Strategies

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Ove A. Peters, DMD MS PhDDiplomate, American Board of Endodontics

Contemporary Strategies inRoot Canal Treatment

January 17, 2013Seattle WAWashington State Association of Endodontists

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§ 1917- access, cleaning & shaping, gutta percha, radiographs- even some instruments look exactly the same as today

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§ “Success/Failure” concepts - comparison to implant data (“retention”) - numbers may change with advent of CBCT

§ Overall health considerations - data not clear regarding cardiovascular events and endo - emergence of host defense as an important factor

§ Treatment modalities - conventional root canal, improved version - biologic treatment, such as regenerative endodontics

Items for Considerationn Introduction

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n Discussion

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Follow-up studies (2000-2012)

“Suc

cess

” ra

te (%

)

n = 52

S. Friedman

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100

Initial Treatment

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Initial Treatmentn = 11

Hea

led

(%)

Current best evidence

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gren

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l. 19

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Ørs

tavi

k 19

96

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97

Wei

ger e

t al.

2000

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endi

ng e

t al.

2005

Hos

kins

on e

t al.

2002

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i et a

l. 20

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ers

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et a

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11

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ucci

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S. Friedman

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Alternative Treatments

www.iti.ch

n Introduction

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n Discussion

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Which Are Key Strategies?§ Access! - ideal configuration BUT “do not harm” - prevent preparation errors, e.g., ledges etc.

§ Cleaning and shaping! -!balance size, antimicrobial effect, debris production - irrigation efficacy, antimicrobials

§ Obturation! -!occlusion of space and leakage pathways

§ Follow-up care! -!understand success and failure - select retreatment vs surgery vs implant

n Introduction

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n Discussion

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Key 1: Access§ Basics

§ Step-by-Step determined by! - size of pulp chamber! - shape of pulp chamber! - design of root canal system - demands of instrumentation technique

n Introduction

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How Are We Doing?

Case by Dr Helmut Walsch

§ We are able to do beautiful work

n Introduction

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§ Law of centrality (1)! -!pulp chamber floor is centered at the CEJ

Laws of Orifice Location

Wilcox 1989

n Introduction

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n Discussion

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Tooth Development

D’Souza 2002

§ Programmed and detailed succession of events! -!morphogenesis and differentiation

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Bjørndal 1999

Geometrical Principles§ Outer root surface follows cross sectional pulp shape! -! remember morphogenesis and differentiation!

CLINICAL HINT: Track root contour with explorer

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Straight-Line Access§ Instruments are constrained cervically! -!WL shortens during procedure

- preparation is affected by coronal tension

§ Rotary instrument fatigue more! -!coronal curves are more dangerous

- should go straight into middle 1/3

§ Transition from chamber to canal! -!cutting NiTi: lateral, push

- US tips: sanding, digging, troughing, undercutting- SS White Access burs

n Introduction

n Strategies

n Discussion

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Searching for Evidence

§ For practical reasons: - 1/3 literature, 1/3 clinician, 1/3 patient - searched databases, reference lists

§ Issues with written evidence! -! levels of evidence: clinical trials vs bench top

- “biological plausibility”, “surrogate outcomes”- room for interpretation, conflicting results

n Introduction

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n Discussion § Evidence-based dentistry….! ... is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. Sackett 1996

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Searching for Evidence§ www.ebd.ada.org - large compilation of access portals and materials - an attempt to help general dentists

§ Some centers have their own collection - San Antonio: CATs - Detroit: evidence-based endodontics

§ Search for original data - pubmed, Cochrane group and others - hand search from textbooks and reviews

n Introduction

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Key Evidence

§ Clinical! - no studies identified

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§ Overall size! - dentin removal equals loss in stiffness - largest contributor MOD cavity (63%) vs access (5%)

Reeh 1989Messer et al

§ Overall shape! -!dictated by anatomy, tooth development - visibility of all orifices Wilcox 1989

Krasner & Rankow 2004

§ Crown down strategy! - better tactile feedback: working length determination - essential for many rotary instruments

Stabholz 1995

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The Classics

Reeh 1989

§ Stiffness and fracture load depend on preparation extent! -!most tests address catastrophic failure load

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What Is Important?§ Be centered! -!based on: laws of symmetry

§ Understand the long axis! -!based on: “Do not harm”

§ Find all orifices! -!based on: microbiological principles

§ Provide straight-line access! -!based on: engineering principles

§ All of the above! -!based on: common sense

n Introduction

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Access Modified

from Ingle’s Endodontics 6th ed

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Key 2a: Cleaning & Shaping§ Overall shape! -!“Schilder-type” shape! -!“standardized” shape

§ Apical end point ! - location and determination of “length”

- patency a goal/dangerous?

