Abstract
BACKGROUND: To evaluate, through cone-beam computed tomography (CBCT), the anatomical characteristics of the mandibular buccal shelf according to sex, facial biotype, hemiarch, and reference root, in order to determine bone availability for orthodontic mini-implant placement. MATERIAL AND METHODS: A cross-sectional observational study was conducted on 60 CBCT scans (480 roots) of patients aged 12-53 years. Measurements of angulation, horizontal bone thickness (4 mm and 6 mm), and vertical bone height (6 mm and 11 mm) were obtained at the mesial and distal roots of the mandibular first and second molars. Statistical analyses included t-test and one-way ANOVA (p < 0.05). RESULTS: The distal root of the mandibular second molar exhibited the highest bone dimensions (angulation 37°, horizontal thickness 17.3 mm at 4 mm and 10.0 mm at 6 mm, vertical height 5.4 mm at 6 mm and 6.7 mm at 11 mm), establishing it as the most favorable insertion site. In contrast, the mesial root of the first molar showed the lowest values. Sex-related analysis revealed slightly greater dimensions in males, with significant differences in horizontal thickness at 4 mm and vertical height at 11 mm (p = 0.05). No statistically significant differences were observed among facial biotypes or between hemiarches, although brachyfacial patients consistently showed the highest averages. CONCLUSIONS: The distal root of the mandibular second molar represents the most reliable anatomical site for mini-implant placement in the buccal shelf, regardless of sex or facial growth pattern. CBCT assessment remains essential for individualized planning and to minimize complications.