrumentation. During instrumentation,

distilled water was used for root canal irrigation after each file use.

The roots were sectioned longitudinally into 2 parts using low speed micromotor with

diamond disc under water coolant (Fig 12). For longitudinal sectioning of the root,

longitudinal grooves was made on buccal and lingual external root surface. These

grooves were made using double-faced diamond disc at low speed with care not to

penetrate the root canals. Root specimens were then splitted with a chisel into two

segments giving 80 halves (Fig 13).

The root segments were horizontally embedded in auto-polymerizing resin leaving the

dentin exposed to facilitate manipulation and improve metallographic preparation (Fig

14,15). The dentin surface of mounted specimen were then grounded flat and smooth on

a circular grounding machine with a series of silicon carbide abrasive papers (500, 800,

1000, 1200, 1500, and 2000 grit) under distilled water to remove any surface scratches

and finally polished with fine grades of composite polishing kit (Fig 16). Each root half

Methodology

46

was labeled on the acrylic block for indentation by a known private number after

embedding in acrylic blocks during acrylic setting .

CLASSIFICATION OF EXPERIMENTAL GROUPS

Total forty root halves without cracks or surface defects were selected, randomly divided

into 4 groups with 10 samples in each group (n=10) according to the irrigating solution

used for 5 minutes (Fig 5)

Group 1: 20 specimens will be immersed in 3% NaOCl.

Group 2: 20 specimens will be immersed in 6% Morinda citrifolia juice

Group 3: 20 specimens will be immersed in 2% Chlorhexidine Gluconate

.Group 4: 20 specimens will be immersed in Normal saline ( control group ).

In order to prevent the dilution of the irrigants before the experiment, excess fluid was

removed from the canal surface using sterile paper points. The root specimen of each

section was immersed in the tested irrigant solutions for 5 min in closed glass plates. All

experimental specimens was flushed with 30 ml sterile saline. Specimens were then dried

with sterile paper points. The microhardness was measured for canal dentine surface after

immersion.

Surface treatment:

Immediately after baseline measurements of microhardness, each specimen of the group

was immersed in 50ml of irrigating solution according to the test group (Fig 17). At the

Methodology

47

end of active treatment period, the specimens were rinsed with distilled water and blotted

dry. Post –treatment microhardness values were obtained.

Microhardness Testing:

The Vickers hardness test was developed in 1921 by Robert L. Smith and George E.

Sandland at Vickers Ltd as an alternative to the Brinell method to measure the hardness

of materials. It is suitable for determining the hardness of brittle material and it has also

been used for determining the hardness of tooth material (Fig 20). The basic principle is

to observe the questioned material's ability to resist plastic deformation from a standard

source. A diamond in the form of a square-based pyramid is used as an indenter capable

of producing geometrically similar impressions, irrespective of size. The Vickers test has

one of the widest scales among hardness tests.

SCHEMATIC DIAGRAM OF VICKER’S INDENTER HAVING SQUARE SHAPED

INDENTER WITH TWO DIAGONALS (d1 and d2).

Methodology

48

In this study dentin microhardness was determined using Future Tech microhardness

indenter installed in the Department of Materials Science Engineering, Indian Institute of

Science, Bangalore. The specimens were mounted on stage of Vicker’s microhardness

tester. 200-g load and a 20 seconds dwell time were used. Three separate indentations

were made parallel to the edge of the root lumen at the mid-root level. Indentations were

made at the depth of 100μm from the pulp–dentin interface (Fig 18&19). The lengths of

the 2 diagonals were used to calculate the Vicker’s micro hardness number (VHN). The

representative hardness values were calculated by taking the average of the 3

indentations. Microhardness values were obtained before and after treatment with test

solutions. of producing geometrically similar impressions, irrespective of size. The

Vickers test has one of the widest scales among hardness tests.

Vickers hardness = KP/L218

In the equation, the value of K is 1.854

Sample size estimation

49

SAMPLE SIZE ESTIMATION

Analysis: A priori: Compute required sample size

Input: Effect size f = 0.40

α err prob = 0.05

Power (1-β err prob) = 0.80

Number of groups = 4

Output: Noncentrality parameter λ = 12.1600000

Critical F = 2.7318070

Numerator df = 3

Denominator df = 72

Total sample size = 76

Actual power = 0.8234006

The sample size has been estimated using the software GPower v. 3.1.9.2

Considering the effect size to be measured (f) at 40%, power of the study at 80% and the

margin of the error at 5%, the total sample size needed is 76. Rounding off the sample size

to 80, each group will consists of 20 samples. [20 x 4 groups = 80 samples]

STATISTICAL ANALYSIS:

Statistical Package for Social Sciences [SPSS] for Windows Version 22.0 Released 2013.

Armonk, NY: IBM Corp., will be used to perform statistical analyses.

Descriptive Statistics: It includes expression of the smear layer removal scores and

micro-hardness of dentin in terms of Mean & SD.