§ Apical size! - small: conserving dentin, providing tapered seat - larger: providing more access for irrigants

n Introduction

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n Discussion

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”... the Root Canal Must be Shaped

so That a Tapering Funnel is

Created With its Narrowest

Diameter at the Periodontal

Ligament and the

Largest at the Coronal Opening.“

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Schilder 1967

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Allison DA, Weber CR, Walton RE (1979)

§ Aim! -! to investigate the effect of two methods of canal enlargement on apical seal

§ Methods! -! 46 teeth, 4 controls, 22 specimens prepared to .02 taper (standardized) &! ! 20 specimens to .10 taper (step back)! -! obturation with lateral compaction, ZOE sealer! -! leakage evaluated using 45Ca & micro-radiography! ! teeth were immersed to allow apical and coronal penetration of isotope! -! spreader insertion depth recorded

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The influence of the method of canal preparation on the quality of apical and

coronal obturation. J Endodon, 21:561-568

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§ Discussion! -! for lateral compaction, spreader penetration is correlated with leakage! ! deeper penetration possible with .10 taper compared to .02 taper! -! spreader should penetrate to 1 mm or less

§ Results! -! .02 taper group: mean spreader penetration was to 3.5 mm (0.5 - 5 mm)! ! 5/22 teeth allowed deep spreader insertion (+2 mm) and had no leakage! ! 6/22 had gross leakage (> 4.8 mm) and 11/22 had leakage to app. 3.6 mm! -! .10 taper group: mean spreader penetration was to within 1mm (20/20)! ! no significant leakage overall! ! 2/20 had leakage to > 1 mm! -! coronal aspect was sealed to isotopes in all cases

Allison et al JOE (1979)n

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Why Small Is Beautiful...

Elin A.C. Peters, 6m

n Introduction

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Why Small Is Beautiful...

From: Buchanan 2001From: Card et al 2002

A MAF 60, 80 B MAF 20

n Introduction

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Increased Apical Enlargement

§ Experimental data overall! - numerous variables, unclear outcomes - “complete” canal preparation unlikely

§ One conclusion! - “...it may be recommended to keep the apical size of curved canals as minimal as possible provided that a sufficient irrigation is feasible.”

El Ayouti, 2011

n Introduction

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n Discussion

§ Clinical data - mixed results, very difficult to tease out real information - a rare prospective study suggested larger sizes

Raj Saini, 2012

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Nair PNR, Henry S, Cano V, Vera J (2005)

§ Aim! -! to assess the microbiological status after single visit root canal treatment

§ Methods! -! 16 lower molars with periradicular periodontitis were treated with K-Files! ! or LightSpeed (apical sizes 25 and 40, respectively) and lateral compaction! -! irrigation was with 5.25% NaOCl and 17% EDTA! -! immediately after root canal filling, mesial apices were resected! -! histological evaluations were done on LM and TEM levels! -! positive and negative controls were teeth extracted due to periradicular! ! periodontitis and orthodontic reasons, respectively

Microbial status of apical root canal system of human mandibular first molars

With primary apical periodontitis after “one-visit“ endodontic treatment

Oral Surg Oral Med Oral Path Oral Rad Endod, 99: 231-252

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Mesiobuccal K-file& MAF 25, mesiolingual MAF 40 (?)

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C&S Update

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§ Discussion! -! it appears that canals treated in a single visit such in this study cannot be! ! rendered bacteria-free, regardless of the apical size (but it is unclear if! ! multiple visits could have rendered canals sterile from this study)! -! the presence of immune cells suggests chemotaxis and a fluid phase in ! ! some phases of pulpal necrosis, allowing immune cells to be active

§ Results! -! 14/16 treated canals harbored bacteria in their root canal systems! -! 8 of the specimens each had bacteria in the canal enlarged with K-Files! ! to size 25 and with LightSpeed to size 40! -! 11/16 mesial roots had an isthmus region, 10 of which were contaminated ! ! with microorganisms, as were 6 of 8 accessory canals! -! numerous PNMs were found in the isthmus region

n Nair PNR OOOE (2005)

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§ Length determination! - which principle, landmarks? - how to determine?

§ “Best practices”! -! instrument and case selection - clinical usage parameters

n Introduction

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Further Considerations

§ Preparation errors - block and ledge - role of instrument fracture

Gorni 2004

Parashos 2006

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n Apex “Locators”

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Clinical Practicen Introduction

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How did I get there...n Introduction

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Pettiette MT, Olutayo Delano E, Trope M (2001)

§ Aim! -! to compare effects of RCT with 2 types of files on changes in bone density

§ Methods! -! 60 molars treated by 30 undergraduate students were followed for 1 yr! -! all teeth were initially associated with an apical radiolucent area! -! treatment was with either stainless steel or NiTi K-files to similar shapes in! ! both groups and all other peri-treatment variables were similar! -! individualized bite blocks were fabricated to allow subtraction radiography! ! and densitometric measurement of changes in apical bone architecture! -! grey levels were enumerated for the apical and a normal area in each case! -! corresponding ratios were calculated and compared with Fisher’s tests

Evaluation of success rate of endodontic treatment performed by students with

stainless-steel K-files and nickel-titanium hand files. J Endodon, 27: 124-127

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§ Discussion! -! for novice clinicians, the potential of NiTi hand files to prevent preparation! ! errors results in dramatically improved clincal prognosis (OR=5, CI 1.3,20)! -! the authors concede that skilful operators would have had a better chance! ! to avoid such errors with stainless steel instruments

