View - Sandra Kalil Bussadori

Original Paper
Caries Res 2008;42:79–87
DOI: 10.1159/000113160
Received: June 4, 2007
Accepted: October 29, 2007
Published online: January 15, 2008
Reproducibility and Accuracy of the
ICDAS-II for Detection of Occlusal Caries
in vitro
a
A. Jablonski-Momeni V. Stachniss b D.N. Ricketts c M. Heinzel-Gutenbrunner a
K. Pieper a
Departments of a Paediatric and Community Dentistry and b Operative Dentistry, Philipps University
of Marburg, Marburg , Germany; c Section of Operative Dentistry, Fixed Prosthodontics and Endodontology,
Dundee Dental School, University of Dundee, Dundee , UK
Key Words
Histology International Caries Detection and Assessment
System Microscopy Occlusal caries Visual inspection
detection of occlusal caries at varying stages of the disease
process which are comparable to previously reported data
using similar visual classification systems.
Copyright © 2008 S. Karger AG, Basel
Abstract
Aim: The aim of this study was to assess inter- and intraexaminer
reproducibility and accuracy in the detection and
assessment of occlusal caries in extracted human teeth using
a newly developed visual method for caries diagnosis
(International Caries Detection and Assessment System,
ICDAS-II). Serial sectioning and microscopy were used as the
‘gold standard’. Methods: The occlusal surfaces of 100 teeth
were examined by 4 dentists using the ICDAS-II graded
scores 0–6. Thereafter the teeth were serially sectioned and
assessed for depth of the lesion with two histological classification
systems. Results: The weighted kappa values for
inter- and intra-examiner reproducibility for the ICDAS-II
examination were 0.62–0.83. There was a moderate relationship
between the visual and both histological examinations
(r s = 0.43–0.72). At the D1 diagnostic threshold (enamel and
dentine lesions) specificity was 0.74–0.91 and sensitivity was
0.59–0.73. At the D3 diagnostic threshold (dentine lesions)
specificity was 0.82–0.94 and sensitivity was 0.48–0.83 for
the 4 examiners. Conclusion: The ICDAS-II system has demonstrated
reproducibility and diagnostic accuracy for the
Dentists have a number of methods at their disposal
for the clinical detection of dental caries on occlusal surfaces.
Apart from purely visual and visual-tactile caries
diagnosis, these include radiography, laser or light fluorescence-based
methods and electrical impedance measurements.
Unfortunately, where occlusal caries is concerned,
a lesion which is reliably detected from a bitewing
radiograph will be advanced, having extended into the
middle third of dentine [Ricketts et al., 1995]. Whilst research
into laser fluorescence methods has resulted in the
production of a commercially available device for clinical
use, a systematic review of the literature has shown that
the majority of studies using it have been in vitro and that
false positive results (low specificity) are a problem [Bader
and Shugars, 2004]. Sheehy et al. [2001] have also
commented that visual inspection seems better suited to
epidemiological investigations than laser fluorescence,
for example. Like the laser fluorescence device, electrical
conductance methods for caries detection suffer from a
lower specificity than clinical visual methods of caries
Fax +41 61 306 12 34
E-Mail karger@karger.ch
www.karger.com
© 2008 S. Karger AG, Basel
0008–6568/08/0422–0079$24.50/0
Accessible online at:
www.karger.com/cre
Dr. Anahita Jablonski-Momeni
Department of Paediatric and Community Dentistry
Philipps University of Marburg, Georg-Voigt-Strasse 3
DE–35033 Marburg (Germany)
Tel. +49 6421 286 3215, Fax +49 6421 286 6691, E-Mail momeni@staff.uni-marburg.de

detection and further research is required before they
could be used in caries clinical trials [Longbottom and
Huysmans, 2004].
In epidemiological examinations, caries has usually
been diagnosed according to the WHO standard, that is,
lesions are recorded at the cavitation level. As defined by
the WHO [1997], caries requires operative treatment (D 3
level) when exposed dentine is visible or undermined
enamel with softened margins can be felt. Such lesions
are likely to be extensive, extending well into dentine,
and rapidly progressive. Therefore, subtler indices are required
which can also register lesions at an earlier noncavitated
stage. This is the only way to establish a valid
basis for caries management aimed at remineralisation of
early enamel and dentine lesions. A system for clinical
caries diagnosis would be ideal if on the one hand it could
detect caries at an early stage and on the other provide
practitioners with a basis for suitable therapies.
