Assessment of two methods for detecting carious dentin: an in vitro study

Abstract

Background
The objective of this study was to compare, in vitro, two dentinal caries lesion detector methods, Caries Finder and BlueCheck, to determine if they were substantially equivalent in their ability to aid visualization of demineralized dentin and to also to compare their performance compared to the traditional visual/tactile method of dentinal caries lesion detection in vitro.

Methods
Sixty-five extracted human teeth containing lesions rated as ICDAS 4,5 or 6 were chosen and then randomly assigned to two groups. Specimens were then evaluated in standard operatory conditions by three evaluators using the traditional visual and tactile method, the Caries Finder method, and the BlueCheck method of detection. The study employed a parallel, randomized controlled study design. To test the equivalence claim, a “two-one sided test” (TOST) approach was utilized.

Results
As compared to the traditional method, the Caries Finder method had a 0.9742 accuracy, 95% confidence interval [0.9578, 0.9855], 94.80% sensitivity, 98.53% specificity, 96.47% positive predictive value, 97.82% negative predictive value, 0.938 Kappa value, p < 2.2e-16). The BlueCheck method had a 0.9821 accuracy, 95% confidence interval [0.9682, 0.9910], 96.02% sensitivity, 99.09% specificity, 97.69% positive predictive value, 98.42% negative predictive value, 0.956 Kappa value, p < 2.2e-16). Inter-rater reliability and intra-rater reliability ratings were good to excellent.

Conclusions
The results of this study support the conclusion that the Caries Finder and BlueCheck methods compare favorably with the traditional method of carious dentin detection. Caries Finder and BlueCheck detection methods were found to have comparable performance in their ability to differentiate carious dentin from healthy tooth structure in vitro; however further in vivo validation is required to confirm clinical equivalence. Both show good to excellent inter-rater and intra-rater reliability.

Full text

Whiteetal. BMC Oral Health (2025) 25:258
https://doi.org/10.1186/s12903-025-05596-0
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BMC Oral Health
Assessment oftwo methods fordetecting
carious dentin: aninvitro study
Joel White1, Alfa Yansane1, Puja Kukreti2, Pragati Nahar2, Paolo Orobia2, Rachel Jensen3, Leslie Plack1,
Ram Vaderhobli1, Jonathan Magnum4 and Larry Jenson1,5*
Abstract
Background The objective of this study was to compare, in vitro, two dentinal caries lesion detector methods, Caries
Finder and BlueCheck, to determine if they were substantially equivalent in their ability to aid visualization of deminer-
alized dentin and to also to compare their performance compared to the traditional visual/tactile method of dentinal
caries lesion detection in vitro.
Methods Sixty-five extracted human teeth containing lesions rated as ICDAS 4,5 or 6 were chosen and then ran-
domly assigned to two groups. Specimens were then evaluated in standard operatory conditions by three evaluators
using the traditional visual and tactile method, the Caries Finder method, and the BlueCheck method of detection.
The study employed a parallel, randomized controlled study design. To test the equivalence claim, a “two-one sided
test” (TOST) approach was utilized.
Results As compared to the traditional method, the Caries Finder method had a 0.9742 accuracy, 95% confidence
interval [0.9578, 0.9855], 94.80% sensitivity, 98.53% specificity, 96.47% positive predictive value, 97.82% negative pre-
dictive value, 0.938 Kappa value, p < 2.2e-16). The BlueCheck method had a 0.9821 accuracy, 95% confidence interval
[0.9682, 0.9910], 96.02% sensitivity, 99.09% specificity, 97.69% positive predictive value, 98.42% negative predictive
value, 0.956 Kappa value, p < 2.2e-16). Inter-rater reliability and intra-rater reliability ratings were good to excellent.
Conclusions The results of this study support the conclusion that the Caries Finder and BlueCheck methods com-
pare favorably with the traditional method of carious dentin detection. Caries Finder and BlueCheck detection
methods were found to have comparable performance in their ability to differentiate carious dentin from healthy
tooth structure in vitro; however further in vivo validation is required to confirm clinical equivalence. Both show good
to excellent inter-rater and intra-rater reliability.