§ Results! -! 40 teeth were available for 1yr recall, with no difference in initial scores! -! success was associated with a grey level change of app 78% in NiTi cases! ! and 45% in stainless steel cases; failures, indicated by grey level decrease,! ! were 20% (NiTi) and 55% (stainless steel), respectively! -! success probability was 15/19 with NiTi and 9/21 with stainless steel! -! this difference was significant and was associated with a higher number! ! of procedural errors in the stainless steel group (i.e., strip perforations)

Pettiette MT J Endodon (2001)n

Phase II Apical ShapingPhase I Coronal Flaring

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Staged Preparationn Introduction

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The ProTaper Systemn

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0

30

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2001 2003 2005 2007 2009 2011 2013*

ProTaper Publications

Ruddle et al 2001

Berutti et al 2003Peters et al 2003a,b

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§ Hand files! -!various sizes - initial scouting and patency, WL - canal gauging

Supplemental Instruments§ Orifice relocation with Sx

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PathFiles§ Directions for use! - loose size #10 to WL - passive action, following the canal path - 300rpm

No. 1 = #13

No. 2 = #16

No. 3 = #19

Often NOT

Needed

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ProTaper Next History

2013

2006

2001

Since the beginning of modern day endodontics, there have

been numerous concepts, strategies, and techniques for

preparing canals. Over the decades, a staggering array of

files has emerged for negotiating and shaping canals. In

spite of the design of the file, the number of instruments

required, and the surprising multitude of techniques advo-

cated, endodontic treatment has been typically approached

with optimism for probable success.

The clinical endodontic breakthrough was progressing from

utilizing a long series of stainless steel (SS) hand files and

several rotary Gates Glidden drills to integrating nickel

titanium (NiTi) files for shaping canals. Regardless of the

methods utilized, the mechanical objectives for canal prepara-

tion were brilliantly outlined almost 40 years ago by Dr.

Herbert Schilder.1 When properly performed, these mechanical

objectives promote the biological objectives for shaping

canals, 3-D disinfection, and filling root canal systems (Figure 1).

The purpose of this article is to identify and compare how

each new generation of endodontic NiTi shaping files served

THE SHAPING MOVEMENT

5TH GENERATION TECHNOLOGY

by Drs. Clifford J. Ruddle, Pierre Machtou and John D. West

DENTISTRY TODAY April 2013

Figure 1a. A µCT image

of a maxillary central

incisor tooth demonstrates

a root canal system with

multiple portals of exit.

Figure 1b. A pretreatment radiograph reveals

an endodontically failing anterior bridge abut-

ment with a draining fistula.

Figure 1c. This post-op retreatment image

emphasizes that shaping canals promotes 3D

cleaning and filling root canal systems.

Figure 1d. A 25-year radiographic recall image

demonstrates osseous healing.

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§ Opinion paper! -!clinical handling described - cases presented - rationale given

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WLradiograph

Pre-opradiograph

Routine Root Canals (SB, 13)

ConeFit

Final radiograph

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Key Evidence

§ In vitro studies! - several thousands of papers - CAVE: “biologic plausibility” - many clinical outcomes inferred

n Introduction

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n Discussion

§ Clinical! - few prospective studies - good analyses from retrospective studies

Ng 2011Ricucci 2011

§ Classics! - canal preparation needed, not sufficient - overall tapered shape is recommended

Byström 1981

Schilder 1974

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Ng Y-L, Mann V, Gulabivala K

§ Aim! -! to investigate factors influencing the periapical status after RCT

§ Methods! -!more than 1000 patients and 2200 roots were followed for 2-4 years - data was obtained prospectively for pre-and perioperative factors such as initial presence of p.a. lesion, presence of sinus tract, achieving patency, using EDTA, CHX, root filling extrusion, satisfactory coronal restoration - the proportion of roots with complete periapical healing was determined - robust statistical methods were used to determine odds ratios for each factor taking clustering into account

A prospective study of the factors affecting outcomes of nonsurgical root canal

treatment: part 1: periapical health. Int Endod J, 44: 583-609

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§ Discussion! -! very large and well controlled prospective study of resident treatments - author acknowledges bias brought in by the specific setting - more research is required to more directly establish best practices, however common sense and classic studies continue to inform clinical endodontics

§ Results! -! based on review of ~1500 teeth & ~2500 roots overall success was ~80-83% - almost all lesions that ultimately healed did so within two years - these pre-operative factors were significantly associated with success: pulpal status, absence (and small size) of p.a. lesion and of sinus tracts - some perioperative factors were significantly associated with success: patency (+), long fill (-), use of CHX (-), use of EDTA (+) - several well-established clinical strategies not associated (e.g. 5.25% NaOCl)

Ng Y-L Int Endod J (2011)n

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Orifice Modification§ Hard tissues may impede direct access! -!detect and remove

- without iatrogenic damage

n Introduction

n Access

n Shaping

n Disinfection

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The Logic Of Stages Prep

McSpadden 2008

§ We have adequate concepts! -! just need to apply them in the clinic

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Key 2b: Cleaning & Shaping§ Select an adequate irrigant (-sequence)! -!NaOCl is essential! -! interactions exist among irrigants; substrate

