Laboratorial training of examiners for using a visual caries detection system in epidemiological surveys

In epidemiological surveys, a good reliability among the examiners regarding the caries detection method is essential. However, training and calibrating those examiners is an arduous task because it involves several patients who are examined many times. To facilitate this step, we aimed to propose a laboratory methodology to simulate the examinations performed to detect caries lesions using the International Caries Detection and Assessment System (ICDAS) in epidemiological surveys.

A benchmark examiner conducted all training sessions. A total of 67 exfoliated primary teeth, varying from sound to extensive cavitated, were set in seven arch models to simulate complete mouths in primary dentition. Sixteen examiners (graduate students) evaluated all surfaces of the teeth under illumination using buccal mirrors and ball-ended probe in two occasions, using only coronal primary caries scores of the ICDAS. As reference standard, two different examiners assessed the proximal surfaces by direct visual inspection, classifying them in sound, with non-cavitated or with cavitated lesions. After, teeth were sectioned in the bucco-lingual direction, and the examiners assessed the sections in stereomicroscope, classifying the occlusal and smooth surfaces according to lesion depth. Inter-examiner reproducibility was evaluated using weighted kappa. Sensitivities and specificities were calculated at two thresholds: all lesions and advanced lesions (cavitated lesions in proximal surfaces and lesions reaching the dentine in occlusal and smooth surfaces).

Regarding the reproducibility, the mean (range) of kappa values was 0.781 (0.529-0.927) for occlusal surfaces, 0.568 (0.191-0.881) for smooth surfaces, and 0.844 (0.698-0.971) for proximal surfaces. Considering all lesions, sensitivity and specificity mean values were respectively 0.724 and 0.844 for occlusal, 0.635 and 0.943 for smooth and 0.658 and 0.927 for proximal surfaces. For detecting advanced lesions, sensitivities and specificities were 0.563 and 0.920 for occlusal, 0.670 and 0.985 for smooth, and 0.838 and 0.985 for proximal surfaces.

The methodology purposed for training and calibration of several examiners designated for epidemiological surveys of dental caries in preschool children using the ICDAS is feasible, permitting the assessment of reliability and accuracy of the examiners previously to the survey's development.