Diagnostic ability of computed tomography to evaluate external root resorption in vitro.

OBJECTIVES: The aim of this study was to evaluate the diagnostic ability of CT to detect simulated external root resorption defects. METHODS: External root resorption defects of different sizes and in different locations were simulated in 59 human mandibular incisors. Cavities simulating root resorption defects of 0.6 mm, 1.2 mm, or 1.8 mm in diameter and 0.3 mm, 0.6 mm, or 0.9 mm in depth (small, medium and large defects) were drilled in the cervical, middle and apical thirds of buccal surfaces. Axial CT was used to obtain cross-sectional images of the teeth, and 177 root thirds were assessed by a blinded observer. RESULTS: Of the 131 cavities, 117 were detected (89%). 32 of the 44 (72.72%) cavities located in the apical third were identified. A statistically significant difference (P<0.01) was found between the sizes of defects examined in the apical third. CONCLUSIONS: The evaluation of CT diagnostic ability revealed high sensitivity and excellent specificity. However, small cavities located in the apical third were more difficult to detect than all other cavities.