§ Evidence! -!clinical outcomes studies are sparse

- perhaps different cases require specific strategies

§ Deliver the irrigant to the site! - shape adequately, remove debris successfully - provide irrigant flow

n Introduction

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n Discussion

Svensäter 2004

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Biofilms Visualized§ Conventional microscopy! - Brown Brenn stain

n Introduction

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n Discussion

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Presence and Removal§ Biofilms are present in root canals! - standard methods are effective...but not completely

- activated irrigation recommended

§ Biofilms may be present extraradicularly! - possible but not frequent

- may be associated with refractory lesions: surgery

§ Biofilms may be present in retreatment! - typical strategy: enlargement, irrigation, medication

- inaccessible canal spaces- development of resistant strains, persisters

n Introduction

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n Discussion

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Sodium Hypochlorite Facts§ Excellent disinfection capacity! -!household bleach (in fact app. 6-7%, ref. Chlorox)! -!available chlorine determines efficacy

§ Significant toxicity! -!solution expressed into tissue leads to necrosis! -!DO NOT LOCK needle in canal

§ Tissue dissolving properties! -!depend on temperature! -!are self limiting depending on concentration

n Introduction

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n NaOCl Incidents

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n Removing Smear Layer

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EDTA Facts§ Minimal disinfection capacity! -! insignificantly better than saline! - believed to allow access beyond smear layer

§ Side effects! -!may lead to exaggerated demineralisation! - has potential to greatly suppress NaOCl action

§ Tissue dissolving properties! -!dissolves dentin by chelation! -!effect greatest at neutral pH, typically 17% conc.

n Introduction

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Chlorhexidine Facts

§ Side effects! -!NaOCl and CHX give rise to reddish precipitate! -! this material may be toxic or even carcinogenic

§ Concentration and galenics! -! reports available from 0.12 to 2% (-5%)! -!gel vs liquid vs impregnated gutta percha points

§ Disinfection capacity beyond NaOCl! -!seen as beneficial in retreatment! - may not provide any clinical benefit

Stuart 2006

Manzur 2007

n Introduction

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Activated Irrigation (PUI)§ Effect of ultrasonically activated irrigation I! - no effect: no more bacterial reduction

- no effect: incomplete smear layer removalSequeira 1997

Cheung & Stock 1993

§ Effect of ultrasonically activated irrigation II! - positive effect: bacterial reduction

- positive effect: removal of smear layerHuque 1998

Cameron 1983

§ Preparation errors! - use of cutting ultrasonically activated instruments may

lead to undesirable canal shapes Stock 1991Mayer 2002

vd Sluis 2007n Introduction

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Temperature & Active Irrigation

Zeltner 2009

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Exotic Systems§ Laser-assisted irrigant activation (PIPS)! - mechanical and streaming effect of pulsed laser to

distribute common or novel irrigation solution- no thermal effect- currently under investigation

§ Pulsed plasma probe! - plasma: gas mixture (99% He & O2) flows through a

nozzle connected to a high voltage generator (10kV)! - short pulses (100ns) of reactive gas eliminate biofilm

- currently under investigationJiang et al 2009

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Activation of Irrigants§ “Photon-initiated photoacoustic streaming” ! - uses pulsed laser to activate deposited irrigant - no thermal effect - may be efficient against biofilms

A B C

0

10

20

before after

Positive SamplesControlUltrasonicsPIPS

DiVito 2010

n Introduction

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Key Evidencen Introduction

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n Discussion § In vitro! -!many studies addressing bacterial killing and soft tissue digestion, recently anti-biofilm effects

Byström 1981

§ Clinical! - little specific evidence for a particular irrigant over another, still a good rationale for NaOCl and EDTA

Ng 2011

§ In situ! - several groups use teeth in patients that will be extracted or sampled

e.g, Nusstein group

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What About “Single-Visit?n Introduction

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n Discussion § Initially...! -!was taught Scandinavian strategy and Ca(OH)2 - evidence appeared to be acceptable

§ In California:! - patients clearly prefer single-visit

§ Currently....! - yes if pulpitis and enough time - no for Re-RCT and infected canals & symptoms

§ In Italy:! - yes with optimal disinfection to avoid leakage

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Sathorn C Int Endod J (2005)n

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For The Time Being...§ Canal instrumentation! - as effective as possible, removal of 100µm recommended

§ Irrigation! - eliminates planktonic bacteria in main canal

- may be effective in detaching biofilm

§ Activation! - ultrasonics best supported by evidence

- other methods may be forthcoming

§ Constraints! - inaccessible canal spaces

- development of resistance

n Introduction

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Key 3: Obturation§ Benefit vs harm! -! is an obvious way to demonstrate proficiency

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Klevant FJH, Eggink CO (1983)

§ Aim! -! to compare outcomes in cases with and without root canal obturation

§ Methods! -! 86 and 336 teeth were treated as experimental and control groups! -! the control teeth were chemo-mechanically prepared and obturated! -! no obturation was done in the experimental group, both were temporized! -! obturation was only done after negative culture! -! radiographic follow-up was done over 2 yrs, using a 6-step scale! -! groups were compared using chi-square tests

