Bone availability in the sagittal dimension of the infrazygomatic crest for miniscrew insertion: A retrospective cone-beam computed tomography study

Background: There is limited information available regarding the bone volume in the sagittal dimension of the infrazygomatic crest (IZC) that is safe for the insertion of a temporary skeletal anchorage device. The objective of this study was to assess the sagittal bone availability when the anterior and posterior walls of the IZC reach an inclination of 45°. Methods: A cross-sectional investigation was undertaken on 100 cone-beam computed tomography scans of 40 males and 60 females. A total of 20 landmarks were digitized for each IZC outline, 1 mm from the vestibular alveolar bone, and their x, y, and z coordinates were extracted. Afterward, the sagittal measurement of the IZC at which the curvature reached 45° was recorded. Symmetry of measurements was assessed using paired-samples t tests. In addition, these measurements were compared as a function of sex and age group (≤21 vs >21 years) using an independent-samples t test and the Spearman rank correlation coefficient test (P <0.05). Results: There were no significant differences between paired sagittal measurements of the IZC (3.5 ± 1.5 mm on the right side and 3.6 ± 1.3 mm on the left side; P = 0.144), except for younger patients (P = 0.030). In addition, no significant differences were found between corresponding male and female measurements (P ≥0.149). A significant discrepancy was identified between the younger age group (3.2 ± 1.2 mm) and the older cohort (3.8 ± 1.6 mm) for the sagittal dimension of the right IZC (P = 0.038), with an estimated mean difference of 0.03-1.16 mm (95% confidence interval). A significant positive weak correlation was found between the sagittal dimension of the right IZC and age (ρ = 0.201; P = 0.045). Conclusions: Sufficient IZC bone volume is An angle of 45° for inserting a temporary skeletal anchorage device, with no sex or side variation, except for the significantly greater sagittal dimension of the right IZC in older patients.