Measurement of histological and radiographic depth and width of occlusal caries lesions: a methodological study

To develop a measurement method to quantify the depth and width of occlusal caries lesions.

One hundred and ten extracted permanent molars with occlusal caries lesions were selected, then visually scored by ICDAS scoring system and then sectioned mesiodistally, resulting in a facial and a lingual fraction. Digital photos and radiographs were taken from each section. By randomization, one of the sections was chosen for further examinations. First digital photos were taken. Depth and width of the lesions were marked with arrows on the images both before (H(un-col)) and after coloring (H(col)) the sections. The same types of measurements were done on the radiographs (R). The relative dentinal depth and width of the lesions were measured in the same order.

Weighted intra- and interexaminer kappa value for ICDAS scorings varied between 0.85 and 0.90. Intraexaminer kappa for dentinal depth in 36 randomized selected teeth was calculated to 0.75 (H(un-col)), 0.91 (H(col)), 0.79 (R) and for dentinal width to 0.84 (H(un-col)), 0.96 (H(col)), 0.84 (R). Significant correlations were found between ICDAS scorings and the measurements of depth and width of lesions in H(un-col), H(col), and R (p < 0.000). The lowest difference was measured between H(un-col) and H(col) in both relative depth and width of the lesion with maximum differences up to 45% (H(un-col)-H(col)) and 73% (H(col)-R).

It is possible to measure depth and width of occlusal caries lesions by means of histological and radiographic technique with acceptably high reproducibility using this method.