Sample size estimation

50

Inferential Statistics:

One-way ANOVA test followed by Tukey's HSD post hoc Analysis will be used to

compare the mean smear layer removal scores and micro-hardness of dentin between

different study groups.

The level of significance [P-Value] was set at P<0.05

And any other relevant test, if found appropriate during the time of data analysis will be

dealt accordingly.

Results

51

RESULTS

One-way ANOVA Test followed by Tukey's Post hoc Analysis was used to compare the

mean Dentin Micro Hardness between 4 groups during Before and After immersion in

irrigants. Student Paired t Test was used to compare the mean Dentin Micro Hardness

Before and After Immersion into irrigants in each study group. Kruskal Wallis Test

followed by Mann Whitney Post hoc analysis was used to compare the mean smear layer

removal scores between different irrigants.

The level of significance [P-Value] was set at P<0.05

Descriptive analysis includes expression of Dentin Micro Hardness and Smear Layer

removal Scores in terms of Mean & SD. Statistically significant results were detected

between all the groups for both smear layer removal and microhardness.

Table no.2:Comparison of mean Smear Layer Removal Scores between

Irrigants using Kruskal Wallis Test

Groups N Mean SD Min Max P-Value

Group 1 20 1.35 0.49 1 2

<0.001* Group 2 20 1.90 0.79 1 3

Group 3 20 2.50 0.69 1 3

Group 4 20 2.60 0.60 1 3

*Statistically significant

Results

52

In this study, the mean smear layer removal score of root canal space which is irrigated

with 3% NaOCl was 1.35+/-0.49. The smear layer removal score of root specimens

irrigated with 6% MCJ is 1.90 +/- 0.79. The smear layer removal score of root specimens

irrigated with 2% CHX is 2.5+/-0.69. The smear layer removal score of root specimens

irrigated with normal saline is 2.60+/-0.60.

The minimum reduction in smear layer removal was noticed in Group IV in which the

specimen is treated with normal saline. The smear layer removal score was noticed less in

Group I which the specimen was treated with 3% NaOCl for 3 minutes indicating clean

canals. The reduction in smear layer removal score in Group II is less when compared to

Group III and Group IV and more than Group I. The order of smear layer removing

ability order among groups is as follows:

Group I > Group II > Group III > Group IV.

Table no.3: Multiple comparison of mean Smear Layer Removal scores b/w different

Irrigants using Tukey's Post hoc Analysis

(I) Groups (J) Groups

Mean Diff. (I-

J)

95% CI for the Diff.

P-Value Lower Upper

Group 1 Group 2 -0.55 -1.09 -0.01 0.02*

Group 3 -1.15 -1.69 -0.61 <0.001*

Group 4 -1.25 -1.79 -0.71 <0.001*

Group 2 Group 3 -0.60 -1.14 -0.06 0.02*

Group 4 -0.70 -1.24 -0.16 0.005*

Group 3 Group 4 -0.10 -0.64 0.44 0.68


Results

53

Table no 4: Comparison of mean Dentin Micro Hardness Values between different

groups before immersing in Irrigants using One-way ANOVA Test


Group 1 20 64.218 4.021 57.90 70.98

0.84 Group 2 20 63.857 2.336 59.14 67.94

Group 3 20 64.779 3.176 58.14 69.74

Group 4 20 64.274 3.051 58.48 69.24

Group1- 3% NaOCl, Group 2- 6% MCJ, Group 3- 2% CHX, Group 4- Normal Saline

Table no.5: Comparison of mean Dentin Micro Hardness Values between different

groups After immersing in Irrigants using One-way ANOVA Test


Group 1 20 52.172 2.665 47.43 59.53

<0.001* Group 2 20 57.322 2.063 53.76 61.30

Group 3 20 59.979 3.950 53.31 66.35

Group 4 20 63.034 3.298 56.16 68.12

*Statistically Significant

In the present study mean microhardnes (VHN) of root canal dentin treated with 3%

NaOCl was 64.218 +/- 4.021. Mean microhardness (VHN) of root canal dentin treated

with 6% MCJ was 63.857 +/- 2.336. Mean microhardness (VHN) of root canal dentin

Results

54

treated with 2% CHX was 64.779 +/-3.176. Mean microhardness (VHN) of root canal

dentin treated with normal saline was 64.274 +/- 3.051.

The highest value of microhardness was obtained in control group. When compared with

the control group , maximum reduction in microhardness was noted in Group I in which

the specimens were treated with 3%NaOCl . The minimum reduction in microhardness

were noted in Group IV in which all the specimens were treated with normal saline. The

reduction in microhardness of Group II is little more when compared to Group III and

Group IV. The reduction in hardness among the tested group was as follows.


Table no.6: Multiple comparison of mean dentin Micro Hardness b/w groups after

immersing in Irrigants using Tukey's Post hoc Analysis


Mean Diff.

