Determining the Working Length - Apex NRG Powerpoint ( LARGE ...
dr VLADIMIR IVANOVIC , DDS, MSc, PhD, SDS Professor in Restorative Odontology & Endodontics, University of Belgrade, Republic of Serbia
DETERMINING THE WORKING L E N G T H Mirjana Vujašković Katarina Beljić- Ivanović Ivana Bošnjak Jugoslav Ilić L E N G T H
SEEKING WHERE, WHEN, WHY AND HOW TO LOCATE THE APICAL TERMINUS OF THE ROOT CANAL PREPARATION Joshua Moshonov Julian Webber Paul Dummer William Saunders
<ul><li>Apical limit of root canal instrumentation and obturation (1 & 2) </li></ul><ul><li>D Ricucci & K Langeland, 1998, IEJ </li></ul><ul><li>Apical terminus location of root canal treatment procedures. </li></ul><ul><li> M-K Wu, P Wesselink & RE Walton, 2000, 4O’s & Endo </li></ul><ul><li>Considerations in working length determination. </li></ul><ul><li> LRG Fava & JF Siqueira, 2000, Endodontic Practice </li></ul><ul><li>The fundamental operating priciples of ERCLMDs. </li></ul><ul><li>MH Nekoofar, SJ Hayes & PMH Dummer, 2006, IEJ </li></ul><ul><li>Determination of true working length. </li></ul><ul><li>R Mounce, 2007, EndoPractice </li></ul>Articles that have been “guiding light” in creating my own standpoints, and directing “pathways” of this lecture by their philosopohy and conception
<ul><li>Predetermined “normal” tooth length </li></ul><ul><li>Patient response to pain </li></ul><ul><li>Tactile sensation of the therapist </li></ul><ul><li>Paper point technique </li></ul><ul><li>Radiographic method </li></ul><ul><li>Electronic locators </li></ul>METHODS OF DETERMINING THE WORKING LENGTH
Patient response to pain - apical sensitivity <ul><li>Many false information, misleadings, </li></ul><ul><li>& limitations; extremely subjective = </li></ul><ul><li>=> unreliable </li></ul><ul><li>- remnants of vital pulp tissue </li></ul><ul><li>- pressure of the instrument tip via debris </li></ul><ul><li>- destruction of PA tissues – no sensation </li></ul><ul><li>- individual sensitivity – pain threshold </li></ul><ul><li>- local anaesthesia </li></ul><ul><li>- poor / no evidence in literature </li></ul><ul><li>Is it still in use, or gone to dental history ? </li></ul>
Tactile sensation of the operator <ul><li>Very subjective, with limitations, often misleading </li></ul><ul><li>=> unreliable </li></ul><ul><li>- morphological irregularities: narrowing, </li></ul><ul><li>calcification, </li></ul><ul><li>multiple constrictions </li></ul><ul><li>- tooth type & age </li></ul><ul><li>- pathological resorption & wide AF </li></ul><ul><li>- a few evidence in literature </li></ul><ul><li>Still advocated as very useful in hands of an </li></ul><ul><li>experienced practitioner to feel and identify AC !? </li></ul>
Tactile sensation Precise in only 19%; with +/- 0.5 mm tolerance accuracy in 42%. Significant under and overestimations up to 4.5 mm before and beyond RP !!! M.V. & M.P. : 1984 Literature data : to locate apical constriction accuracy varies: 3 0% - 44% - 60% with wide and random distribution of measured values Preflaring enhances locating of the AC, and increases accuracy: 32% up to 75% Referent point from R ö apex : 0.5mm in <25 yrs; 1.0 mm in > 25 yrs “ Belgrade clinical study”
Paper point technique <ul><li>Claimed as the most precise method to determine: </li></ul><ul><li>i) working length to the end of the canal, and </li></ul><ul><li>ii) min. apic. for.diam. (MAFD) in 3D </li></ul><ul><li>Allows practitoner to “see” the </li></ul><ul><li>cavosurface of the canal </li></ul><ul><li>with the precison of 0.25 mm; </li></ul><ul><li>- apical patency technique - </li></ul><ul><li>Wet (blood) / dry interface coincides with the location of the CS </li></ul><ul><li>Enables to customise gutta-percha master cone 3D </li></ul><ul><li>upon the information from the PP </li></ul>
Paper point technique By courtesy of J. Webber DB Rosenberg
Paper point technique <ul><li>Even claimed as the most precise method in determining WL there is neither scientific nor clinical evidence in literature on its superiority </li></ul><ul><li>In spite of being advocated by many endodontic experts, </li></ul><ul><li>PP technique lacks in respect to morphological details and </li></ul><ul><li>pathological state within the root canal and in periapical tissues </li></ul><ul><li>“ The use of PP as a simple device in sophisticated ways”- ( Rosenberg ) </li></ul><ul><li> could be advised as an accessory / assisting mean to establish and </li></ul><ul><li>confirm final WL, since it is non-aggressive, “soft” method, and </li></ul><ul><li>therefore cannot injure tissues or disturb wound healing </li></ul>
Radiographic method REVEALS, ASSISTS, BUT OFTEN GIVES AN “ILLUSORY TRUTH” PREOPERATIVE – DIAGNOSTIC RADIOGRAPH IS MANDATORY !