The International Caries Detection and Assessment
System (ICDAS) for clinical caries diagnosis was developed
to provide clinicians, epidemiologists and researchers
with an evidence-based system which would allow
standardised data collection in different settings and better
comparison between studies. The aim is to provide
better understanding of caries and its management within
the population and at an individual level [Pitts, 2004].
ICDAS was developed on the basis of insights gained
from a systematic review of the literature on clinical caries
detection systems [Ismail, 2004] and other sources
[Ekstrand et al., 1997, 2001, 2005; Fyffe et al., 2000a;
Chesters et al., 2002; Ricketts et al., 2002]. Use of the
ICDAS was intended to make subsequent studies more
useful for comparison, reviews or meta-analyses and thus
fulfil the requirements of evidence-based dentistry [Richards,
2005].
The aim of this in vitro study was to validate the
ICDAS-II system for caries detection in pits and fissures
using two histological classification systems used in previous
studies. In addition, the reproducibility of the
method was checked against a reference examiner who
was familiar with the ICDAS-II system as well as intraexaminer
reliability.
Materials and Methods
Sample Selection
One hundred unrestored molar (n = 85) and premolar teeth
(n = 15) were selected from a group of extracted teeth stored in
thymol. These were cleaned carefully with a rotating brush and
water and then stored in water.
Table 1. ICDAS-II criteria
ICDAS-II
code
Criteria
0 Sound tooth surface: no evidence of caries after prolonged
air drying (5 s)
1 First visual change in enamel: opacity or discoloration
(white or brown) is visible at the entrance to the pit or
fissure after prolonged air drying, which is not or hardly
seen on a wet surface
2 Distinct visual change in enamel: opacity or discoloration
distinctly visible at the entrance to the pit and fissure
when wet, lesion must still be visible when dry
3 Localized enamel breakdown due to caries with no visible
dentine or underlying shadow: opacity or discoloration
wider than the natural fissure/fossa when wet and
after prolonged air drying
4 Underlying dark shadow from dentine 8 localised
enamel breakdown
5 Distinct cavity with visible dentine: visual evidence of
demineralisation and dentine exposed
6 Extensive distinct cavity with visible dentine and more
than half of the surface involved
One to four easily re-located sites within the pit and fissure
system of each tooth were chosen as potential investigation sites
(total sites 181). Digital images of the occlusal surfaces were taken
with the teeth surrounded by a right-angled coordinate system,
which allowed accurate recording and identification of the investigation
sites ( fig. 1 ). Black and white copies of these, printed in
draft quality on plain paper, were used by the examiners during
this study and were only suitable for lesion location.
Training in ICDAS-II
Prior to the visual examination, the reference examiner
(D.N.J.R.) trained 3 other examiners (K.P., V.S. and A.J.-M.) in
the ICDAS-II classification system in a 2-hour session. The training
involved a 30-min lecture on the ICDAS-II system and the
importance of examining clean teeth when both wet and dry. The
details of each score were discussed and a series of images of the
occlusal surface and corresponding histological appearance were
shown to demonstrate that small and subtle changes at the entrance
to the fissure can correspond to marked histological
changes. Following this a series of approximately 20 projected,
magnified images of the occlusal surfaces of teeth with a range
of appearances were discussed and a consensus ICDAS-II score
assigned. This was followed by examination of approximately 20
extracted teeth that were not included in the main study, representing
all ICDAS-II scores. These teeth were initially examined
blind to other examiners, followed by discussion and a consensus
score given.
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ML
b
ML
ML
H
a
ML
Fig. 1. Occlusal view of a molar tooth with right-angled triangle coordinating system. The length of the embedded
coloured foil (grey in the printed version) allows accurate location of the section in the y-axis, using the
formula H = 2(a – ML). The position of the lesion along each section can then be determined by the x-axis coordinate.
