Transcript DIREKTNI I INDIREKTNI KOMPOZITNI ISPUNI

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