Radiographic apex and anatomical apex do not (always) coincide ! . Apical foramen cannot be (always) visualised on a radiograph ! R ö A Important details are not always detectable on the clinical radiograph
M.V. & M.P.:1988 Referent point from R ö apex : 0.5mm in <25 yrs; 1.0 mm in > 25 yrs Precise in 51%; tolerance +/- 0.5 mm -> accurate in 68%; tolerance extended +/-1 mm accurate in 88%; Under and overestimations not over 2 mm ! Literature data: Accuracy widely ranges from 50% - 77% - up to 97% Radiographic method “ Belgrade clinical study”
Measuring file is longer than it appears radiographically ! When instrument is short of the R ö apex surprisingly is beyond AF in 43% ! If AC is 0.5 mm before apex then 66% of all measurements are “beyond” ! I.B.
NO DOUBT – BEYOND but could be solved successfully 22
When short of the R ö apex it is actually closer to the AF ! “ ... r adiographic working length ending 0 - 2 mm short of the radiographic apex provides, more often than expected , a basis for unintentional over instrumentation ”
NO DOUBT – SHORT But could be solved successfully 12 Radiographs are indispensable for calculating , but not for determining WL !
K..B-I. Radiovisiography - RVG Digital radiography Assisted by RVG, only ! 37 S. Andjelkovic
Digital radiography - RVG <ul><li>Quantifies distances </li></ul><ul><li>Image could be varied by software programme </li></ul><ul><li>Fine file tip – low contrast structures – </li></ul><ul><li>affect visualisation and measuring precision </li></ul><ul><li>Better results with #15 or #20 files </li></ul><ul><li>Image quality bellow conventional R ö </li></ul><ul><li>Inferior to ELs – longer measurements </li></ul>S. Andjelkovic
Radiographic method relies still on many assumptions, arbitrary calculations, averages, speculations and “illusory images”, that add to the confusion rather than giving solution ! Adequate radiographs, knowledge of anatomy, and tactile sense, and not “apex locators” - - will help to determine apical constriction ! “ GIVE LOCATORS A CHANCE”
<ul><li>Resistance-based devices I </li></ul><ul><li>Low frequency oscillation devices II </li></ul><ul><li>High frequency (capacitance-based) devices II </li></ul><ul><li>Capacitance & reistance device (access. look-up table) IV </li></ul><ul><li>Voltage gradient-based devices ?? </li></ul><ul><li>Two frequences (impedance diference)-based devices III </li></ul><ul><li>Two frequences (impedance ratio-quotient) devices III </li></ul><ul><li>Multi frequency-based devices III </li></ul>ELECTRONIC FORAMEN LOCATORS ELECTRONIC APEX LOCATORS “ The use of “generation X” to describe and clasify these devices is unhelpful, unscientific and perhaps best suited to marketing issues” These are the very same devices, but just under different brand-name, showing how market functions and manufacturers „cooperate “ ERCLMD, . . . - ”lot of words descriptive” – no length CLASSIFICATION of EFLs
<ul><li>Embedding media - simulate clinical conditions (peridontal ligament) </li></ul><ul><li>Electrical properties of intracanal solution: </li></ul><ul><li>extreme conductivity and ion concentration (type of EFL) </li></ul><ul><li>File size in respect to the diameter of the AC and AF: </li></ul><ul><li>wise to use smooth canal instruments - less damage to fine structures </li></ul>In vitro (ex vivo) measuring the accuracy of EFLs <ul><li>Type of EFL: the newer model the better and more consistent results </li></ul>- variables influencing and affecting results -
Variables influencing and affecting results of ex vivo measuring the accuracy of EFLs: <ul><li>Preflaring: improves determination of apical diameter and </li></ul><ul><li>first file that binds, stabilises readings, increases precision </li></ul><ul><li>Range of tolerance: from +/- 0.1 mm, mostly +/- 0.5 mm, up to 2 mm; </li></ul><ul><li>the wider the range the higher the percent of EFL accuracy ! </li></ul>- Apical land mark chosen to determine “real/actual length” (RA / AL) Most are valuable / useful for practice; majority was conducted in single rooted / canal teeth and suffer of too many variables !