Keywords Cavitated caries lesion, Caries lesion, Minimally invasive dentistry, Dentin, Detection dye
Background
e new clinical paradigm of managing dental caries in
the least invasive way has led to the quest to find new
methods of detecting carious lesions earlier and more
effectively than the traditional methods of detection.
is invitro study was initiated to determine substan-
tial equivalency between a novel carious dentin lesion
detection dye and a more established detection dye. It is a
necessary first step towards eventual clinical trials of this
new technology.
*Correspondence:
Larry Jenson
ljenson@sonic.net
1 Department of Preventive and Restorative Dental Sciences, UCSF School
of Dentistry, 707 Parnassus Avenue, San Francisco, CA 94105, USA
2 UCSF School of Dentistry, 707 Parnassus Avenue, San Francisco, CA
94105, USA
3 Centre for Biopharmaceutical Excellence, Level 11, 655 Elizbeth St,
Melbourne 3000, Australia
4 Incisive Technologies Pty Ltd, Level 6, 41 Exhibition Street, Melbourne,
VIC 3000, Australia
5 Richmond, Sonoma Street, CA 94805, USA
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e history of using dyes to aid the visualization of
carious dentin is, at best, controversial [1–5]. Dyes have
been shown to lack a degree of sensitivity and specificity
that would give a clinician the confidence that any den-
tinal structure stained by the dye was indeed “diseased”
[2].
Originally intended to differentiate dentinal tissue that
was infected with bacteria from tissue that was either
healthy or merely demineralized, dyes were thought to
be essential to the proper management of carious den-
tin lesions wherein all infected dentin was to be removed
before restoration to prevent progression of the lesion
[6, 7]. Subsequent studies showed that dyes (usually 1%
acid red in propylene) did not actually detect bacteria
nor did they necessarily detect denatured collagen that
was beyond remineralization (another reason for tissue
removal) [3, 8, 9]. Later studies supported the idea that
dyes merely indicated increased porosity of the dentinal
lesion [4, 10–12]. Consequently, and ironically, the use of
these dyes would often lead to excess tissue removal as
any area of dentin porosity would become stained. It has
been shown that the potential for removing healthy or
re-mineralizable tooth structure when using these dyes is
significant, thus leading to complications.
In the modern paradigm of caries management, the
progression of caries lesions is understood to be a func-
tion of the biofilm and oral conditions that fuel the dem-
ineralization process (caries) and not the presence of
bacteria within the carious lesion [13–16]. As a result,
complete removal of the carious lesion is no longer the
standard of care for stopping lesion progression [17–23].
Non-restorative (non-surgical) therapies are now focused
on the control of the biofilm, oral conditions, and other
risk factors in order to stop lesion progression. Moreover,
the use of silver diamine fluoride and other techniques
has further lessened the need for extensive surgical pro-
cedures as these methods are capable of arresting and
reversing demineralization without tissue removal [17].
It would seem that the use of detection dyes has little or
no role to play in the new paradigm of minimally invasive
caries management.
And yet, the ability to differentiate healthy from carious
dentinal tissue is still important in many other ways, and
detection dyes may prove to be important strategies in
the new paradigm of caries management and minimally
invasive dentistry. First, areas of carious dentin indicate
that the caries process is ongoing. Active lesion iden-
tification (whether in enamel or dentin) is important in
diagnosis and caries risk assessment in that it indicates
that the patient is “out of balance” and thus at higher risk
for lesion formation and progression and would ben-
efit from therapies intended to improve that balance [24,
25]. As therapies are introduced, monitoring of those
therapies is informed by the presence or absence of active
lesions. Detection dyes have the potential to contribute
to the monitoring of lesion activity, the effectiveness of
therapeutic interventions and patient education efforts,
though future invivo research is needed to validate these
roles. Second, the traditional method for identifying
active dentin lesions utilizes visualization and probing
with a dental explorer. is method is limited in several
ways. Visualization is limited by the large variance in
color and appearance of demineralized and healthy den-
tin [26]. e use of a dental explorer to determine dem-
ineralization is limited in two ways; studies have shown
that the sensitivity of this method is poor [27] and that
using it risks exacerbating the carious process [28–32]. It
is generally accepted that aggressive probing with a sharp
instrument for enamel or dentinal lesions is contraindi-
cated as a routine procedure. Lastly, the presence of cari-
ous dentinal tissue can indicate an area that might thwart
restorative goals [19]. It is well known that demineral-
ized dentin can undermine enamel structure and existing
restorations. It has also been shown that demineralized
dentin can compromise the marginal seal and reten-
tion of restorations dependent on adhesive techniques,
and if there is extensive demineralization, the compres-
sive strength of a restoration can be diminished [33–36].