(I-J)


P-Value Lower Upper

Group 1 Group 2 -5.150 -7.705 -2.595 <0.001*

Group 3 -7.808 -10.362 -5.253 <0.001*

Group 4 -10.862 -13.417 -8.307 <0.001*

Group 2 Group 3 -2.658 -5.212 -0.103 0.04*

Group 4 -5.712 -8.267 -3.157 <0.001*

Group 3 Group 4 -3.055 -5.609 -0.500 0.01*

*Statistically Significa

Results

55

Table no.7: Comparison of mean Dentin Micro Hardness during Before and After

immersion in Irrigants in each group using Student Paired t test

Groups Immersion N Mean SD Mean Diff P-Value

Group 1

Before 20 64.218 4.021 12.047 <0.001*

After 20 52.172 2.665

Group 2

Before 20 63.857 2.336 6.536 <0.001*

After 20 57.322 2.063

Group 3

Before 20 64.779 3.176 4.800 <0.001*

After 20 59.979 3.950

Group 4

Before 20 64.274 3.051 1.241 <0.001*

After 20 63.034 3.298

Results

56

GRAPH 1 : MEAN SMEAR LAYER REMOVAL SCORE BETWEEN IRRIGANTS

GRAPH 2 : COMPARISON OF MEAN DENTIN MICROHARDNESS VALUES

BETWEEN DIFFERENT GROUPS BEFORE IMMERSING IN IRRIGANTS

Results

57


BETWEEN DIFFERENT GROUPS AFTER IMMERSING IN IRRIGANTS


BETWEEN DIFFERENT GROUPS BEFORE AND AFTER IMMERSING IN

IRRIGANTS

Results

58

THE STEREOMICROSCOPIC IMAGE OF ROOT CANAL SPACE FOR

SMEAR LAYER AT 20X MAGNIFICATION AFTER IRRIGATING

WITH TEST IRRIGANTS.

fig 20: odium hypochlorite (NaOCl)

fig 21: Morinda Citrifolia Juice (MCJ)

Results

59

Fig 22: Chlorhexidine Gluconate (CHX)

fig 23: Saline

Discussion

60

DISCUSSION

The primary objective of a root canal treatment is to render the root canal free from all

microbes and to disinfect it39

. Due to the complex anatomy of the root canals it requires

both chemical and mechanical cleaning and shaping of the canal space. Irrigants can

augment mechanical debridement by flushing out debris, dissolving tissue, and

disinfecting the root canal system11

.

During the preparation of root canals using hand or rotary instrument, small amounts of

debris get accumulated on the walls of the canals containing microorganisms, otherwise

known as smear layer38

. The smear layer is made up of mainly small particles of

mineralized collagen matrix, bacteria and bacterial products that might act as niche for

irritants. According to various studies, the presence of smear layer blocks the penetration

of intracanal medication into the irregularities of the root canal system and the dentinal

tubules and also prevents adaptation of obturating materials to the cleaned and shaped

root canal surface23

. Therefore, its removal is important to enhance canal disinfection and

adhesion of resin sealer to root canal dentin.

Dentin is a mineralized tissue composed of inorganic components of hard tissues, in

which calcium and phosphorous are distributed in the form of hydroxyapatite crystals55

.

Apart from the beneficial effects, irrigants may exhibit detrimental effects on dentin or on

root canal filling materials14

. While removing the smear layer, irrigation materials create

a relative softening of the dentinal walls, which in turn facilitate the preparation of root

canal . On the other hand, decrease in the microhardness can affect the adhesion and

sealing ability of the sealers to the root dentine walls52

.

Discussion

61

Therefore, the present study aimed to assess and compare comparative evaluation of

different endodontic irrigants on smear layer and microhardness of dentin.

In the present study, 3% NaOCl, 6% MCJ , 2% CHX and normal saline was used as

conventional irrigants as maximum disinfection can be achieved by these irrigants. The

new irrigant used in this study is Morinda Citrifolia Juice (MCJ). Sodium hypochlorite is

used in endodontics for two main purposes: (i) to dissolve pulp tissue, and (ii) to destroy

bacteria. In endodontics, concentrations of 0.5% to 5.25% are regularly used. Even a

0.5% concentration is considered by some to be too toxic for wound care. The higher the

concentration of sodium hypochlorite, the greater would be the deleterious effects on

dentine like reduction of the elastic modulus and the flexural strength56

. MCJ which is

herbal extract can be used as a substitute for NaOCl with a safer irrigation solution with

the same effect on smear layer and the least deteriorating effect on microhardness29

.

The use of 2% CHX has been recommended as a irrigant for disinfection because of its

antimicrobial property and substantivity. But it does not have any effect on smear layer

removal.

In the present study, 0.9% Normal saline (control group) revealed the least smear layer

removal ability when compared to that of Group I (3% NaOCl), Group II (6% MCJ) ,

Group III (2% CHX). Stereomicroscopic evaluation of (Group I) 0.9% normal saline

showed the presence of smear layer and collection of surface debris in all the samples

studied. This is attributed to the inability of control group to remove the smear layer

which is in agreement with Garberoglioetal57

and McComb and Smith9. The normal

saline solution doesn’t have any effect on the removal of the smear layer as it is isotonic

Discussion

62

in nature and has no antibacterial or tissue dissolving ability. When used during

instrumentation, 0.9% saline solution produces a sludge layer made up of residual debris

that occludes the dentinal tubules. There was statistically significant difference between

saline (Group IV) and NaOCl ( Group I), MCJ(Group II) and CHX(Group III).