Differences bellow 0.5 mm are clinically not significant due to our manual abilities ! Are differences between real values and on EFL’s significant ? 303 Figures/marks on a display of EFL’s scales do not represent values in mm ! 300
What about occasionally unstable readings - bouncing indicating marks ? In clinical use to wait for 3-5 seconds to achieve stable reading !
Tolerate small differences which are not noticeable clinically ? Bellow 0.5 mm ! 300 m 202 m Differences clinically acceptable !!
How strong readings on a display correspond to the real values on a high-tech measuring instrument ? Precision and high resolution ! Extremely small distorsions from the real measures! 0.012– 0.038 mm 0.022– 0.065 mm Far away of any concern!
How exact readings on a display correspond to the real values on the high-tech measuring instrument ? What do they indicate ? What is the clinical relevance ? < 0.06 mm 0.35-0.19= 0.16mm 1.45 -1.25= 0.20mm Differences far bellow clinically tolerable +/- 0.5 mm !! 0.001 mm Indicate high level of resolution ! The closer to the apex, the more precise the readings are & higher is the resolution!!
Can we follow with confidence what display indicates upon manufacturer’s instructions ? Four yellow segments indicate region between AF and AC (0.5 – 1.0 mm) ! EFLs scales do not represent values in mm !
Three green segments indicate region of the apical constricion ( ~ 1.0 mm) Follow what display indicates and manufacturers instructions, but ”filtrate” and reconsider unusual and “strange” readings !!
Until spreader reached plastic barrier Tip of the finger spreader to the flat plastic surface placed firmly at the plane of the anatomical foramen ! Do different foramen locators display the same values for the same distance in the same root canal ?
Do different foramen locators display the same values for the same distance in the same root canal ? No, they do not !
0 - 508 - 701 0 - 354 - 705 0 - 305 – 380 0 - 367 - 674 0 - 143 - 312 Distance between warning “beyond foramen” => reading foramen => ” switch” to one mark/segment “short of foramen ” 193 (300) 351 (340) 75 (48) 307 (350) 169 (202) 0.0 0.1 - 0.0 Apex 0.25 Apex AP EX 0.0 0.1 ( m ) Apex Pointer + Dentaport ZX Apex NRG XFR Propex I Raypex 5 range in m resolution / “subtlety” from – to Electronic foramen locator
Different foramen locators show different values with different level of resolution for the same distance in the same root canal ! All deviations are far bellow range of clinically acceptable tolerance of +/- 0.5 mm, therefore they do not significantly influence the accuracy of EFLs in locating apical foramen !!
more realistic / relevant / reliable information useful for practitioners Factors that affect readings and/or accuracy of EFLs: - Vital – necrotic cases - Preflaring - Canal content: infl. pulp tissue, puss, detritus; empty/dry - Conductive properties and ions concentration of irrigating solution - Diameter of the minor and major foramen (pathol. – instrum.) - Size of the measuring file - Tooth type: front - posterior / single – multi canal - Type of material the measuring file is made of In vivo studies - on teeeth to be extracted:
More consistent, straight forward, faster and precise readings when: - coronal /middle/ portion preflared - pulp tissue extirpated – debris removed - moderately conductive irrigating solution: 2% NaOCl, CHX, EDTA - foramen is not enlarged by periapical pathosis / instrumentation - size of the file coincides with lumen of the apical portion No affect on readings and accuracy: - Tooth type: front - posterior / single – multi rooted (canal) - Type of material the measuring file is made of
Contradictory & controversial results / statements on: - vital vs. necrotic - moist vs. dry: type of EFL - high conductive vs. low conductive irrigant: type of EFL Adverse effect on readings: - extremes in conductive properties of a solution in the canal: saline vs. destilled water - PA lesions associated with destruction of PL, AF, AC and bone - wide open AF in immature teeth
Variables influencing clinical results of EFLs accuracy : (varies from 15% up to 100%) <ul><li>mark on a display chosen to be “apical terminus” for EWL: </li></ul><ul><li>“ 00” / “Apex” vs. “-0.5”/”AC; -1.0; yellow or green segment – </li></ul><ul><li>or each operator will chose the mark that he wants to call his </li></ul><ul><li>OWN APICAL TERMINUS </li></ul>- range of tolerance/targeted interval: +/- 0.5; +/- 1.0; +/- 1.5 mm; higher tolerance -> higher % of accuracy - anatomical land mark chosen to measure distance from the file tip: AC & CDJ vs. AF & AnAp - method to establish precision of the locator: micrsocsopy measurement - software programmes for extracted teeth samples vs. comparison with clinical radiograph Manufacturers should define clearly which lendmark their product locates !