Examiners
The examiners were experienced dentists with an interest in
cariology. The examiners had been qualified for 8, 20, 31 and 37
years, 2 treated both paediatric and adult patients and 2 treated
adults only. All examiners had a history of training in the assessment
of histological sections of teeth. The reference examiner had
been involved in numerous published studies using histological
assessments comparable to those used in this study.
Visual Examination
The teeth were kept moist (in water) throughout the study other
than drying for the examinations, when they were dried with
a 3-in-1 syringe as required. Each examiner examined the teeth
blind to each other according to the ICDAS-II criteria for occlusal
caries ( table 1 , http://www.icdas.org/).
After 3 weeks, 3 of the trained examiners re-examined all of
the teeth in order to determine intra-examiner reproducibility.
The reference examiner was not available to repeat the examinations,
being abroad.
Reproducibility/Accuracy of a Method for
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Caries Res 2008;42:79–87 81

Table 2. Criteria used in the histological examinations
Score
Criteria used in the Downer histological examination
[Downer, 1975]
Criteria used in the ERK histological examination
[Ekstrand et al., 1997]
0 No enamel demineralisation or a narrow surface zone of
opacity (edge phenomenon)
1 Enamel demineralisation limited to the outer 50% of the
enamel layer
2 Demineralisation involving the inner 50% of the enamel,
up to the enamel-dentine junction
No enamel demineralisation or a narrow surface zone of opacity
(edge phenomenon)
Enamel demineralisation limited to the outer 50% of the enamel
layer
Demineralisation involving between 50% of the enamel and outer
third of the dentine
3 Demineralisation involving the outer 50% of the dentine Demineralisation involving the middle third of the dentine
4 Demineralisation involving the inner 50% of the dentine Demineralisation involving the inner third of the dentine
Histological Preparation
For histological examination the roots were resected from the
teeth just apical to the cementum-enamel junction. The crowns
of the teeth were then dehydrated by serially submerging them in
increasing concentrations of alcohol solutions (40, 60, 80, 100,
100%) for 12 h in each. This progressive dehydration of the tooth
reduced damage and facilitated penetration of an alcohol/light
cure acrylic (1: 1) mix (Technovit 7200 VLC, Heraeus Kulzer, Germany)
into which the tooth was placed for 36 h. The acrylic was
then light cured for 10 h (Histolux, Exakt, Germany).
To further reduce section damage and aid mounting of the
specimen for the three-dimensional cutting technique [Stachniss,
2005], the teeth underwent a second stage of embedding in an
acrylic tube which was filled with acrylic (Technovit 7200 VLC)
to completely cover the tooth. Because visual access to the occlusal
surface and investigation sites was now impaired, an accurate
coordinating system was required to correctly assign each section
to the corresponding position within the tooth. To achieve this,
the cut root face was placed on a triangle of foil of known dimensions
(a = 9 mm), height (b = 18 mm) and angle ( = 63.5°) prior
to placement of the specimen in the acrylic tube and the second
embedding stage ( fig. 1 ). The base (a) of the triangle was aligned
with the mesial surface of the tooth and ran parallel with the occlusal
surface. The embedded tooth together with the foil triangle
were then serially sectioned in a buccolingual direction. Each embedded
section therefore contained a section of the coloured foil
in the form of a distinct line in relation to the cut root face. If the
length of the coloured line at the base of the section was ML
( fig. 1 ), the formula H = 2(a – ML) gives the height (H) or y coordinate
of the section. The correct sections could then be determined
for each investigation site, using the x coordinate recorded
on the digital photograph of the occlusal surface. Prior to histological
examination the sections were ground and polished on
waterproof silicon carbide paper (1,200, 2,400 and 4,000 grit; Hermens
or Wirz, Germany) to a specimen thickness of 200 ( 8 30)
m (checked with a digital micrometer; Müller, Germany). In total
11–15 sections were produced per crown and 1–4 sections were
available to view for each investigation site.