Safer and more effective methods of detecting deminer-
alized dentin are clearly needed in the new paradigm of
caries management.
e study presented here was an opportunity to inves-
tigate and compare the carious dentin-detecting ability of
two detection dyes: a traditional dye, Caries Finder (CF)
and a novel dye, BlueCheck (BC). Each was compared
to the traditional method (TM) of carious dentin detec-
tion using unaided visualization and tactilization. e
Caries Finder method and the BlueCheck method were
also compared to each other to determine if they were
substantially equivalent in their ability to aid visualiza-
tion of carious dentin invitro. e traditional method of
evaluating dentin lesions was used in the study as a gold
standard. Despite several technologies that have been
introduced to improve lesion detection, the traditional
method is still the most commonly used method for den-
tin lesion evaluation [1, 26, 37].
Caries Finder (Danville Materials, San Ramon, CA)
is a patented, contemporary version of the time-tested
solution of either 1% acid red or 1% FD&C green in pro-
pylene glycol. Caries Finder is intended to be used in
cavity preparation to identify carious dentin. e manu-
facturer states that this product stains the collagen that is
exposed in the carious process of demineralization. It is
postulated that the dye molecules have a unique affinity
for loose collagen present within areas of demineralized
dentin.
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BlueCheck (Incisive Technologies Pty Ltd, Melbourne,
Victoria, Australia) is a new product for detecting dem-
ineralized dentin and is intended to aid the visualization
of carious lesions in enamel and dentin. It is a solution
that is intended as a “porosity probe” applied directly
to a tooth to identify areas of demineralization in both
enamel and dentin and hypo-mineralized dental tissues
under white light in standard clinical environments.
BlueCheck solution contains an engineered biomolecule
that consists of a deep-blue dye (Amido black) linked
to a protein (hemoglobin) that has a specific affinity for
porous hydroxyapatite. BlueCheck utilizes the natural
hydroxyapatite-binding chemistry of proteins to specifi-
cally and reversibly bind to porous dental hydroxyapa-
tite. It does not rely upon the presence of bacteria, acid/
bacterial byproducts, or collagen. e intensity of the
staining is correlated to the degree of demineralization
[38]. BlueCheck is intended to be applied to teeth at an
initial examination to reveal areas of demineralization
in enamel and dentin and to be used to monitor lesions
following therapeutic efforts. It also has the potential to
be used during cavity preparation to reveal areas that are
demineralized. BlueCheck is fully reversible and can be
easily removed by following the instructions for use.
Both BlueCheck and Caries Finder stain demineralized
dentin progressively with darker color indicating a higher
degree of demineralization. Both dyes are applied follow-
ing cleansing the tooth of plaque/biofilm. e application
process for both dyes requires minimal training and both
can be used in any clinical environment where there is
adequate lighting and water supply.
e objective of this study was to compare the carious
dentin lesion detection ability of the BlueCheck method
and the Caries Finder method to the traditional method
of carious dentin lesion detection, and to each other
through the sensitivity (Se), specificity (Sp), positive pre-
dictive value (PPV), and negative predictive value (NPV)
of each method. Inter-rater and intra-rater reliabilities for
each method were also assessed.
