Measuring Buccolingual Inclination of Mandibular Canines and Molars Using CBCT

Objectives:(1)To develop a reliable method to measure buccolingual inclination of mandibular canines and first molars; (2)To evaluate a possible correlation between canine and molar buccolingual inclination with their respective interdental width, and (3)To describe such inclinations for an untreated sample of pre-orthodontic patients. Methods: The study sample consisted of 37 male and 41 female untreated orthodontic patients, with an average age of 13.2±0.96 years. A line tangent to the inferior border of the mandible and the long axis of the tooth was used to measure buccolingual inclination. Intercanine and intermolar widths were measured on the study models using a digital caliper. Results: Reliability intraclass correlation values were greater than 0.94. The mean mandibular canine inclination was 98.0±4.1° with mean intercanine width of 26.0±2.2 mm. For the mandibular molars, the mean inclination was 74.6±4.7° and the mean intermolar width 40.9±2.7 mm. The first molar inclination of subjects with Class II molar (75.7±4.9°) was significantly less (p<=.05) than that of Class I subjects (73.5±3.7°). Low correlations were found when comparing interdental width and buccolingual inclination. Conclusions: CBCT can be used to reliably measure mandibular buccolingual inclination of canines and first molars. Dental compensations in molar inclination were seen for Class II subjects.