The effect of canal preparation on periapical disease. Int Endod J, 16:68-75

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§ Discussion! -! in spite of no obturation, healing occurred in many cases! -! there was recontamination in 15% of the unfilled cases

§ Results! -! experimental group: number of Rx-negative cases increased significantly,! ! cases with large lesions were significantly reduced, rarely positive ! ! cultures during the course of the treatment! -! control group: also significant reduction of Rx positive cases, different! ! situation (better) initially than in the experimental group! -! success was better in short-filled than in “long” or “flush” cases

§ My conclusion! -! obturation, and its quality, are important but no prerequisites for healing

Klevant FJH Int Endod J (1983)n

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Pre-opradiograph

Casehistory

Finalradiograph

Retreatment (AS, 06)n

2yrfollow-up

- 10 yr old fill- slight swelling- New restoration planned- very motivated patient

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§ Material & Methods! -!narrative review of literature

- case review of 493 specimens obtained by extraction or surgery

- routine H&E stains as well as Brown Brenn was done

- special attention was paid to tissue and substances in lateral canals

and apical ramifications (LC/AR)

J Endod 2010, 36:1-15

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J En

dod

2010

, 36:

1-15

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Role of Accessory Anatomy

§ Fate of tissue! - tissue follows fate of main canal tissue - LC/AR content partially removed by cleaning & shaping

§ Filling of accessory spaces! - radiographically filled canals: histologically incomplete - inflamed tissue and bacteria are also present

§ Clinical conclusion! - “It appears that strategies other than finding a technique that better squeezes sealer or gutta-percha within LC/AR should be pursued...”

RIcucci, 2010

n Introduction

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n Discussion

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New in Obturation

§ EndoSequence (Brasseler)! - part of ActiveGP, special coated points adhere to sealer - overall little research into outcomes, a single-cone fill

§ Gutta Core (Dentsply Tulsa)! - modified gutta percha replaces plastic carrier - little research available, handles similar to Thermafil

§ Cordless heating devices (various companies)! - both heated pluggers and GP extruders

§ Flowable materials and their application! - experimental MTA derivatives and others

n Introduction

n Biology

n Technology

n Discussion

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Bioceramics§ Osteoconductive materials - questions about setting time - intended for single cone obturation - no definitive conclusion possible at this time

Loushine 2011

n Introduction

n Biology

n Technology

n Discussion

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Key Evidence

§ Others! - temperature measurements, homogeneity etc - sealer chemistry and biocompatibility

n Introduction

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n Discussion § In vitro! - multiple leakage studies in various models, clinical impact questionable

Zehnder 2012

§ Clinical! - Toronto study, adjunctive observation in others - overextension appears to be negative

Sjögren 1990Ng 2011

RIcucci 2011

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Adverse Outcomes§ Overfill / Overextension may cause! -! (endodontic) failure! -!nerve lesion, fungal infection etc.

n Introduction

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n Discussion

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n A Chain of Events

Instruments

Rubber dam

Restoration

Disinfection

Access

Immune system

Medication

.....

n Introduction

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n Discussion

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Treatment Potential§ Case 1! - 33yr old patient - 4 week old crown

deep pocket #8

§ Case 2! -!85 yr old patient

- sinus tract, no marginal bone loss

n Introduction

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n Discussion

§ Case 2! -!85 yr old patient

- periapical sound tissues at 12m

§ Case 1! -!33yr old patient

- periapical sound tissues at 6m

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Treatment Potentialn Introduction

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n Discussion

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Key 4: Follow-up Care§ Detect failing root canal treatment! -! tools: recall, p.a. film, CBCT! -!clinical impression

§ Toolkit! -!have the clinical skill set to manage retreatment

§ Decisions: treat if needed! - individual decision based on the merit of the case - non-surgical, surgical endo, implant

n Introduction

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Radiographic Successn

§ Cumulative healing! - looking at healed cases only

- if it has not healed after 1 yr,

chances are less that it will

6m outcomes less predictive

- if no healing after 4 years,

it will likely never heal

§ Summary! -!CBCT is more likely to detect previously hidden pathosis - the size of a existing lesion appears smaller on conventional films - there is an increased radiographic dose with CBCT use - perhaps studies into treatment modalities should use CBCT to determine outcomes

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Int Endod J 2011, 44: 887-888

Current Discussion

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CBCT Healing Assessment

§ Potential impact on success rates! -! current numbers may be not valid! -! better discrimination for different treatment modalities

§ Higher sensitivity (clinical cases)! -! p. a. films reveal~30% with lesions! -! small FOV CBCT reveal ~65% with lesions

Estrela 2008

§ Better accuracy (dog study /w histology)! -! p. a. films correct in ~78% of cases, CBCT in ~92%! -! sum of true positives and true negatives

Da Silva 2009

n Introduction

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n Discussion

§ Healing assessment! -!CBCT is sensitive tool - likely to detect significantly more lesions compared to P.A. films

Cone beam computed tomography

and other imaging techniques

in the determination of

periapical healing

CHRISTINE I. PETERS & OVE A. PETERS

To be able to determine if endodontic treatment of apical pathosis is successful or not, healing of lesions is

followed up by radiographic imaging. This can be done by observing changes in apical radiolucencies. Recently,

cone beam computed tomography (CBCT) has been introduced as a method of gaining an unabridged view of

dental anatomy, thus eliminating some of the most prevalent problems, such as superimposition and distortion.