Methods
Specimen selection, randomization, andassignment
togroups
Sixty-five specimens of extracted human permanent
teeth with cavitated smooth surface carious lesions were
selected by three dentists trained in the International
Caries Detection and Assessment System (ICDAS) from
a biobank of teeth at the University of California, San
Francisco School of Dentistry. Specimens were previ-
ously sterilized in an autoclave and stored in 0.1% thymol
aqueous solution. Agreement of ICDAS score by 2 of 3
dentists was required for specimen inclusion in the study.
All selected teeth had one smooth surface lesion that met
the ICDAS 4, 5, or 6 criteria for cavitated lesions: visu-
ally evident enamel breakdown with indications of den-
tin involvement [39]. Specimens were required to have
lesions that had a periphery of either healthy enamel
(ICDAS 0) or early enamel disease (ICDAS 1 or 2). Speci-
mens were randomized by computer assignment and
then assigned into 2 groups (BC and CF) with near-equal
numbers of specimens. Each specimen was assigned a
unique identification code.
Preparation, photography, andgrid placement
For evaluation, each specimen was cleaned and dried and
then placed in a rigid wax mold and photographed at a
repeatable distance. e resulting images were digitally
overlaid with a standardized (2 mm × 2 mm) positional
grid pattern demarcating areas to be examined (squares).
Each specimen and its corresponding photograph were
then evaluated by all three examiners and scored. ese
scores became the gold standard for the investigation.
Scoring was determined by the presence or absence of
“diseased” (demineralized/carious) dentin within any
given grid area (square): DD for diseased dentin and
NDD for not diseased dentin. A square that had diseased
cementum or enamel or healthy enamel was designated
as NDD. Any square that could not be determined to be
either DD or NDD was not included in the analysis and
a red “x” was placed in that square for the next round of
evaluations using BC or CF. BC or CF was then applied to
the teeth as per group assignment and as per the manu-
facturer’s instructions. Specimens were then returned
to their rigid wax molds and photographed again at the
original distance. e resultant images were then digi-
tally overlaid with the original grid pattern that was used
to evaluate TM, and then evaluated and scored. Figure1
shows the experimental sequence and data collection
workflow.
Examiners, calibration andscoring
ree experienced dental clinicians, trained and cali-
brated in ICDAS, were asked to be examiners for the
study which was conducted in a standard clinical setting
with available operatory lights and a computer screen
for displaying the comparison images. Examiners were
calibrated for the study using specimens outside of those
selected for the study. Calibration of examiners included
a review of literature and the examination of photographs
of healthy and diseased enamel and dentin that have been
stained. Calibration of presence or absence of stain deter-
mination occurred during pilot studies with review of
concordant and discordant observations by examiners.
Examiners were provided with specimens, a dental
mirror, a dental explorer, periodontal probes, loupes, and
compressed air syringes. ey were allowed to handle
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and manipulate the specimens as they viewed the com-
parison images on the computer screen. For the first
round of evaluation, examiners independently scored the
image grid for each specimen without BC or CF applied.
ese scores became the standard against which scores
for BC and CF were compared. For the second round of
evaluations, one designated evaluator applied BC to the
specimens in that group and then all examiners would
independently score the image grid squares for those
specimens. For the third round of evaluations, the same
designated examiner would apply CF to the specimens in
that group and then all evaluators would independently
score the image grid squares for that group of specimens.
Examiners scored each square of the grid for each
specimen for diseased dentin (DD) or not diseased den-
tin (NDD). A positive determination of disease required a
predominance (≥ 50%) of disease within the square. Fig-
ure2 shows examples of typical grided images for TM,
BC and CF. Squares containing a red X were not scored.
For the test–retest assessment, each examiner repeated
their scoring on four randomly selected specimens within
each group.
