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Objective: To evaluate infrazygomatic bone thickness for safe placement of infrazygomatic implant using CBCT.
Methods: This retrospective cross-sectional study was conducted in Orthodontics department of Khyber College of Dentistry, Peshawar. Computed tomographic records of 116 patients were taken to assess bone thickness in the coronal view. Measurements were made along the distobuccal root of 1st molar at angles ranging from 55° to 75° to maxillary occlusal plane and a line tangent to distobuccal root of 1st molar. Data was represented as tables and figures. Independent samples t test was employed to see the relation of the insertion angles and mean height from occlusal plane with gender.
Results: Bone thickness at infrazygomatic crest region varied at different insertion angles. Bone thickness at insertion angles of 55° to 75° ranged from 3.07 ± 0.94mm to 4.91 ± 1.59mm to maxillary occlusal plane. This value increased with increasing insertion angles. The height from occlusal plane also varied with higher values at small insertion angle i.e., 18.5mm at 55° and smaller values at high insertion angle i.e., 16.02mm at 75°. There was a significant difference in insertion heights from occlusal plane at insertion angles of 60°-75° according to gender, with higher insertion position in males (p value <0.05).
Conclusions: For minimum bone support of 3mm at infrazygomatic bone crest & safe placement of screw without injuring distobuccal root, the miniscrew should be inserted at an angle of 55° to 70° at distances of 16mm to 18mm from maxillary occlusal plan.