M P , M V & V I : in early 80’s of the last century Domestic h and- made device “Diapex” “ Odontometer” – Goof, DK “ Belgrade clinical studies on EFLs”
M.P & M.V. : 1988 - 1990 Precise in 77% with +/- 0.5 mm tolerance. Overestimations of + 0.5 mm in only 4% ! Referent point from R ö apex : 0.5mm in <25 yrs; 1.0 mm in > 25 yrs “ Belgrade clinical studies on EFLs” Precise in 67% of vital teeth, and in 76% of teeth with necrotic pulp, with +/- 0.5 mm range of tolerance. Mostly underestimations of -1.0 mm ! M.V. & D. I.: 1996 “ Odontometer” Alternating current impedance measuring device- in dry canal
Accuracy of EFLs checked in clinical situation by R ö ? <ul><li>Traditionally EFLs accuracy has been corroborated by R ö , but any correction of the file position according to R ö projections would invariably lead to overextension ! </li></ul><ul><li>Comparison of precision of EFLs with R ö is not accurate because R ö is unreliable method in determining AC & AF ! </li></ul>
<ul><li>“ Propex I”: Dentsply/MAILLEFER (D. Nobs & S. Fultinavicius) </li></ul><ul><li>“ Raypex 5”: VDW ( L. Satanovskij ) </li></ul><ul><li>“ Apex NRG XFR”: Medic NRG ( M. Zach, A. Beker, E. Friedman) </li></ul><ul><li>“ ApexPointer+”: MicroMega (C. Dort & A. Stephany) </li></ul><ul><li>“ Dentaport ZX”: J. Morita (J. Bohnes) </li></ul>“ Belgrade in vivo studies ” In vivo - in molars and multirooted premolars to be extracted: 30 canals per locator !
Referent point was tangential line to the AF Mark on a display indicated AF: “ 0.0”, “Apex”, “red segment”
0.148 (0.079) 0.187 (0.142) Ø 3 ; 9 ; + 0.226 (0.102) 0.169 (0.149) 0.165 (0.222) 0.189 (0.168) 2 ; Mean distance from the file tip to the AF - in vivo determined 1 ; + 0.129 + 0.076 + 0.131 + 0.119 + 0.208 + 0.075 Majority showed high SD – dispersion of values All EFLs 100% precise within 0.2 mm range of tolerance; Seldom overestimations with small values - clinically acceptable NRG XFR small SD - consistent measuring; no beyond AF Apex Pointer + Raypex 5 Propex I Dentaport ZX Apex NRG XFR Beyond AF Mean (+/- SD) Electronic foramen locator
“ When apical foramen is located the position of the apical constriction (if exists) can be estimated ”
Always have preoperative radiograph and stay within confines of the root canal ! Determining WL upon preop R ö and EFL, only ! K..B-I.
WL upon preop RVG, and EFL, only !! Extreme narrow canals: R ö and EFL TRUST in EFLs , BUT NOT BLINDLY !! K..B-I.
COMBINING AND COMPARING SEVERAL METHODS GIVE MORE CONFIDENCE, ACCURACY AND SUCCESS THAN USING ONLY ONE OR EVEN NONE ! Crown-down tapered preparation; WL - 0.25 mm before AF: tactile sensation, EFL, R ö and PP ; rotary NiTi instrumentation & cold lateral
PREDICTABLE, RELIABLE AND SUCCESSFUL ENDODONTICS 46 36 Let’s produce perls of endodontic treatment giving always our best twin-like
Regards from Belgrade !!! MANY THANKS FOR YOUR ATTENTION 1997 th