Histological Examination
For each investigation site the selected sections were examined
by all 4 examiners using a binocular microscope (Wild Heerbrugg
AG, Gais, Switzerland) using ! 16 magnification and reflected
light. Two different histological classification systems [Downer,
1975; Ekstrand et al., 1997] were used to record caries severity at
each investigation site and this was carried out blindly to the other
examiners ( table 2 ).
Up to 4 sections were available which could be assigned to each
investigation site. A histological score was given to each section
and the worst/deepest score was taken as the definitive score for
further analysis. For each investigation site and each histological
classification system the results from all 4 examiners were then
compared to achieve a consensus score for each site. Where 3 or
more examiners agreed on the histological score, this was taken
as consensus. Where there was greater disagreement, the sections
were reviewed by all examiners and after discussion a consensus
was reached. Caries extent was based upon colour and structural
changes in enamel and dentine, with emphasis being placed on
differentiating carious changes from protective changes of the
pulp-dentine complex, such as tubular sclerosis and reactionary
dentine formation.
Data Management and Statistical Evaluation
Both the ICDAS-II and histology scores were recorded on special
sheets and later transferred to an Excel table. Multiple investigation
sites on a single tooth do not represent statistically independent
data. To ensure that statistical analysis was based on independent
data, one site was randomly chosen (SPSS 14.0) for
each tooth with more than one investigation site, and used as the
score for that tooth.
For the ICDAS-II scores, interexaminer reproducibility was
calculated for all pairs of examiners and intra-examiner reproducibility
was calculated for the trained examiners using weighted
Cohen’s kappa (using linear weights).
For each examiner, the relationship between the visual scoring
system and both of the histological scoring systems (Downer and
ERK) was assessed using the Spearman rank correlation. The
consensus Downer histology was used to calculate sensitivity and
specificity at the D1 and D3 diagnostic threshold. At the D1 diag-
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nostic threshold all histological scores 1–4 were classed as caries
and each ICDAS-II cut-off was used to calculate sensitivity and
specificity for each examiner. Similarly for the D3 diagnostic
threshold histological scores 3 and 4 were classed as caries only
and sensitivity and specificity calculated at each ICDAS-II cutoff.
The ERK histology, using the classification 2–3 as a histological
threshold, was also used to calculate sensitivity and specificity
for each ICDAS-II cut-off. Using these sensitivity and specificity
values ROC analyses were carried out at the D1, D3 and ERK
2–3 thresholds for each examiner.
Table 3. Inter- and intra-examiner reproducibilities for visual
ICDAS-II examinations
Weighted kappa
examiner 1 examiner 2 examiner 3 examiner 4
Examiner 1 0.82 0.74 0.77
Examiner 2 0.78 a 0.70 0.74
Examiner 3 0.74 a 0.62
Examiner 4
0.83 a
a
Intra-examiner data in italics.
R e s u l t s
Initially, 100 teeth and up to 4 sections per independent
investigation site were planned for investigation,
but, owing to section damage on some teeth and to some
not being scored by all examiners, only 93 investigation
sites and 201 corresponding sections were available for
analysis (14 investigations sites had 1 section, 54 had 2
sections, 21 had 3 sections and 4 had 4 sections). The
number of sections per investigation site was dictated by
the size and spread of the lesion.
Three or more examiners agreed on the histological
assessment in 89% of investigation sites when using the
Downer classification and 84% of investigation sites when
using the ERK classification. The interexaminer weighted
kappa values were 0.66–0.75 for the Downer classification
and 0.60–0.74 for the ERK classification. Where disagreement
occurred, a consensus decision was made following
discussion and this was used in subsequent
analyses.
Table 3 shows the intra- and interexaminer reproducibilities
(kappa values) for the visual ICDAS-II examinations.