CBCT reduces false diagnosis and is rapidly replacing other radiographic techniques in diagnosis, quality control

of treatment methods and techniques, and outcome assessment. Healing assessment using conventional and newer

three-dimensional imaging includes, but is not limited to, periapical osseous lesions, conditions of the maxillary

sinus, status after endodontic surgery, hard tissue deposition in regeneration procedures, and horizontal root

fractures. Due to a low predictive value of two-dimensional periapical radiographs to distinguish between

periapical disease and health, future assessment of endodontic treatment efficacy may include 3D imaging from

small field-of-view CBCT units.

Received 29 September 2012; accepted 18 November 2012.

Introduction

Endodontic disease has been characterized by the

presence of periapical inflammation (1). The

occurrence of disease can remain unnoticed for

prolonged periods of time or a patient in pain may seek

dental care. Clinically, the existence of apical pathosis

may be detected by sensitivity to biting or percussion,

but asymptomatic apical periodontitis frequently does

not elicit such a response. Symptomatic apical

periodontitis is caused primarily by penetration and

colonization of root canal space by a wide-ranging

microbial flora (2). Continuous egress of pro-

inflammatory microbial products from an endodonti-

cally infected tooth stimulates the host to develop

periapical inflammation and bone loss (3,4), frequently

as a chronic process with little or no symptoms (5–7).

To rule out problems with adjacent teeth or other

local factors as source of any symptoms, routine pulp

sensibility testing is typically executed. Unfortunately,

these clinical tests are not always accurate (8,9). A

significant weakness of most such tests is that they only

give an assessment of the neural reaction to thermal

stimuli and no information about the state of pulpal

vasculature and blood supply (10). Both false positive

and false negative results can occur. Thermal tests may

indicate or support suspected pulpal pathosis or apical

periodontitis but they are unreliable in the presence of

pulp canal obliteration (11) immature teeth (12),

trauma (13) and multirooted teeth (14). Unless there

bs_bs_banner

Endodontic Topics 2012, 26, 57–75

All rights reserved

2013 © John Wiley & Sons A/S

ENDODONTIC TOPICS

1601-1538

57

n

Strategies

§ Case reports

Strategies

n

§ Various endodontic outcomes! -! hard tissue changes, secondary soft tissue changes?

Other Possibilities?

Strategies

n CBCT and Outcomes80% of ‘‘short’’ root filling appeared as ‘‘flush’’ fillings on CBCT, ‘‘flush’’ fillings appeared as overextensions on CBCT.CBCT detected root fillings with voids in 46% of roots, almost 3 times as many as those detected by radiographs

Liang YH, Li G, Wesselink PR, Wu MK

J Endod. 2011

Best outcome:filling is 0-2 mm from the apex, and no voids

Liang YH, Li G, Shemesh H, Wesselink PR, Wu MK.

Clin Oral Investig. 2012

Apical fenestration / pain with extrusion of canal filling material into the soft tissues and a periosteal reaction were detected by CBCT.

Pasqualini D, Scotti N, Ambrogio P, Alovisi M, Berutti E.

Int Endod J. 2012

CBCT might change outcome predictors for endodontic treatment.

Wu MK, Shemesh H, Wesselink PR, Patel S

J Endod. 2012

n

Strategies

Decision Makingn

Kvist 2004

§ Continuous disease scale

n

Strategies

Pre-opradiograph

Casehistory

Finalradiograph

Retreatment (UN, 05)n

Recallradiograph

- 20 yr old fill- asymptomatic- restoration adequate- very motivated patient

Strategies

Key Evidence§ Clinical! - retrospective data from many groups - cross-sectional data, overall poorer outcomes

§ Assessment tools! - clinical impression, p.a. radiographs, CBCT

§ Data from large cohorts (insurance, PBRN)! - retention of root canal treated teeth is very high - reasons other than primary endodontic failure often associated with extractions

n Introduction

n Strategies

n Discussion

Strategies

n Introduction

n Strategies

n Discussion

n

Strategies

Patient’s Age[years]

Inte

grity

6 10 20 30 40 50

Restorations

A Tooth’s “Career”

RCTPA

lesion

Endodontics

Strategies

Non-Instrumentation Technique§ NaOCl at low atmospheric pressure! -!complicated tubing system for delivery! - in vitro successful, clinically problematic

Lussi group

n Introduction

n Strategies

n Discussion

Strategies

• Targets  pulp  ,ssue  with  controlled,  varied  energy  waves

• Simultaneous  cleaning  of  pulp  chamber  and  root  canals  

• No  need  for  individual  sequen,al  canal  treatment

Unique  Cleaning  Technology

A"er

 Before

Ultrasonic:  Single  frequency

Laser:  Single  frequency

Files:  200+  years  old

Sound  Science.

CONFIDENTIAL

Strategies

?

?

?

