Comparison of mandibular buccal shelf morphology between adolescents and adults with different vertical patterns using CBCT.

Objective: This retrospective study aimed to analyze the anatomical structure of the mandibular buccal shelf (MBS) in adolescents and adults with different vertical patterns to determine the optimal location for miniscrew insertion in orthodontic treatment.

Methods: Cone-beam computed tomography (CBCT) scans of 230 patients were utilized for measurements. The morphology and thickness of alveolar bone at the MBS were measured. Two-way ANOVA and regression analysis were conducted to analyze the influencing factors on alveolar bone and cortical bone thickness.

Results: Age had a significant effect on alveolar bone thickness (level I: F = 62.449, level II: F = 18.86, p < 0.001), cortical bone thickness (level II: F = 18.86, p < 0.001), alveolar bone tilt (F = 6.267, p = 0.013), and second molar tilt (F = 6.693, p = 0.01). Different vertical patterns also influenced alveolar bone thickness (level I: F = 20.950, level II: F = 28.470, p < 0.001), cortical bone thickness (level I: F = 23.911, level II: F = 23.370, p < 0.001), and alveolar bone tilt (F = 27.046, p < 0.001). As age increased, the alveolar bone thickness at level I decreased by 0.096 mm and at level II decreased by 0.073 mm. Conversely, the thickness of alveolar bone at level I and level II increased by 0.06 mm and 0.075 mm, respectively. The cortical bone thickness at level I and level II increased by 0.024 mm and 0.29 mm, respectively. However, the alveolar bone thickness decreased by 0.931 mm and 1.545 mm at level I and level II, and the cortical bone thickness decreased by 0.542 mm and 0.640 mm at level I and level II, respectively.

Conclusion: Age, different vertical patterns, alveolar bone inclination, and different shapes of MBS significantly affected the thickness of alveolar bone and cortical bone in the MBS area. Notably, only alveolar bone thickness and cortical bone thickness at level II were affected by age and different vertical patterns simultaneously. These findings can provide valuable insights for orthodontic practitioners in selecting the most suitable location for miniscrew insertion during treatment planning.