A. Lussi et al., Performance and reproducibility of a laser fluorescence system for detection of occlusal caries in vitro, CARIES RES, 33(4), 1999, pp. 261-266
The diagnosis of occlusal caries at non-cavitated sites remains problematic
, especially since clinical visual detection has limited sensitivity. Elect
rical methods of detection show considerable promise, but specificity is re
duced. The aims of this in vitro study were: (1) to assess the validity of
a new laser fluorescence device - the DIAGNOdent - (and compare the values
with those of a fixed-frequency electrical device); (2) to determine the op
timum cut-off points of the new device for different stages of the caries p
rocess, and (3) to assess the reproducibility of the new laser device. For
validity and determination of optimum cut-off points, 105 extracted teeth w
ith macroscopically intact occlusal surfaces were measured by a single exam
iner, using both the laser fluorescence device (on both moist and dried tee
th) and an Electronic Caries Monitor. The teeth were subsequently examined
histologically to determine the specificity, sensitivity and likelihood rat
io at the D-2 (caries extending through more than half of the enamel thickn
ess) and D-3 (caries involving dentin) levels. The values obtained for the
laser device ranged from 0.72 to 0.87 (specificity), 0.76 to 0.87 (sensitiv
ity) and 3.0 to 5.6 (likelihood ratio). Those for the ECM ranged from 0.64
to 0.78 (specificity), 0.87 to 0.92 (sensitivity) and 2.4 to 4.1 (likelihoo
d ratio). To determine intra- and interexaminer reproducibility of the DIAG
NOdent, 11 dentists recorded two different measurements at the same site on
a separate set of 83 extracted molar teeth, and these were compared using
Cohen's kappa (at D-2 and D-3 levels) and Spearman's correlation coefficien
t. The average intra-examiner kappa scores were 0.88 (D-2) and 0.90 (D-3),
with a Spearman correlation of 0.97. For interexaminer reproducibility, the
average kappa values were 0.65 (D-2) and 0.73 (D-3), with a Spearman corre
lation of 0.84. It is concluded that for occlusal caries (1) the new laser
device has a higher diagnostic validity than the ECM, and (2) in vitro, mea
surements using the device are highly reproducible. Thus, the laser device
could be a valuable tool for the longitudinal monitoring of caries and for
assessing the outcome of preventive interventions.