In this present study although 3% NaOCl (group I) reduced the debris load in all the

specimens at 3 levels of the canal coronal, middle and apical, of the specimen in

comparison to 6%MCJ (group II), and CHX (group III). Irrigation with 3 ml of 3%

NaOC1 after instrumentation in this study did an excellent job of removing superficial

debris whether delivered with an endodontic irrigation needle or the ultrasonic device.

The use of NaOC1 for root canal irrigation may dissolve the organic components and

leave a smear layer of mineralized tissue22

. In many investigations scrubbing the dentinal

walls with cotton soaked in NaOCl reduced the thickness of the smear layer57

. In the

current study smear layer removal was seen more at coronal third of the sample.

Therefore, NaOCl is highly efficient in removing the organic component of smear layer.

Study by Goldman et al and Yamada et al. found that the use of a high volume final flush

with 17% EDTA followed by NaOCl effectively removed the smear layer. They

speculated that the combination of EDTA and NaOCl effectively removes the inorganic

and organic components of the smear layer respectively57

. Another factor is the time

spent on chemical and mechanical cleaning of the tooth. It is a known fact that the

effectiveness of NaOCl does increase with an increase with contact time with the

solution. In addition, a longer time spent on instrumentation may remove more smear

layer38

.

Discussion

63

It may be noted that the removal of smear layer by intracanal irrigants is generally more

seen in the coronal and middle aspects of root canal in comparison to apical thirds. The

larger canal diameter in the coronal and middle thirds exposes the dentin to a higher

volume of irrigant, thereby allowing a better flow of the solution and thus a more

adequate removal of the smear layer58

.

Most of the chemical irrigants that we use today has many deleterious effect on tooth.

Therefore, a shift in focus has taken place toward the search for more biocompatible

substitutes over the traditionally used irrigants. The use of herbal irrigants may thus be of

interest to endodontic professionals as a part of the increasing trend to seek natural

remedies for root canal treatment. MCJ has been advantageously used as an endodontic

irrigant as it is a biocompatible antioxidant irrigant and has no adverse effects.

In the present study, 6% MCJ was not found to have satisfactory smear layer removal

properties. The minimal removal of smear layer observed with 6% MCJ may be

attributed to acids such as caproic acid, ursolic acid, and caprylic acid, which may be

responsible for its smear layer removal action58

. The use of 6% MCJ was less effective at

removing smear layer than compared to NaOCl59

.

Chlorhexidine has been used in various concentrations (0.002-2%) with different periods

of contact time between the disinfectant and various microorganisms. Chlorhexidine is a

potent antiseptic, which is widely used for chemical plaque control in the oral cavity.

Aqueous solutions of 0.1-0.2% are recommended for this purpose, whereas 2% is the

concentration for root canal irrigating solution usually found in endodontic literature.

Chlorhexidine is active against a wide range of yeast, fungi, facultative anaerobes,

Discussion

64

aerobes, gram negative organisms and gram positive such as Enterococcus faecalis.

Chlorhexidine could maintain the canal free of microorganisms, even after biomechanical

preparation because of its adsorption capacity and slow liberation of active cations by the

dental tissues60

. However, in the present study the results are contrast as chlorhexidine

showed least smear layer removal.

Torabinajed etal (2003) reported that the opening of the dentin tubules was greater in

coronal third than the apical third in relation to insuffient irrigation due to the small

diameter of the apical part. Similarly, in this study, all solutions that removed the smear

layer due to its better contact with the tooth surface at coronal and middle third which led

to dentin tubules that were opened more in the coronal and middle part than the apical

part61

.

Dentin microhardness value of pulpless teeth is less when compared to that of vital teeth.

Also, biomechanical property of dentin alters after the loss of vital tissue. Microhardness

of tooth structure is sensitive to composition, surface change of tooth. There is a very

important relation between microhardness of root dentin and the irrigating solution used.

The primary factors that govern the action of an irrigant are contact time and

concentration. Optimum contact time that an irrigant solution must be kept in root canals

to remove the smear layer is yet unclear39

. According to a study by Calt S etal. has also

been proven that EDTA and NaOCl have deleterious effects on root dentine if applied for

a longer duration. Baumgartner and Mader suggested that NaOCl caused a progressive

dissolution of dentin at the expense of peritubular and intertubular areas, and they

Discussion

65

suggested that this effect may have resulted from the action of NaOCl, which dissolved

the organic component of the dentin62

.

Peritubular dentin is highly mineralized and therefore harder than intertubular dentin.

The hardness of peritubular dentin may provide added structural support for the

intertubular dentin. Lower collagen content makes peritubular dentin more quickly

dissolvable in acid than is intertubular dentin62

.