Redefining  Clean  Pulp  ChambersGreatly  enhanced  cleaning

Result:   Cases  that  previously  required  extensive  4me/

irriga4on/instrumenta4on  now  can  be  cleaned  quickly  and  completely  regardless  of  chamber/canal  morphology

CONFIDENTIAL

A Comparative Stu

dy of Biofilm Remova

l with Hand, Ro

tary

Nickel-Titanium,

and Self-Adjusti

ng File Instrumenta

tion

Using aNovel In

Vitro BiofilmModel

James Lin,DDS, M

Sc, YaShen, D

DS, PhD, and

MarkusHaapa

salo, DDS, Ph

D

Abstract

Introduction: T

his study sough

t to present a sta

ndard-

ized biofilmmodel in

extracted teeth with an artificial

apical groove to quantify

the efficacyof hand

, rotary

nickel-titanium,

and self-adjustin

g file (SAF) inst

rumen-

tation in biofilm bacteriaremoval

. Methods:Thirty-si

x

extracted single-ro

oted teeth with oblongcanals w

ere

selected. Each tooth was split longitud

inally, and

a 0.2-mm-wide gr

oove was placed

in the apical 2 to 5

mm of the canal. Af

ter growing mixed bacteria

biofilm

inside the canal

under ananaerob

ic condition, the

split

halves were reas

sembledin a cust

om block, creating a

n

apical vapor loc

k. Teethwere randoml

y divided into 3

treatment group

s (n = 10 per group) using

the K-file,

ProFile(Dentsp

ly Tulsa DentalProducts

, Tulsa,OK),

and theSAF (Re

Dent-Nova, Ra’a

nana, Israel). Irr

igation

consisted of 10

mL 3%NaOCl a

nd 4 mL17% EDTA. S

ix

teeth receivedno treatme

nt. Areas inside

and outside

the groovewere examine

d using a scanningelectron

microscope. Resu

lts: Thescanning

electronmicrosco

pe

showeda consis

tently thick layer

of biofilmgrown in

the

canals of the control

group after 4weeks.

Within the

groove,a smaller

area remained occupied

by bacteria

after the use of the SAF compare

d with the ProFile

and the K-file (3.25%, 19.25%, and 26.98%

, respec-

tively; P < .05). For all groups,significa

ntly more

bacteriawere removed

outsidethe groove

than inside

(P < .05). Nostatistica

l differences we

re foundoutside

the groove(P > .05). Co

nclusions: Alth

ough all tech-

niquesequally

removedbacteria

outsidethe groove,

the SAF reduced significa

ntly more bacteria

within the

apical groove. N

o technique was able to remove

all

bacteria. This biofilm

model represen

ts a potentially

useful tool for th

e futurestudy of

root canal disinf

ection.

(J Endod2013;39

:658–663)

Key Words

Biofilm,endodon

tic instrument, irrig

ation, nickel-tita

-

nium, ProFile, se

lf-adjusting file

Colonizing microo

rganismssuch as t

hose found in the

infectedroot can

al spaceare

present either as f

ree-floating (plan

ktonic) single cel

ls or attached to e

ach other or

to the root canal

walls to form (sessile)

biofilms. Althoug

h planktonic mic

roorganisms

can be eliminated

more readily by a

variety of differen

t methods, the rem

oval of sessile

biofilm bacteriafrom the root

canal remains a

major challenge (

1, 2). Abiofilm is

a community of

microorganisms

embedded in a matrix

of extracellular p

olymeric

substance and attached

to a solid surface.It has b

een acceptedthat with

in this

community the biofilm

bacteriaexpress

differentphenotyp

es, oftenwith different

characteristics, t

han do the samebacteria

in their planktonic

state. Notable am

ong

these differences

is the increased

resistance to anti

microbial agents

that canbe 100-

to 1000-fold grea

ter for aspecies i

n a mature biofilm

relative to that sam

e speciesgrown

planktonically (3

). Microbial inva

sion of the root

canal system can even

tually lead to

pulpal necrosis a

nd apical periodo

ntitis. Because the

bacteriain the ne

crotic root canal

grow mostly insessile fo

rms, thesuccess

of endodontic tre

atment will depen

d on the

effectiveeliminati

on of such biofil

ms (1).

Currently, the era

dicationof a micr

obial infection is a

ccomplished main

ly through

mechanical instru

mentation and ch

emical irrigation.

Althoughmechani

cal preparation

of the infected roo

t canal has been s

hown tobe most

effectivein reduc

ing the number o

f

bacteria,it alone

is unreliable in

achieving adequ

ate disinfection (4, 5).

Irrigation

allows for cleaningbeyond

what might be

achievable through

instrumentation

becauseit enhan

ces further bacte

rial elimination,

facilitates necrot

ic tissueremoval,

and prevents the

packingof infect

ed debris apicall

y (2). Nonethele

ss, the anatomic

complexities of th

e root canal syste

m presentphysical

constraints that po

se a serious

challenge to adequate

root canal disinf

ection using currentlyavailable

techniques

such that residua

l bacteria are oft

en foundin areas

such asfins, isth

muses, ramifica-

tions, deltas, acc

essory and lateral c

anals, and dentinal

tubules(6, 7).

