Micro Preparations 1

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Micropreparations

Surendra


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Introduction

Aims and objectives of restorative dentistry

Need for micropreparations

- Slogans

- Changes in concepts of treatment of caries, materials Benefits of conserving tooth structure

Requirements of micropreparations

Caries

- etiology

- detection

- treatment

- instruments

- materials

- maintenance

- re evaluation

Ultraconservative preparations Treatment of proximal caries

sonoabrasion

Magnification

Microsurgery

Conclusion References


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Introduction


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Aims and objectives of restorative

dentistry

Aims

- prevention

- interception

- preservation

- restoration

Objectives

- provision of access

- removal of caries and tissue weakened by caries

- production of biologically satisfactory shape

- production of a mechanically satisfactory shape


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Need for micropreparations


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Slogans

Extension for prevention

Cutting for immunity

Need for access

Conservative approach- Enameloplasty

- Prophylytic odontomy

- pit and fissure sealant application Minimal intervention

Microdentistry


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Changes in concepts

Blacks concept

Conservative approach

Micro dentistry


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Changes in materials

Amalgam

Gold restorations

Improvements in amalgam

absence of adhesion

Pins

Adhesive materials

Composites

Glass ionomer cements


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Benefits of conserving tooth

structure

Opportunity to develop recurrent caries is

minimized

Incidence of early restoration failure is

minimized

Incidence of tooth fracture is decreased

Pulp vitality is retained throughout the life


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Caries


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Methods of caries detection

Radiographs

Clinical visual tactile

Electric conductance

Fiber optic transillumination Quantitative laser fluorescence

Diagnodent

Difoti

Chemical dyes Electronic caries monitor

Impression materials


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Classification of caries

Gv black

New cavity classification


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Comparision of G V Blacks and new

classfication

- site 1 > size 2,3,4 - blacks class1

- site 2 > size 2,3,4 - blacks class2

- site 2 > size 2,3 - blacks class3

- site 2 > size 4 - blacks class4

- site 3 > size 1,2,3,4 - not mentioned


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Changes in trends in caries

Classification

G V Black

New classification G J Mount


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Conservative operative management

strategies

Ultra conservative cavity preparations

Ultra conservative sealed restorations

Air abrasion

Preventive resin restorations fissurotomy


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Air abrasion

Advanced beam technology, micro abrasive technology

Robert black- 1943

Airdent unit, ss white 1953

FDA approved 1982- microprep, kcp series

Compressed air 40 to 140 psi

Aluminium oxide particles 20 to 50 microns

One inch above tooth surface

Current recommendations

- access to the lesion with air abrasive unit, cariesdetection dye, excavation with small round burs


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Clinical uses

-remove debris

- diagnose and treatment of pit and fissures

- cleaning

Advantages

- in preparation of initial occlusal and cervical

lesions- management of approximal lesions

Disadvantages

- inability to remove caries

- chronic respiratory disorders

- very expensive

- require skill


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Preventive resin restorations

Simonsen 1977

round bur, 331/2 bur

advantages :

- less traumatic to the tooth

- minimally invasive to the tooth


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Fissurotomy

Def ; the process of opening or wideningtortuous posterior grooves and or fissuresas a prelude to the placement of sealants

or resin restoration. Fissurotomy system- ss white

original

micro NTFmicro STF

Goals


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Other systems

Thin and narrow diamonds for minimal invasive

cavity preparation (brasseler)

Smart prep


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Sono abrasion

Frequency 6.5khz

3.5 bar air pressure for cavity preparations,lower pressure for finishing the margins

4 different working tips

- angulated type

- the half torpedo- longitudnally sectioned torpedo

- small half sphere

- large half sphere

A l t d t (0 8 )


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Angulated type (0.8mm)

- has cylindrical or conical working end with

circular diamond coating and a flat smooth non

cutting front end

- used for intracoronal and extracoronal tunnel

preparations

The half torpedo


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The half torpedo

- has uncoated working side, non coated beveled circumferential edge and

a concave working side

- used to cavosurface beveling of cl2, cl3 @ ci4 adhesive and cast gold

preparations.- marginal beveling of crown and veneer preparations

Hemi spherical blade

- convex diamond coated tip

-direct access preparations (especially when enamel is already

demineralized)

- in preparation and cavosurface beveling of cl2 & cl3 cavity designs


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Internal approximal cavity preparation


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Internal approximal cavity preparation