Table 4 shows the distribution of ICDAS-II data crosstabulated
with both the Downer and ERK histological
scores (consensus) for the independent investigation sites
included in this study for the reference examiner. Table 5
Table 4. Cross tables showing the relationship between the
ICDAS-II scores for examiner 1 and the consensus decision for
Downer and ERK histological classification systems for the independent
data
ICDAS-II
0 1 2 3 4 5 6
Downer histological score
0 15 7 0 0 0 0 0 22
1 4 4 4 1 0 0 0 13
2 2 4 6 1 0 1 1 15
3 0 5 5 14 6 6 0 36
4 0 0 0 0 2 4 1 7
Total 21 20 15 16 8 11 2 93
ERK histological score
0 15 7 0 0 0 0 0 22
1 4 4 4 1 0 0 0 13
2 2 5 10 9 2 2 1 31
3 0 4 1 6 4 6 0 21
4 0 0 0 0 2 3 1 6
Total 21 20 15 16 8 11 2 93
Table 5. Spearman’s correlation coefficients: visual versus histological scores
Spearman’s correlation coefficient
examiner 1 examiner 2 examiner 3 examiner 4 all examiners
Visual versus Downer histological scores 0.60 0.72 0.59 0.48 0.58
Visual versus ERK histological scores 0.58 0.68 0.54 0.43 0.54
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Table 6. Area under the ROC curve, optimum sensitivity and specificity and corresponding ICDAS-II threshold used, for each examiner
at each diagnostic threshold (D1, D3 and ERK 2–3)
D1 diagnostic threshold
AUC (SE) CI opt.
sens.
D3 diagnostic threshold
opt.
spec.
ICDAS
cut-off
AUC (SE) CI opt.
sens.
opt.
spec.
ICDAS
cut-off
Examiner 1 0.85 (0.05) 0.75–0.94 0.71 0.91 1–2 0.88 (0.04) 0.81–0.96 0.79 0.90 2–3
Examiner 2 0.86 (0.05) 0.77–0.94 0.73 0.83 1–2 0.87 (0.04) 0.80–0.95 0.69 0.90 2–3
Examiner 3 0.73 (0.06) 0.62–0.84 0.59 0.78 1–2 0.87 (0.04) 0.80–0.94 0.48 0.94 2–3
Examiner 4 0.80 (0.05) 0.70–0.90 0.73 0.74 1–2 0.88 (0.04) 0.80–0.95 0.83 0.82 2–3
AUC = Area under the curve; SE = standard error; CI = 95% confidence interval; opt. sens. = optimum sensitivity; opt. spec. = optimum
specificity.
shows the Spearman’s correlation coefficient for ICDAS-
II visual examination for each examiner, for both Downer
and ERK histological scores. It is generally accepted
that a correlation coefficient of 0.7 or above represents a
strong relationship between two variables.
Table 6 shows the area under the curve for each examiner,
the optimum sensitivity and specificity and the
ICDAS-II cut-off that resulted in this outcome, for the
D1, D3 and ERK 2–3 diagnostic thresholds.
At the D1 diagnostic threshold the optimum sensitivity
and specificity for each examiner was obtained using
ICDAS-II cut-off 1–2. To correctly reflect the D1 diagnostic
threshold all lesions including those with an
ICDAS-II code 1 should have been classed as caries. However,
when this was done, sensitivity was high (mean =
0.89, min. = 0.76, max. = 0.96), but specificity was low
(mean = 0.52, min. = 0.39, max. = 0.61).
The D3 diagnostic threshold used the enamel-dentine
junction to differentiate sound and caries, whereas the
ERK 2–3 diagnostic threshold was deeper, between the
outer third of dentine and middle third of dentine and yet
the same ICDAS-II cut-off gave the optimum sensitivity
and specificity. If a higher ICDAS-II cut-off of 3–4 was
used to reflect this increased severity of lesion when validated
with the ERK 2–3 histological threshold a mean
sensitivity of 0.60 (min. = 0.56, max. = 0.64) and mean
specificity of 0.90 (min. 0.84, max. 0.94) were obtained.
Discussion
Occlusal caries accounts for the majority of new lesions
in the permanent dentition of children, adolescents
and young adults. Whilst one of the most readily accessible
tooth surfaces, it has a complex invaginated anatomy,
which makes caries detection more difficult. There
are numerous treatment options for occlusal caries and
ultimately the aim is to link detection, diagnosis and appropriate
treatment and this study addresses the first step
in this process.