Statistical methods/analysis
Sample size calculation
We employed a parallel, randomized controlled study
design with a 1 to 1, BC to CF ratio to evaluate the equiv-
alence of the methods. e unit of randomization was the
dental tooth. All eligible teeth were simultaneously rand-
omized by computer-generated assignment at the time of
the trial. e analysis estimated the proportion of detec-
tion using the two methods BC and CF. e sample size/
power calculations were based on the estimated number
of teeth cleaned, imaged and available for analysis. To
Fig. 1 Flow chart showing the workflow for the comparison of BC and CF versus TM
Fig. 2 A is a photograph of an untreated specimen before and after
the application of BC with an overlaid grid and scores of either DD
or NDD. B is a photograph of another specimen before and after
the application of CF with an overlaid grid and scores of either DD
or NDD. Grid areas with a red X were not scored
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perform the power analysis, investigators reported the
detectable difference for the fixed sample size of 65 teeth
and an assumed 90% power. e total sample of 65 teeth
yielded 1,215 (CF: 590, BC: 625) square sized surfaces
for demineralization detection by reviewers. ere were
8 unusable surfaces found among the CF cohort and 10
among the BC cohort yielding a final sample of 65 teeth
and 1197 surfaces (CF: 582, BC: 615). Given the 65 teeth
and the 1197 surfaces, an assumed power to detect dif-
ferences of 90%, a standard significance level of 0.05, the
two one-sided test will be able to detect a difference of
0.09.
Examiner reliability
To determine intra-examiner reliability, 10% of samples
were re-evaluated a second time by each examiner.
Statistical methods
e diseased dentin outcome was measured as a binary
variable: presence or absence of staining with clinician
evaluator assessment as stained indicating carious lesion.
To test the equivalence claim in the trial comparing two
different methods for carious lesion detection, a “two-
one-sided test” (TOST) approach was utilized [40]. We
report the proportion of diseased dentin with both the
BC and CF methods along with their absolute difference.
e equivalence margin is set at 15% (delta = 15.0%). A
two-sided 90% confidence interval was used to establish
whether equivalence is satisfied at the 5% significance
level. Additionally, the sensitivity of both BC and CF in
the detection of diseased dentin was compared using
the same two-one-sided test approach. If the result con-
fidence limits include the given 15% delta, then there is
evidence that the two methods are equivalent.
e traditional method, with no intervention compared
to the two interventions, was used to calculate sensitivity.
For TM, no intervention on all teeth before the applica-
tion of intervention establishes the gold standard with a
2/3 evaluator agreement for each grid assessment. ese
statistical methods to determine sensitivity were used for
the healthy dentin collected. e same methodology was
utilized to determine sensitivity, positive predictive value
(PPV) and negative predictive value (NPV).
Results
Descriptive statistics
A total of 65 teeth containing 70 lesions were examined
and scored for each square. e total number of squares
examined for all methods was 1197 with 582 squares for
CF and 615 squares for BC. Tables1 and 2 show an over-
view of the data used for statistical analysis.
Statistical analysis: Two‑One‑Sided Approach (TOST)
ere were 164 out of 173 measurement areas accu-
rately (as compared to TM) diagnosed as diseased den-
tin using CF: 0.9742 accuracy, 95% confidence interval
[0.9578, 0.9855], 94.80% sensitivity, 98.53% specificity,
96.47% positive predictive value, 97.82% negative predic-
tive value, 0.938 Kappa value, p < 2.2e-16). Using BC, 169
out of 176 diseased dentin measurements were accurately
diagnosed using BC: 0.9821 accuracy, 95% confidence
interval [0.9682, 0.9910], 96.02% sensitivity, 99.09% spec-
ificity, 97.69% positive predictive value, 98.42% negative
predictive value, 0.956 Kappa value, p < 2.2e-16). Figure3
displays the measure scores of BC and CF compared
to the gold standard TM. It shows that the BC and CF
methods are comparable to the reference standard (TM)
in their ability to differentiate diseased dentin from non-
diseased dentin. Sensitivity, specificity, NPV and PPV
values for BC and CF are all above 94%. Figure4 shows
that BC is substantially equivalent (non-inferior) to CF.
Reliability
Tables3 and 4 are summaries of inter-rater and intra-
rater reliability analyses.
ese results show that both the BlueCheck method
of detection and the Caries Finder method of detection
compares favorably to the traditional method of carious
dentin detection. As for the inter-rater reliability of the
methods studied, Table3 shows good agreement between
evaluators for BC, CF, and TM. Values above 0.75 are
good according to the guidelines from Landis and Koch
1977 [41]. Table 4 shows good to excellent intra-rater
reliability.