Recently,

a new instrumentation a

nd irrigation devi

ce, the self-adjus

ting file(SAF) sy

stem, was

introduced by ReDe

nt-Nova(Ra’anan

a, Israel) (8). Dif

ferent from the tradition

al

nickel-titanium (NiTi) ro

tary files, the SAF

system uses a hollow reciproc

ating instru-

ment that allows

for simultaneous

irrigationthrougho

ut the mechanica

l preparation.

When inserted in

to the root canal,

the manufacture

r claimsthat the

SAF is capable of

adaptingitself to t

he canalshape 3-

dimensionally (9)

. The instrument

is used ina trans-

line (in-and-out)

motion,and the abra

sive surface of th

e latticethreads

promotes

a uniformremoval

of dentin(8). Siqu

eira et al (10) fo

und thatSAF prep

aration and

continuous irriga

tion of long oval c

anals were more

effectivethan rota

ry NiTi instru-

mentation and sy

ringe/needle irrig

ation inreducing

intracanal Enter

ococcusfaecalis

counts.

From the Division of E

ndodontics, Dep

artmentof Oral B

iological and M

edical Sciences, F

aculty of Dentis

try, TheUniversi

ty of British Colu

mbia, Vancouver

, British

Columbia, Cana

da.

Addressrequests

for reprints to D

r Markus Haapasalo

, Division of End

odontics, Depart

ment ofOral Bio

logical and Medical Sc

iences, UBC Faculty o

f Dentistry, 2199

WesbrookMall, Vanc

ouver, BC, Cana

da V6T1Z3. E-m

ail address: mark

ush@dentistry.ubc.ca

0099-2399/$ - s

ee frontmatter

Copyright ª 2013 Am

erican Associatio

n of Endodontist

s.

http://dx.doi.org/

10.1016/j.joen.2

012.11.012

Basic Research—Technolo

gy

658 Lin et al.

JOE —Volume

39, Number 5, M

ay 2013

n

Strategies

§ The model! -! teeth were split and grooves prepared in apical third - biofilm grown in canal - halves observed with SEM

§ The outcome! -!out of hand instrumentation ProFile and SAF, none was removing all biofilms, SAF was most effective

n

Strategies

Apical Size & Disinfection§ The threshold! -!no sterile root canals but low numbers (10-100)

CFU

[log

10]/

mL

MAF [ISO #]

10 20 30 40 50 60 70

23456789

1

n Introduction

n Strategies

n Discussion

n

Strategies

- Invasive +

Decontamination-Disinfectionn Introduction

n Strategies

n Discussion

Strategies

Issue: Longevity§ Patient demographics! -!anecdotally, many patients are >75 years old! -!cost of treatment is high! -!alternatives are available

§ Healing or survival?! -!which goal should we consider! -!what determines survival of treated teeth

§ Pathways for improvement! -! less invasive treatment strategy! -!specific issues when this is adopted

n Introduction

n Strategies

n Discussion

Jan 1997 May 2000

n

Strategies

Oct 2000

Strategies

Conclusion§ Evidence-based endodontics! - an effort to practice based on knowledge - understand that for many procedures there is little....

§ Willingness to continue to self-educate! - new materials and devices - cognitive and hand skills

§ Treatment potential! -! conventional root canal therapy, retreatment, surgery - regenerative endodontics, traumatology, implants....

n Introduction

n Strategies

n Discussion

Strategies

§ “More of the same” - refined instruments that are more efficient and safer - easier market penetration but limited innovation

§ Minimal invasive - limited enlargement and retained structural integrity - specific set of challenges

§ Not at all - specific non-instrumental techniques - alternatively, vital pulp therapy or regeneration

Preparation Possibilitiesn Introduction

n Directions

n Discussion

n

Strategies

How Are We Doing Now?

§ 2006! -! irreversible pulpitis! -!NiTi rotary! -! vertical condensation

§ 1987! -! necrosis, s. p. p.

! -!Giromatic! -! lateral compaction!

23yr recall

n Introduction

n Directions

n Discussion

Strategies

Brief Summaries§ Key 1: Access! - as small as practical

n Introduction

n Strategies

n Discussion

§ Key 2: Cleaning and Shaping! - many strategies, some hints to best practices

§ Key 4: Follow-up care! - the current tools are poor and decisions empirical

§ Key 3: Obturation! - no best technique established, no overextension

Strategies

Clinical Studies

§ Added benefit may be too small to measure! -! clinical (prospective) studies indicate high healing rates ! ! with a wide range and little change in the last 60 years

§ One variable among several others ! -! outcome analyses in endodontics are multifactorial! -! other variables can be overriding

Marending 2005

§ Some surrogate outcome variables! -! disinfection capability! -! presence and incidence of preparation errors

Schäfer 2004

McGurkin 2004, Card 2002

n Introduction

n Strategies

n Discussion

Strategies

Conclusions§ Long-range: two pillars - vital pulp therapy - minimal invasive conventional endodontics

§ Cognitive framework - establish best practices, currently insufficient evidence - socioeconomics and access to care

§ Transition period - gradual R & D for both - special cases: define indications and techniques

n Introduction

n Directions

n Discussion

Strategies

Thank you Very Much!n Introduction

n Strategies

n Discussion