ASSESSMENT OF MANDIBULAR BUCCAL SHELF CHARACTERISTICS AS AN OPTIMAL SITE FOR MINI-SCREW INSERTION

Background: Orthodontic mini-screw implants have revolutionized anchorage strategies, offering enhanced control during complex tooth movements. The mandibular buccal shelf (MBS) is frequently favored for extra-alveolar mini-screw insertion due to its dense cortical bone and anatomical accessibility. However, most available anatomical data stem from non-South Asian populations, limiting direct application in the Pakistani context. Region-specific CBCT-based evidence is essential to ensure safe and effective mini-screw placement aligned with local anatomical patterns. Objective: To evaluate mandibular buccal shelf bone thickness and apicoronal depth at clinically relevant points across different vertical skeletal patterns in a Pakistani orthodontic cohort using three-dimensional CBCT imaging. Methods: This cross-sectional study was conducted at the Department of Orthodontics, Islamic International Dental College, Islamabad, from October 2024 to April 2025. A total of 78 orthodontic patients aged 13–30 years were included. High-resolution CBCT scans were analyzed to measure MBS bone depth at 4 mm and 6 mm apical to the cementoenamel junction (CEJ), and bone thickness at 6 mm and 11 mm below the CEJ, bilaterally. Vertical skeletal pattern was determined via mandibular-maxillary angle (MMA), categorized as low (<21°), normal (21–29°), or high (>29°). Data were statistically analyzed using ANOVA and independent t-tests. Results: The sample had a mean age of 22.67 ± 4.47 years and a mean BMI of 25.04 ± 1.02 kg/m²; 51.3% were male. At 4 mm from the CEJ, bone depth averaged 17.70 ± 1.95 mm (low angle), 17.42 ± 1.99 mm (normal), and 17.60 ± 1.89 mm (high). At 6 mm, depths were 12.30 ± 1.71 mm, 12.38 ± 1.94 mm, and 12.55 ± 1.79 mm, respectively. Bone thickness at 6 mm was approximately 4.67 ± 1.30 mm across groups, increasing to 5.55 ± 1.07 mm at 11 mm. No statistically significant differences were noted by skeletal pattern, gender, or hemiarch (p > 0.05). Conclusion: The MBS demonstrates consistent bone morphology suitable for mini-screw anchorage in Pakistani patients, regardless of vertical growth pattern or gender. CBCT remains essential for individualized treatment planning and minimizing complications.