Another determinant that has a profound effect on the post-treatment microhardness

values of dentin is the concentration of the irrigation solution. As the concentration of

NaOCl increases, its bactericidal and smear layer removal efficacy also increases39

. Thus,

in this study, 3% NaOCl was chosen as the irrigant in Group I. Therefore, although in

vitro studies demonstrate successful results with low concentrations of NaOCl, clinically,

higher concentrations and longer durations maybe required to reach the same results due

to the presence of the organic materials in the root canal, which can deactivate the

chlorine ion within one minute. Although the effectiveness of lower concentrations can

be improved by using larger volumes of irrigant, replenishing the irrigant frequently and

increasing the contact periods63

. At the same time the antimicrobial effect of sodium

hypochlorite is very less. A study by Dogan and Qalt et al verified that the use of 2.5%

NaOCl as irrigant for 15 minutes significantly altered the mineral content of root dentin.

It was reported that NaOCl treatment caused mineral accumulation in human root dentin,

increased the amount of carbonate, and reduced the amount of phosphate64

.

Morinda Citrifolia Juice (MCJ) appears to be the first juice to be identified as a possible

alternative to the use of NaOCl8. Apart from the bioactive compounds which are

Discussion

66

responsible for the antibacterial property of Morinda citrifolia juice, it also contains

organic acids like caproic acid, ursolic acid and caprylic acid. 6% MCJ has little effect

on microhardness of root canal dentin but very less as compared to NaOCl. The reduction

in microhardness could be due to the presence of these organic acids64

.

Various studies has demonstrated that 0.2% chlorhexidine solution had no effect on

microhardness of root canal dentin. However, this concentration is not frequently used as

an endodontic irrigant. Many studies have shown that 2% chlorhexidine has antimicrobial

efficacy similar to 5.25% NaOCl, this way, this concentration is the most commonly used

endodontic irrigant. In the present study, the use of 2% chlorhexidine solution slightly

decreased the microhardness of root canal dentin48

.

Various methods have been used to evaluate the surface change of dental hard tissues due

to alteration in calcium, phosphorous ratio of dental tissue. These include micro hardness

measurement, micro radiographic assessment, scanning electron microscopic methods,

energy dispersive spectrometric analysis, micro multiple internal reflectance, fourier

transform infrared spectroscopy(micro-MIR FTIR) and surface roughness testing65

.The

micro hardness measurement is one of the simplest non destructive mechanical

characterization method. It is known that the dentine micro hardness is proportional to the

amount of calcified matrix per mm2 and its determination provides indirect evidence of

mineral loss or gain in the dental hard tissue66

. Although a reduction in microhardness

facilitates the instrumentation throughout the root dentin, it may also weaken the root

structure. Microhardness of dentin may vary considerably within teeth67

. In the present

study, the average of three indentations at 100μm before irrigation was obtained to

provide a representative value of the initial microhardness of each specimen and the

Discussion

67

microhardness measurement was performed for each sample at baseline and after

treatment with irrigating solutions for 3 mins. The suitability and practicality of Vickers

micro hardness test for evaluating surface changes of dental hard tissue treated with

chemical agents have been proved effective in various studies. This method of micro

hardness test is adopted in this study.

Results of the study show significant reduction of micro hardness in all specimens after

treating with different irrigating solutions. The control group (Group IV) showed least

reduction and highest reduction was seen Group I followed by Group II(6% MCJ).

Eventhough there was no significant difference between group III and Group IV the

micro hardness reduction of Group III was little more compared to Group IV. Normal

saline was used as a control as it is shown that saline doesn’t alter the micro hardness of

root canal dentine compared to other experimental groups.

The reduction in dentine micro hardness of teeth treated with irrigating solutions have

several reasons. First, such flushed solutions could attribute lose of collagen, which is the

main organic component of dentine. Second, treatment with irrigating solution resulted in

removal of Magnesium and Carbonate ion from dentine crystals. Third, the irrigating

solution can soften the dentine by chelating and binding calcium ions from dentine.

Studies showed that NaOCl reduced modulus of elasticity and flexural strength of

dentine. NaOCl with PH of 7.4-11.5 cost 70% protein depletion from the Hydroxyapatite

surfaces68

. Dentine contains 22% organic material mainly Type I collagen which

contributes to it mechanical properties. Depletion of the organic phase after treatment

with NaOCl causes reduction in micro hardness of root canal dentin69

.

Discussion

68

The result of this study showed that 2% chlorhexidine gluconate significantly reduced the

microhardness of root canal dentin, this is in accordance with the study conducted by

Oliveira et al, in which they found a statistically significant decrease in the microhardness

of root dentin when 2% chlorhexidine gluconate was used on specimens for 15 minutes.

The reason for decrease in microhardness was not explained by the author nor has been

confirmed in any other study70

. The present study also revealed that saline did not

decrease or increase the dentin microhardness at all time intervals of treatment. This was

in accordance to a study done by Deepa et al, where it was concluded that saline had no

effect on microhardness of dentin at different time intervals71

.