To date little has been published on the visual ICDAS-
II system, but other similar scoring systems have previously
been used. In one study an interexaminer kappa
value of 0.91 and intra-examiner kappa value of 0.9 was
found between 2 examiners using an eight-point scoring
system for diagnosing occlusal caries [Ekstrand et al.,
1995]. Using a five-point scoring system, kappa values of
0.54–0.69 were found for interexaminer reproducibility
of 3 examiners and 0.73–0.89 for intra-examiner agreement
[Ekstrand et al., 1997]. In another study using the
same system, kappa values of 0.47–0.61 between 3 examiners
and 0.56–0.68 for intra-examiner reproducibility
were achieved [Reis et al., 2004]. A recent study which
also used a four-point system for 8 examiners [Souza-
Zaroni et al., 2006], found kappa values of 0.35–0.5
for interexaminer and 0.81–0.85 for intra-examiner reproducibility.
The reproducibility achieved with the
ICDAS-II seven-point scoring system in this study compared
favourably with those cited. However, it is likely
that the cited studies reported unweighted kappa values,
like Ekstrand [1997], since they did not mention weighting.
If we compare the unweighted kappas from the
present study (interexaminer 0.32–0.61; intra-examiner
0.54–0.65), the differences disappear. Although intra-examiner
kappa values could not be calculated for
the reference examiner, this examiner had used the
ICDAS-II system extensively and achieved acceptable
intra-examiner kappa values in a previously published
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ERK 2–3 diagnostic threshold
AUC (SE) CI opt.
sens.
opt.
spec.
ICDAS
cut-off
0.84 (0.04) 0.76–0.93 0.84 0.75 2–3
0.84 (0.05) 0.75–0.93 0.80 0.79 2–3
0.86 (0.04) 0.78–0.94 0.64 0.90 2–3
0.84 (0.04) 0.76–0.92 0.88 0.68 2–3
study [Ekstrand et al., 1997] using comparable visual
criteria. Interexaminer kappa values between the reference
examiner and 3 trained examiners were also acceptable
( table 3 ).
Histological validation of caries and in particular occlusal
caries is notoriously difficult as preparing thin sections
entails tooth tissue loss. Simply hemisecting a tooth
through the lesion may not pass through the deepest aspect
of the lesion in question. Taking a single section
through an investigation site is also problematic if only
one side of the section is examined as the depth of a lesion
will vary from one side of a section to another [Ricketts
et al., 1998]. Whilst only one side of the section was viewed
in this study because of the mounting technique used, the
sections were serial and the side viewed on one section
corresponded to the side not viewed on the preceding
section. These problems arise because of the three-dimensional
nature of the spread of caries dictated by the
complex anatomy of the occlusal surface. A lesion may
originate at one site on the surface of the tooth but spread
obliquely and non-symmetrically beneath the tooth surface.
To overcome this problem and to record the deepest
aspect of the lesion from where it originated at the investigation
site, 1–4 sections were used depending on the
severity of the lesion. The use of the coordinate system
ensured accurate location of each section and thus that
the lesion on the section originated from the investigation
site in question. Because of the mode of spread alluded
to above, it could be argued that the appearance at
one site may influence the decision at another. For example,
if one site was obviously carious, the likelihood of
an adjacent site also being carious and recorded as such
is much higher. The data collected at multiple sites cannot
therefore be regarded as independent. To overcome this
problem one investigation site per tooth was randomly
selected for analysis.
In previous studies comparing both visual classification
systems and histological classification systems of increasing
lesion severity, the relationships between the
two variables have been strong, with Spearman correlation
coefficients of 0.87 for an eight-point visual scale
[Ekstrand et al., 1995] and 0.87–0.93 for a five-point visual
scale [Ekstrand et al., 1997]. In this study the relationship
between the ICDAS-II visual classification system
and either histological classification system was not
as strong (r s = 0.48–0.72 using Downer histology and
0.43–0.68 for ERK histology).
For comparison with other studies using similar visual
classification systems or different novel technologies,
the Downer histology was used in the ROC analyses
for each examiner at the D1 and D3 diagnostic threshold
and the ERK histology was used similarly at the 2–3
threshold. For all examiners the ICDAS-II system produced
areas under the ROC curves in excess of 0.7.
