Occlusal caries extension in relation to visual and radiographic diagnostic criteria: Results from a microcomputed tomography study

Abstract

Objective: This in vitro study aimed to evaluate occlusal caries extension in relation to visual and radiographic diagnostic criteria and their clinical value to indicate operative or preventive dental care. Methods: A total of 196 third molars with clinically sound occlusal fissures or noncavitated lesions were collected. Before microcomputed tomography (μCT) investigation, each tooth was examined visually and radiographically. Kühnisch's μCT-based caries-extension index (CE index) was used to determine the caries depth on a numeric scale (0=sound; 0.01-0.99=enamel caries; 1.0-1.99=dentin caries). Sensitivities (SEs), specificities (SPs), and area under the receiver operating characteristic curve (Az value) were also calculated. Results: Based on μCT data, the following mean CE index values and standard deviations (SDs) were documented according to the visual criteria: sound=0.6 (0.4); first visible signs=0.9 (0.4); established lesions=1.3 (0.3); microcavities=1.4 (0.2); dentin exposure=1.5 (0.2); and large cavities=1.5 (0.3). The radiographic categories according to Marthaler (enamel caries [D0-2], caries in the outer half of dentin [D3], and caries in the inner half of dentin [D4]) were related to CE index values of 0.9 (0.4), 1.4 (0.2) and 1.6 (0.4), respectively. Caries detected visually or radiographically showed an SE of 84%and an SP of 85%(Az=0.85). When both methods were used to predict dentin involvement simultaneously, SE=27%, SP=100%, and Az=0.63; this combined visual and radiographic approach was associated with a perfect specificity and no false-negative decisions. The proportion of false-positive diagnoses was moderately high, and lesion extension in these cases was mainly limited to the outer 20%of the dentin. Conclusions: Our results might be useful for differentiating between preventive and operative dental care for pits and fissures.