There is no consensus on optimal amount of reduction in root dentin microhardness that

facilitates both mechanical instrumentation as well as that avoids mineral loss and

weakening of dental hard tissues following the use of root canal irrigants. The

determination of microhardness provide an indirect evidence of mineral loss or gain in

dental tissue. In this study it was possible to use large amount of irrigating solution in

close contact with flat dentin surface. In clinical situation this is not applicable as root

canal system has complex morphology and thus may not accurately correlate the extend

to which these chemical alterations may effect the adhesion of sealers to treated surface.

Results of this study shows that none of the irrigants completely remove the smear layer

from root canal walls, NaOCl helps in dissolving the organic component of smear layer

there by reducing the debris load followed by Morinda Citrifolia Juice which also mildly

remove the smear layer because of its organic acid content. Also Morinda Citrifolia Juice

can be a viable and biocompatible alternative to NaOCl as it cause little reduction in

dentin microhardness following irrigation.

Conclusion

69

CONCLUSION

LIMITATIONS :

In the current study, the irrigation delivery systems and irrigation activation techniques

which also influence the effectiveness of irrigating solutions for smear layer removal

and microhardness was not taken into consideration.

On evaluating the results of the study, the following facts emerge :

1. 3% NaOCl and 6 % MCJ showed reduction in smear layer and least was shown by 2%

CHX and normal saline.

2. A significant deteriorationof dentin substrate was evident with the use of 3% NaOCl

followed by 6% MCJ.

3. Among the conventional root canal irrigants ,CHX showed less reduction of dentin

microhardness,

4. Control group, 0.9 % saline did not show any changes in microhardness of root dentin

and did not have the ability to remove smear layer.

Thus within the limitation of this in vitro study, it can be concluded that 6% MCJ can be

considered as a potential alternative to conventional irrigants as far as the smear layer

removal and dentin microhardness is concerned. The present study establishes that the

use of the novel irrigant MCJ has removed the debris load and didn’t hamper the root

dentin microstructure when compared with the conventional irrigants. However, long

term studies are required with this new material for routine use as an endodontic irrigant

in clinical practice.

Summary

70

SUMMARY

The purpose of this study was to compare the changes in microhardness of dentin and

smear layer removal caused by different novel irrigant solutions like sodium

hypochlorite, morinda citrifolia juice, chlorhexidine and saline.

Eighty straight single-rooted lower premolars with closed apices was collected for the

study and decoronated at the cementoenamel junction using low speed diamond disc.

For smear layer evaluation ,on 40 specimens access opening was done and root canals

were enlarged up to master apical file number (50k file) using step back technique.

During instrumentation, the canals of 4 groups was recapitulated and irrigated with 5 ml

of normal saline followed by final irrigation with test solutions for 3 minutes. The test

irrigants used are 3% NaOCl, 6% MCJ, 3%CHX,and normal saline. After final irrigation,

tooth were sectioned longitudinally using a diamond disc. The specimen were placed

under reflecting light of stereomicroscope under 20x magnification and observed for

smear layer. For microhardness evaluation, remaining 40 samples were used, access

opening and cleaning and shaping was done. The roots were sectioned longitudinally into

2 parts using slow speed micromotor. The root segments were horizontally embedded in

auto-polymerizing resin leaving the dentin exposed to facilitate manipulation and

improve metallographic preparation. The specimens were made ground flat and polished

and immersed in test irrigant for 5 minutes. Post treatment microhardness values were

evaluated.

One way ANOVA and post hoc Tukey’s tests were used to reveal any significant

differences among and between groups respectively.

Summary

71

The results demonstrated that minimum reduction in smear layer removal was noticed in

Group IV in which the specimen was treated with normal saline. The smear layer

removal score was noticed minimum in Group I in which the specimen were treated with

3% NaOCl for 3 minutes. The smear layer removal score in Group II is less when

compared to Group III and Group IV. The highest value of microhardness was obtained

in control group. When compared with the control group, maximum reduction in

microhardness was noted in Group I in which the specimens were treated with 3%

NaOCl. The minimum reduction in microhardnness were noted in Group IV in which all

the specimens were treated with normal saline. The reduction in microhardness of Group

II is little more when compared to Group III and Group IV.

The order of smear layer removing ability among groups is as follows:

Group I > Group II > Group III > Group IV .

The reduction in hardness among the tested group is as follows.


It can be summarized from the study that the canal irrigations with this chemicals led to

removal of smear layer and structural changes as evidenced by reduction in

microhardness and augmentation in surface roughness. The softening effect of irrigants

on the dentinal walls could be beneficial, as it permits rapid penetration and negotiation

of root canals. MCJ can be regarded as an effective solution for this purpose with lower

reduction of microhardness value, which is a serious concern in case of other popular

endodontic solutions.

