Evaluating Maxillary Buccal Posterior Cortical Bone Thickness: A CBCT Study of Average and Vertical Growth Patterns in Orthodontics

Abstract

Introduction: Orthodontic skeletal anchorage enables the clinician to proceed with absolute anchorage during treatment. Cortical bone thickness is considered a determinant factor for the primary stability of TADs. Vertical facial morphology is important for the orthodontist, since it affects the goals and the approach of orthodontic treatment by having an effect on the growth & anchorage system also.  The purpose of this study was to assess and compare the cortical bone thickness in the maxillary buccal posterior region in average and vertical growth pattern subjects for orthodontic implants.

Objectives: To measure and compare cortical bone thickness between 4&5, 5&6, 6&7 regions in subjects with average and vertical growth patterns. To measure bone thickness at 12mm, 14mm & 16mm at angle of 45°,60°,70° & 80° for each height from maxillary occlusal plane as reference line. To investigate cortical bone thickness differences between right and left sides.

Methods: A total of 60 subjects were selected for CBCT images. 30 subjects in group A- Average Growth pattern (14 males and 16 females) & 30 subjects in group B- Vertical Growth pattern (14 males and 16 females). CBCT scans of the maxilla were taken in a VATECH machine. For all scans, the standard protocol was 95 kV, 8 mA, 12 × 10 cm field of view, 0.30 mm voxel size, and scanning time of 11-17 seconds. The CBCT images were analyzed using CS imaging software & bone thickness was measured in the maxillary buccal posterior region. Data were collected and analyzed using independent t test, Shapiro Wilk test, One-way ANOVA test, and Bonferroni post-hoc test.

Results: Both group A and group B showed significant differences on comparing inter-radicular cortical bone thickness between 4&5, 5&6, and 6&7 regions at different heights and different angles, between 5 & 6region had the maximum thickness followed by 6 & 7 region and then 4 & 5 region and group A showed greater values than group B from maxillary occlusal plane.

Conclusions: The desirable site for orthodontic TADs placement, stability & success rate may be between the 2nd premolar & 1st molar then 1st molar & 2nd molar, and 1st premolar & 2nd premolar respectively from maxillary occlusal plane.