Discussion
e ability to clinically determine the existence and
extent of carious dentin is essential to modern car-
ies management strategies. Even though the traditional
method of carious dentin detection is still the most com-
monly used, it suffers from less-than-ideal reliability and
involves the use of a dental explore that can further dam-
age carious tissue. Safer and more effective methods of
carious dentin detection are being sought. is study was
Table 1 Total number of squares evaluated by method and
group
Total Teeth 65
Total number of lesions 70
Total number of squares evaluated that met
the inclusion criteria 1197
Total number of squares evaluated by method TM 1197
CF 582
BC 615
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an opportunity to investigate a novel method of detec-
tion and compare it to two of the methods currently
being used. e results of this study support the conclu-
sion that the BlueCheck method of detection compares
favorably to the traditional and the Caries Finder meth-
ods of detection.
When interpreting the findings of studies like this
one, sensitivity and specificity values must be consid-
ered in the context of what the dye seeks to disclose. e
assumption in this study is that these two methods seek
to identify dentin that has been demineralized by the
carious process. It is entirely possible that all three meth-
ods also identify areas of dentin that are hypo-mineral-
ized by some other process. is study is a comparison
study only: the results show that both the BlueCheck and
Caries Finder methods are at least as good as the tradi-
tional method and at least as good as each other. is is
a necessary first step towards future studies that might
establish the superiority of the methods used here. We
are clear that none of the methods studied seek to detect
caries. It is unfortunate that the word “caries” has been
used to refer to both the disease process and the demin-
eralization of tissues that the caries process creates. is
conflation of meanings has led to meaningless terms such
as “residual caries”, ambiguous terms such as “recurrent
caries”, and dyes being erroneously referred to as “caries
detectors”. Caries is a diagnosis made by a dentist con-
sidering all clinical findings: no dye can do this directly.
At best, dyes can give information to the dentist that
informs that diagnosis. We suggest that a caries diagnosis
indicates an ongoing process of demineralization. Tooth
tissues that evidence demineralization can, though not
always, indicate that the process is active. We know that
in the absence of the demineralization process, enamel
and dentin will remineralize and form an impermeable
layer. We also know that detection dyes like Caries Finder
and BlueCheck will generally fail to stain structures that
have an impermeable layer of remineralization [38, 42].
In the new paradigm of caries management, detection
dyes can be valuable if their intended target is an area
of demineralization suspected to be caused by the car-
ies process and the dentist only utilizes this information
within the context of clear therapeutic aims: diagnostic,
preventative, surgical and/or restorative.
is study is limited in that it is an invitro study and
results may be different when either of the two methods
is used clinically. Future invivo studies are needed to
fully evaluate the clinical effectiveness of either method.
Invivo studies are a necessary direction for future study.
e use of the TM as a gold standard is limited and future
Table 2 Total squares evaluated as DD and NDD by method and group
Number of squares evaluated as diseased dentin (DD) by method and group CF group BC group
CF TM BC TM
164 173 169 176
Number of squares evaluated as not-diseased dentin (NDD) by method and group 403 409 435 439
Fig. 3 Measure scores of sensitivity, specificity, positive predictive value, and negative predictive value of BC and CF compared to the gold
standard, TM
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studies that employ gold standards such as histological
analysis and those that quantify the extent of deminerali-
zation would give a clearer assessment of the efficacy of
the two methods examined here. No attempt was made
to differentiate between demineralized dentin caused by
a disease process and naturally occurring demineralized
areas such as those found near the DEJ and peri pulpally.
