The Bone Thickness of Infrazygomatic Crest Was Measured on CBCTs

Assessment of Bone Thickness in the Infrazygomatic Crest and Proper Insertion Angle for Miniscrew Positioning: A Retrospective CBCT Study

This study will be done on 95 patients with CBCTs retrospectively, to evaluate the bone depth of infrazygomatic crest region for selecting suitable size of miniscrews and proper insertion angle clinical guide in the infrazygomatic crest without injuring the mesiobuccal root of the maxillary first molar.

CBCTs of 95 patients were collected retrospectively from archives of Faculty of Dentistry, Cairo University, that were requested for different dental purposes. The thickness of the IZC was measured above mesio-buccal root of upper 6 (U6MB), above disto-buccal root of upper 6 (U6DB) and contact point between upper 6 and 7 roots (U6-7). The distance from point of entry of miniscrew to the occlusal plane, that saves roots from injury, was measured. Then, the angle of miniscrew insertion in relation to the occlusal plane was measured at maximum thickness available together with point of entry in relation to the occlusal plane. The IZC thickness of right and left sides of each patient was compared, also compared in males and females. Kruskal-Wallis test, Paired Wilcoxon signed rank test & Spearman correlation were used to analyze results

Inclusion Criteria:

• Patients having full permanent dentition
• all cases were indicated for CBCT for their orthodontic treatment
• Patients with sound dentition

Exclusion Criteria:

• craniofacial anomalies and facial asymmetries
• Unclear CBCT
• mixed dentition
• Patients with systemic bone disorders