At the D1 diagnostic threshold the mean sensitivity
and specificity of the ICDAS-II were 0.69 and 0.82, respectively
( table 6 ). The sensitivity was found to be higher
than that reported in a previous study using a different
eight-point visual scale and three groups of examiners
[Fyffe et al., 2000b] where sensitivity ranged between 0.46
and 0.5. The specificity in this study was similar to that
reported by Fyffe et al. [2000b], who found specificities
of 0.66–0.86. However, in this study optimum sensitivity
and specificity were achieved at the ICDAS-II cut-off 1–2
and not 0–1, which would have been consistent with the
D1 diagnostic threshold. When the 0–1 cut-off was used,
sensitivity was high (mean = 0.89), but specificity was low
(mean = 0.52). This means that a large number of sound
sites were incorrectly scored as carious and this may have
been due to stained sites, areas of fluorosis or developmental
defects being incorrectly scored as caries. It is important
to question what impact this would have clinically.
From table 4 it can be seen that the sound sites
that were incorrectly scored as carious were given a low
ICDAS-II score which would not require operative treatment.
The worse clinical outcome would therefore be giving
prevention to a sound site, which in a high-risk patient
would be of benefit.
In this study, at the D3 diagnostic threshold mean sensitivity
was 0.70 and specificity was 0.89 using ICDAS-II
scores 2–3 to differentiate sound sites from those with
dentine caries ( table 6 ). These are similar to those reported
by Downer [1989], who in a review of the literature
found that trained and experienced examiners using a
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visual method of diagnosis can detect dentine caries with
a sensitivity in excess of 0.6 and a specificity in excess of
0.8 in a sample of borderline lesions.
In the Downer histology the enamel-dentine junction
is taken as a diagnostic threshold to calculate diagnostic
accuracy at the D3 level (code 2–3), whereas in the ERK
histological system the enamel-dentine junction is not
used and the histological threshold 2–3 corresponds to
deeper dentine lesions (a threshold between outer third
of dentine and middle third of dentine). Despite this, similar
levels of sensitivity and specificity were obtained
when the same ICDAS-II cut-off 2–3 was used. Using
these ICDAS-II cut-offs and ERK histological threshold
allowed comparison with previous work where higher
sensitivity (0.92–0.97) and specificity (0.85–0.93) values
were obtained [Ekstrand et al., 1997]. In the present study,
when a higher ICDAS-II cut-off 3–4 was used, specificity
values increased to a mean of 0.90 at the expense of sensitivity,
which fell to a mean of 0.60. However, the level of
overall accuracy (sensitivity plus specificity) was of the
same order of magnitude as when ICDAS-II cut-off 2–3
was used.
A review of studies that included the validation of diagnostic
techniques against a histological gold standard
[Ie and Verdonschot, 1994] showed that visual inspection
performed comparatively poorly for occlusal caries diagnosis
compared to electrical resistance measurements
and fibre-optic transillumination. In addition to this, another
systematic review of the literature has shown that
for visual examination specificity is high but sensitivity
is low [Bader et al., 2001]. In these two reviews meta-analyses
have either not been carried out or the results should
be regarded with caution because of the heterogeneity of
the studies included. However, it would appear that in
general, visual examination has been regarded as poor for
caries detection. In contrast, this study has shown that by
meticulously examining clean dry teeth sensitivity of a
visual examination can be improved after a short training
period.
In summary, after a relatively short training period 3
examiners were able to achieve results using the ICDAS-
II system that were comparable to that of the examiner
carrying out the training. The ICDAS-II system demonstrated
reproducibility and diagnostic accuracy for the
detection of occlusal caries at varying stages of the disease
process comparable to those published in previous
studies using similar visual criteria. The moderate to
strong relationship with histological extent also demonstrates
its potential to monitor lesions with time. With the
development of more extensive and advanced training
packages and calibration exercises there may be scope to
improve the reproducibility and accuracy further. In addition,
such packages would allow further dissemination
of ICDAS-II, allowing data from clinical studies in primary
dental care, clinical trials and epidemiological surveys
to have greater clarity and comparability for metaanalyses.
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