No attempt was made to quantitatively correlate the
intensity of the staining with the extent of demineraliza-
tion; this would also be a good direction for future stud-
ies. Given studies like Kidd 1989 [43] showing that, as
compared to detection dyes, the traditional method fails
to detect all demineralized tissue, we might expect a high
level of false positives leading to lower values of specific-
ity. is was not the case in this study: specificity values
were high for both dyes.
e clinical significance of the results presented here
is that both methods of dye detection are equivalent and
compare favorably to the traditional method. us, den-
tists now have a variety of methods available for carious
dentin detection. It may be that each method has clini-
cal advantages over the others. For example, using either
BlueCheck or Caries Finder instead of the traditional
method may significantly lower the need for probing
dentin with a sharp explorer. As mentioned above, know-
ing the mineralization state of the dentin may prove to be
Fig. 4 95% confidence interval of specificity, sensitivity, positive predictive value and negative predictive value outcome difference between BC
and CF
Table 3 Summary of the inter-rater reliability analysis
Inter‑Rater Reliability by Method
TM
Value Lower Bound Upper Bound
ICC (Absolute Agreement) 0.830 0.812 0.847
ICC (Consistency) 0.835 0.820 0.849
CF
Value Lower Bound Upper Bound
ICC (Absolute Agreement) 0.821 0.796 0.844
ICC (Consistency) 0.826 0.803 0.846
BC
Value Lower Bound Upper Bound
ICC (Absolute Agreement) 0.876 0.860 0.891
ICC (Consistency) 0.876 0.860 0.891
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an essential aid to caries risk assessment, caries diagno-
sis, monitoring therapeutic interventions and restorative
success. Moreover, the ability to visualize demineraliza-
tion more clearly could be beneficial for patient educa-
tion efforts and the training of new dentists.
ere are many aspects of the two products studied
here that could be pursued in future studies. An invivo
study could focus on the effects of oral conditions (saliva,
plaque, etc.) and patient comfort and sensitivity. A usa-
bility study could address issues of provider training, ease
of application, cost-effectiveness, best practices, patient
education and effective disposal of surplus product.
Long-term studies could investigate the effects these dyes
have on restoration and tooth survival as well as success
at monitoring lesions over time. Another study could
examine the benefit of combining the detection dyes with
other modalities such as DIAGNOdent, optical coher-
ence tomography or bioluminescence and relate positive
detection to staining intensity. Still another study could
pursue the integration, benefits and economics of these
products in large-scale public health initiatives and use in
pediatric dentistry.
ere is nothing automatic about using carious dentin
dyes; it is still up to the dentist to decide if, where and
how much dentin might need to be removed to achieve
treatment goals [23]. And, it is still up to the dentist to
make a diagnosis of “caries”: an assessment that the
patient is experiencing an ongoing process of tooth dem-
ineralization due to acids produced by bacteria and not
by some other pathological process. For example, both
methods would presumably identify areas of dentin that
were demineralized due to acid erosion. Detection dyes
merely help indicate the presence of porosity: permeable,
demineralized enamel and dentin. Healthy dentin can
include areas of reduced mineralization (pulpal and DEJ
areas) and so the use of these dyes requires expert clini-
cal judgment to determine the proper management of the
lesion and maximize their potential in the new paradigm
of minimally invasive caries management. e two dyes
assessed in this study can best be utilized to confirm the
initial clinical judgment of the dentist.
Conclusions
e results of this study support the conclusion that Car-
ies Finder and BlueCheck, intended as aids to the visuali-
zation of demineralized dentin, compare favorably with
the traditional method of demineralized dentin detec-
tion. e results suggest that BC and CF have comparable
performance invitro to differentiate carious dentin from
healthy tooth structure.; however, further invivo valida-
tion is required to confirm clinical equivalence. Both CF
and BC show good to excellent inter-rater and intra-rater
reliability. ese findings indicate that BC and CF are
promising methods for detecting demineralized dentin
in vitro. Further studies, particularly in vivo investiga-
tions, are necessary to validate their clinical applicability
within the paradigm of minimally invasive dentistry. Both
the Caries Finder method and the BlueCheck methods
of detection may play an important role in the new para-
digm of minimally invasive dentistry when diagnostic
and therapeutic goals are clearly articulated. ese meth-
ods have the potential to contribute to minimally invasive
dentistry, particularly for aiding visualization of demin-
eralized dentin. However, clinical trials are needed to
confirm their practical utility and impact on patient out-
comes. Future invivo studies will build an understanding
of their use in clinical practice within the minimally inva-
sive paradigm of caries management.