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72

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CONSENT FORM

DAPM RV DENTAL COLLEGE

CONSENT FOR EXTRACTIONS AND MINOR ORAL SURGICAL

PROCEDURES

NAME: DATE:

AGE: O.P. NO:

ADDRESS: TEL NO:

I,...................................................................................the undersigned give consent for

extraction procedure which has been explained to me by the Doctor.

I acknowledge that I have answered all the questions about my health and revealed details of

systemic health, allergies, medication, previous treatment etc. and I will not hold my dentist

or any member of staff/student responsible for any error of omissions that I have made during

clinical examination.

It has been explained to me that there are certain inherit and potential risks in any treatment

procedure and I understand that a perfect result is not guaranteed or warranted and cannot be

guaranteed or warranted.

The doctor has explained to me in detail the medication and the postoperative complications

which may arise due to the surgical procedure or anaesthesia and also that the response may

vary from patient to patient.

I give my consent that in the event of any unforeseen complications, I may be shifted to any

hospital for further treatment and I will not hold the dental student and staff responsible for

any damages, liabilities and expenses that will be incurred. I understand that the doctors,

hospital staff and students are acting in good faith and intentions. I also understand that the

students of this institution will be working under the direct supervision of the faculty

members of the department. I give my consent for the use of approved and standardized

procedures and materials for tooth extraction procedures.

I also give my consent for filming, video graphing of the surgical procedures for the purpose

of medical education, records, periodic records and articles, and the use of the extracted tooth

for research purposes.

_________________________ __________________________

Patient’s signature Staff signature

PROFORMA

Sl Specimens Micro Hardness_before Micro Hardness_after SmearLayer score

Group 1 -3% Sodium Hypochlorite(NaOCl)

1 Specimen 1

2 Specimen 2

3 Specimen 3

4 Specimen 4

5 Specimen 5

6 Specimen 6

7 Specimen 7

8 Specimen 8

9 Specimen 9

10 Specimen 10

11 Specimen 11

12 Specimen 12

13 Specimen 13

14 Specimen 14

15 Specimen 15

16 Specimen 16

17 Specimen 17

18 Specimen 18

19 Specimen 19

20 Specimen 20

Group 2 - 6% Morinda Citrifolia Juice(MCJ)

21 Specimen 1

22 Specimen 2

23 Specimen 3

24 Specimen 4

25 Specimen 5

26 Specimen 6

27 Specimen 7

28 Specimen 8

29 Specimen 9

30 Specimen 10

31 Specimen 11

32 Specimen 12

33 Specimen 13

34 Specimen 14

35 Specimen 15

36 Specimen 16

37 Specimen 17

38 Specimen 18

39 Specimen 19

40 Specimen 20

Group 3 - 2% Chlorhexidine Gluconate(CHX)

41 Specimen 1

42 Specimen 2

43 Specimen 3

44 Specimen 4

45 Specimen 5

46 Specimen 6

47 Specimen 7

48 Specimen 8

49 Specimen 9

50 Specimen 10

51 Specimen 11

52 Specimen 12

53 Specimen 13

54 Specimen 14

55 Specimen 15

56 Specimen 16

57 Specimen 17

58 Specimen 18

59 Specimen 19

60 Specimen 20

Group 4- Normal Saline

61 Specimen 1

62 Specimen 2

63 Specimen 3

64 Specimen 4

65 Specimen 5

66 Specimen 6

67 Specimen 7

68 Specimen 8

69 Specimen 9

70 Specimen 10

71 Specimen 11

72 Specimen 12

73 Specimen 13

74 Specimen 14

75 Specimen 15

76 Specimen 16

77 Specimen 17

78 Specimen 18

79 Specimen 19

80 Specimen 20

Comparison of mean Smear Layer Removal Scores between Irrigants using Kruskal Wallis Test


Group 1

Group 2

Group 3

Group 4

Multiple comparison of mean Smear Layer Removal scores b/w different Irrigants using Tukey's

Post hoc Analysis

(I) Groups (J) Groups Mean Diff. (I-J)


P-Value Lower Upper

Group 1 Group 2

Group 3

Group 4

Group 2 Group 3

Group 4

Group 3 Group 4

Comparison of mean Dentin Micro Hardness Values between different groups before immersing

in Irrigants using One-way ANOVA Test


Group 1

Group 2

Group 3

Group 4

Comparison of mean Dentin Micro Hardness Values between different groups After immersing

in Irrigants using One-way ANOVA Test


Group 1

Group 2

Group 3

Group 4

Multiple comparison of mean dentin Micro Hardness b/w groups after immersing in Irrigants

using Tukey's Post hoc Analysis

(I) Groups (J) Groups Mean Diff. (I-J)