The Micro chip approximal cavity preparation

Box preparations

- the mini box approximal cavity preparation

- the full box approximal cavity preparation Simple preparations


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Internal approximal cavity

preparation

Other names tunnel preparation

- internal fossa preparation

- internal oblique preparation- internal preparation


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Micro chip

This procedure is usually followed when

removal of porous enamel is required

Also used when fractures in enamel wall

are found to extend own from the marginal

ridge to porous region


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The mini box

Design is Similar to slot restoration

-- conservative design

-- simple box


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simple

Same as simple design by Marzouk


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Magnification

Methods

- loupes- surgical head lamps or conventional surgical telescopes

- surgical microscopes

Advantages

- wider fields

- variable magnifications

- better depth of focus- coaxial illumination

Disadvantages

- very expensive

- visual dislocation even with moderate head movements

- loss of visual field at higher magnifications

- skill

Types of magnification

low magnification - 2.5x to 8x

mid range magnification - 10x to 16x

high magnification 20x to 30x


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Sugical microscopes

advantages

- minute details- fewer or no radiographs

- videorecording possible

- stress reduction- communication with referral dentists


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Micro surgeryDef: is defined as a surgical procedure on exceptionally small and

complex structures with an operation microscope

The triad of endodontic microsurgery

Advantages


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Advantages

- small osteotomies and shallow bevels

- under high illumination and magnificationbetter visualization of anatomic details


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Differences b/w traditional and

microsurgery

Traditional

1. Difficult

2. Large >10mm

3. None4. Large 450

5. Nearly

impossible

6. Approximate

7. imprecise

Microsurgery

1. Precise

2. Small


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Classification

Class A the absence of periapical lesion butunresolved symptoms after non surgical approacheshave been exhausted

Class B the presence of a small periapical and no

periodontal probe depth Class C presence of a large periapical lesion

progressing coronally but without a periodontal pocket

Class D same as class c but with a periodontal pocket

Class E

a periapical lesion with an endo-periocommunication but no root fracture

Class F a tooth with an apical lesion and completedenudation of apical plate


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Instruments

Microexplorer Microblade

Micromirrors

Kp retractors

Stropko drier

Impact air 45 handpiece

H161 lindemann bone cutting bur

Mini endodontic curettes

Mini jacquettes

Minirounger

Mini bone file

Microplugger

Retro fill carriers

Laschal microscissors

Castro veigo needles


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Diagnostic instruments:

Compared with a conventional mouth mirror


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CM-1 5mmRound

CM-2 3mmRound

CM-3 Medium Oval

CM-6 Large Oval

Micro mirrors with sapphire surfaces makes them scratch proof !!


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Large oval micro mirrors used to view root end

preparations in the molar region


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Conventional scalpels

Micro scalpel (double edge)

R t t


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Retractors

Comparison with conventionalretractors


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conventional microsurgical

Area specific retractors

Micro needle holders


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Micro needle holders

CASTROVIEJONEEDLE HOLDER

DERF NEEDLE HOLDER


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Procedure

Identification of the apex in the intact buccal

plate

Ostetomy size

Inspection of resected root surface under themicroscope

Bevel angle

Isthmus identification and preparation Ultrasonic root end preparation

Retrograde filling


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IsthmusDef : a narrow connection between two root

apices and contains pulp tissue (kim)

green (1973) isthmus as corridor between tworoots.

Pineda (1973) phenomenon as lateral canalsvertucci (1984) stated isthmus was ananastomosis

Weller (1995) as a narrow, ribbon shapedcommunication between two roots canals thatcontains pulp tissue


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Classification

Type 1 either two or three canals with nonotable communications

Type2 -- 2 canals that possessed a definiteconnection between the two main canals

Type3 -- differs from the latter only withpresence of 3 canals were also included in thiscategory

Type4 when canals extended into the isthmus

area Type5 as a true connection or corridor

throughout the section


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Ultrasonics

Ultra sonic tips & needles

- carr tips

- kim surgical tips

Carr tips

ct1 max& mand anterior

ct2 posterior teeth

ct3 posterior teeth

ct4

ct5 max & mand anterior

Kim surgical ultrasonic tips


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Kim surgical ultrasonic tips

- kis 1 --- mand anterior & premolar

- kis 2 --- max anterior- kis 3 --- posterior teeth

- kis 4 --- lingual apex of molar teeth

- kis 5 --- posterior teeth

- kis 6

Ultrasonic KiS tips for root-end cavity


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p y

preparation


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Ultrasonic root end preparation

Developed to address and solve the majorinadequacies of the conventional bur typeretropreparations

Creating tracking groove with CX- 1 explorer With water off use the CT5 or UT5 to deepen the

tracking grooves

With water on use the CT2,CT3 & CT5 to

deepen the preparation to its full length Flatten the floor of the preparation with CT1 or

UT1


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Root end filling materials Commonly used amalgam

- GIC- zinc oxide eugenol cement

- IRM

-super EBA

- Cavit

- Guttapercha

- Composite resin Less commonly used gold foil

- zinc phosphate cement

- diaket

- teflon

- titanium screws

Potential materials MTA- cyano acrylates

- apatite cement

- gallium alloy

Combination of different materials double seal

- sandwich seal


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conclusion


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References

DCNA incipient and hidden caries, oct 2005.

DCNA restorative dentistry, 2000

Text book of Microsurgery , kim 1st Ed

Art and science of operative dentistry, strudevant

Adhesion Jean Rouselt

Operative dentistry -- Vimal Sikri

Advances in operative dentistry

Product profile fissurotomy kit, jol fam dent, 2005: 7.

Operative dentistry, Baum

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