Abbreviations
CF Caries Finder
BC BlueCheck
TM Traditional Method
Se Sensitivity
Sp Specificity
PPV Positive Predictive Value
NPV Negative Predictive Value
Table 4 Summary of intra-rater reliability analysis with lower and upper bounds of confidence interval
Intra‑Rater Reliability
Examiner 1 Examiner 2 Examiner 3
TM
ICC (Absolute Agreement) 0.889 (0.823, 0.931) 0.939 (0.913, 0.957) 0.887 (0.820, 0.930)
ICC (Consistency) 0.888 (0.822, 0.931) 0.938 (0.912, 0.957) 0.889 (0.822, 0.931)
CF
ICC (Absolute Agreement) 0.954 (0.923, 0.972) 0.788 (0.651, 0.873) 0.965 (0.928, 0.983)
ICC (Consistency) 0.954 (0.925, 0.973) 0.800 (0.677, 0.880) 0.965 (0.928, 0.983)
BC
ICC (Absolute Agreement) 0.890 (0.815, 0.934) 1.000 0.877 (0.775, 0.935)
ICC (Consistency) 0.898 (0.835, 0.937) 1.000 0.883 (0.787, 0.938)
Content courtesy of Springer Nature, terms of use apply. Rights reserved.

Page 9 of 10
Whiteetal. BMC Oral Health (2025) 25:258
ICDAS International Caries Detection and Assessment System
DD Diseased Dentin
NDD Not Diseased Dentin
TOST Two-One-Sided-Test
Acknowledgements
Acknowledgements: The authors would like to acknowledge Felicity Crombie
for her contributions to the analysis of this paper. This work was supported by
an Institutional Research Grant to UCSF by Incisive Technologies, the Raymond
L. and Mary V. Bertolotti Distinguished Professorship in Restorative Dentistry
and the UCSF student summer fellowship.
Authors’ contributions
Author Contributions: Authors JW, JM, RJ and AY contributed to the concep-
tion, methodology, formal analysis, and writing of the manuscript. Authors PK,
PO and PN contributed to the investigation of the study, data curation and
writing of the manuscript. Author LJ contributed to the formal analysis and
writing of the manuscript. All authors collaborated in the writing of the manu-
script, critically revised the manuscript, gave final approval of the manuscript,
and hereby agree to be accountable for all aspects of the work.
Funding
Funding for this study was provided to UCSF through the Industry Contract
Division by a Services Agreement between The Regents of the University of
California and Incisive Technologies, Pty. Ltd.
Data availability
The datasets used and/or analysed during the current study are available from
the corresponding author on reasonable request.
Declarations
Ethics approval and consent to participate
Ethical approval was not required as the study was not human subjects
research and therefore not FDA-regulated. Institutional Review Board was
not required for using de-identified tooth specimens in an in vitro study. The
samples used in this study were collected by the University of California, San
Francisco School of Dentistry. Permission to use these materials was obtained
from the University of California, San Francisco School of Dentistry.
Consent for publication
Not applicable for this study.
Competing interests
Competing Interest Statement: Authors who are employees of Incisive
Technologies and the independent statistical consultant paid by Incisive Tech-
nologies Pty Ltd, participated in the study design, analysis, review and editing
of the manuscript. Author JM was an employee of Incisive Technologies Pty
Ltd. at the time of the study and has no financial interest in Danville Materials
Inc. Author RJ is a paid consultant for this paper and has no financial interest
in Incisive Technologies Pty Ltd or Danville Materials Inc. Author LJ is an
independent writing consultant paid, for this study, by Incisive Technologies
Pty. Ltd. and has no other financial interest in Incisive Technologies Pty Ltd. or
Danville Materials Inc. Authors, PK, PO, and PN are dental students at UCSF and
have no financial interest in Incisive Technologies Pty Ltd. or Danville Materials
Inc. Authors, JW and AY, RV and LP are employees of UCSF and have no finan-
cial interest in either Incisive Technologies Pty Ltd. or Danville Materials Inc.
Received: 27 August 2024 Accepted: 3 February 2025
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