P-Value Lower Upper

Group 1 Group 2

Group 3

Group 4

Group 2 Group 3

Group 4

Group 3 Group 4

Comparison of mean Dentin Micro Hardness during Before and After immersion in Irrigants in

each group using Student Paired t test


Group 1 Before

After

Group 2 Before

After

Group 3 Before

After

Group 4 Before

After

Scanned with CamScanner

82

ANNEXURE

Fig 1: Human mandibular teeth used in the study

Fig 2: Decoronation of sample

83

Fig 3: Decoronated samples

Fig 4: Armamentarium used

84

Fig 5 : Irrigants used

Fig 6: Access opening Fig 7: Cleaning and shaping

85

SMEAR LAYER EVALUATION (40 samples)

Fig 8: Final irrigant used for 3 minutes

Fig 9: Sectioning of sample Fig 10: Sectioned sample

86

Fig 11: Stereomicroscope

87

MICROHARDNESS TESTING (remaining 40 samples)

Fig 12: Sectioning of sample Fig 13: sectioned sample

Fig 14: Vertical section of root embedded in resin

88

Fig 15 : Samples embedded in auto-polymerizing resin

Fig 16: Polishing of the root specimen

89

Fig 17: Immersion of the specimen in test solution for 5 minutes

90

Fig 18: Vicker’s microhardness tester

Fig 19 : Evaluation of microhar

91

Table no.2:Comparison of mean Smear Layer Removal Scores between

Irrigants using Kruskal Wallis Test


Group 1 20 1.35 0.49 1 2

<0.001* Group 2 20 1.90 0.79 1 3

Group 3 20 2.50 0.69 1 3

Group 4 20 2.60 0.60 1 3

*Statisticaly significant

Table no.3: Multiple comparison of mean Smear Layer Removal scores b/w different

Irrigants using Tukey's Post hoc Analysis


Mean Diff.

(I-J)


P-Value Lower Upper

Group 1 Group 2 -0.55 -1.09 -0.01 0.02*

Group 3 -1.15 -1.69 -0.61 <0.001*

Group 4 -1.25 -1.79 -0.71 <0.001*

Group 2 Group 3 -0.60 -1.14 -0.06 0.02*

Group 4 -0.70 -1.24 -0.16 0.005*

Group 3 Group 4 -0.10 -0.64 0.44 0.68


Table no 4: Comparison of mean Dentin Micro Hardness Values between different

groups before immersing in Irrigants using One-way ANOVA Test


Group 1 20 64.218 4.021 57.90 70.98

0.84 Group 2 20 63.857 2.336 59.14 67.94

Group 3 20 64.779 3.176 58.14 69.74

Group 4 20 64.274 3.051 58.48 69.24

Group1- 3% NaOCl, Group 2- 6% MCJ, Group 3- 2% CHX, Group 4- Normal Saline

92

Table no.5: Comparison of mean Dentin Micro Hardness Values between different

groups After immersing in Irrigants using One-way ANOVA Test


Group 1 20 52.172 2.665 47.43 59.53

<0.001* Group 2 20 57.322 2.063 53.76 61.30

Group 3 20 59.979 3.950 53.31 66.35

Group 4 20 63.034 3.298 56.16 68.12

*Statistically Significant

Table no.6: Multiple comparison of mean dentin Micro Hardness b/w groups after

immersing in Irrigants using Tukey's Post hoc Analysis


Mean Diff.

(I-J)


P-Value Lower Upper

Group 1 Group 2 -5.150 -7.705 -2.595 <0.001*

Group 3 -7.808 -10.362 -5.253 <0.001*

Group 4 -10.862 -13.417 -8.307 <0.001*

Group 2 Group 3 -2.658 -5.212 -0.103 0.04*

Group 4 -5.712 -8.267 -3.157 <0.001*

Group 3 Group 4 -3.055 -5.609 -0.500 0.01*

Table no.7: Comparison of mean Dentin Micro Hardness during Before and After

immersion in Irrigants in each group using Student Paired t test


Group 1 Before 20 64.218 4.021 12.047 <0.001*

After 20 52.172 2.665

Group 2 Before 20 63.857 2.336 6.536 <0.001*

After 20 57.322 2.063

Group 3 Before 20 64.779 3.176 4.800 <0.001*

After 20 59.979 3.950

Group 4 Before 20 64.274 3.051 1.241 <0.001*

After 20 63.034 3.298

93

GRAPH 1 : MEAN SMEAR LAYER REMOVAL SCORE BETWEEN IRRIGANTS


BETWEEN DIFFERENT GROUPS BEFORE IMMERSING IN IRRIGANTS

94


BETWEEN DIFFERENT GROUPS AFTER IMMERSING IN IRRIGANTS


BETWEEN DIFFERENT GROUPS BEFORE AND AFTER IMMERSING IN

IRRIGANTS

95

THE STEREOMICROSCOPIC IMAGE OF ROOT CANAL SPACE FOR SMEAR

LAYER AT 20X MAGNIFICATION AFTER IRRIGATING WITH TEST

IRRIGANTS.

fig 20: sodium hypochlorite (NaOCl)

fig 21: morinda citrifolia juice (MCJ)

96

Fig 22: chlorhexidine gluconate (CHX)

fig 23: saline

COMPARATIVE EVALUATION OF DIFFERENT ENDODONTIC …

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