Occlusal caries diagnosis in molar teeth from bitewing and panoramic radiographs

Previous studies have implied that the panoramic radiograph was inferior to the bitewing radiograph for caries diagnosis. However, these clinical studies lacked a method of validation. The aim of this study was to use an electronic caries meter (ECM II, LODE, Groningen, The Netherlands) to validate occlusal caries diagnosis made from bitewing and panoramic radiographs.

Forty-nine Army recruits were examined with the ECM, and had bitewing and panoramic radiographs taken. In total 299 molar occlusal surfaces were available for examination. Seven examiners viewed the bitewing and panoramic radiographs on two separate occasions and assessed each occlusal surface for dentine caries as 1: almost definitely no caries, 2: probably no caries, 3: unsure, 4: caries probably present, and 5: caries almost definitely present. This was repeated on 20% of the radiographs at two further separate sittings. ECM conductance readings greater than 9 were taken to indicate dentine caries. Examiner decisions that caries was probably and definitely considered to be present were taken as positive diagnoses.

Bitewing and panoramic radiographs provided sensitivity values of 0.25 and 0.19 and specificity values of 0.93 and 0.97 respectively. ROC analysis indicated no statistically significant difference in diagnostic quality between the bitewing and panoramic radiographs. Intra-examiner reproducibility was found to be poor to moderate (Kappa values for bitewing = 0.31-0.44, panoramic = 0.07-0.54).

No difference in overall diagnostic performance was found between bitewing and panoramic radiographs for the diagnosis of occlusal dentine caries.