Mandibular Buccal Shelf Characteristics of South Indian Population with Different Skeletal Patterns- A Retrospective Cone Beam Computed Tomographic Study

Abstract

Introduction: The morphology of the Mandibular Buccal Shelf area (MBS) which is one of the ideal extra-alveolar locations for Mini-Implants (MI) may vary depending on the population and growth patterns. The success or failure of MIs placed in MBS could be affected by these morphological variations. Aim: The present study aimed to evaluate the angulation, bone width, and bone depth of the MBS area in South Indian population and the effect of age, gender, and skeletal patterns (both sagittal and vertical) on MBS dimensions using Cone Beam Computed Tomography (CBCT). Materials and Methods: This retrospective study was conducted at Saveetha Dental college, Chennai, from January 2022 to June 2022. Forty-five CBCTs of participants with various sagittal skeletal patterns were equally divided into three groups- Group-A: Class-I malocclusion; Group-B: Class-II malocclusion; and Group-C: Class-III malocclusion. Using the OSIRIX Lite software (version 12.0.3), the angulation, buccal bone width {4 and 6 mm from the Cementoenamel Junction (CEJ)} and buccal bone depth (6 and 11 mm from the CEJ) of the MBS were determined on CBCTs. The statistical analysis was performed by utilising SPSS software (version 23.0). Descriptive statistics were performed for all the parameters, Mann-Whitney U test was performed to compare the measurements in gender and each side of the arches, and the Kruskal-Wallis one-way analysis was performed to compare the measurements at different locations and different skeletal patterns. A p-value of <0.05 was considered statistically significant. Results: No significant difference was found between genders for the angulation, bone width and bone depth of the MBS (p-value>0.05). A significant difference in the angulation and width at 11 mm from the CEJ was noted between the age groups (p-value 0.01). The MBS posterior region had higher values for all parameters. Significant difference was noted for the different sagittal and vertical growth patterns (p-value <0.01) except bone width in vertical skeletal pattern. Conclusion: South Indian adults exhibited higher bone width in the MBS area. Sagittal skeletal Class-III subjects exhibited larger bone dimensions and hypodivergent patients reported greater apico-coronal bone depth than other growth patterns. The placement of MI in the MBS region must be done with caution considering the variations in different skeletal patterns.