Optimizing the Anatomical Location and Procedural Parameters for Miniscrew Placement in the Infrazygomatic Region- A CBCT Study.

Abstract

This study evaluates the integration of anatomical and procedural guidelines to develop realistic protocols for successful miniscrew insertion in the infrazygomatic crest (IZC) region, using CBCT measurements. A total of 720 measurements were collected from 30 adult patients, focusing on the upper first molar (U6) region. A grid system was created in the sagittal plane, including 12 reference points around the U6, with horizontal and vertical measurement points. A 12-mm virtual IZC miniscrew was inserted at each reference point, with the angle adjusted for 1 mm of sinus penetration and 5 mm of projection beyond the bone surface. Insertion success was defined as maintaining a minimum 0.5 mm safe distance from the roots, classified as system-compatible (SC), while root contact (RC), failure to achieve sinus penetration (SF), or sinus perforation (SP) exceeding 1 mm were classified as failures. No significant differences were found among the reference regions (p > 0.05). The 15 mm-U6MB region, with an insertion angle of 41.22°±8.67° apically and 12.36°±2.48° mesially, had the highest success rate of 55.0 %. The 15 mm-U6DB region, while aligning with the guidelines, had a higher incidence of root proximity (56.9 %). At the 17 mm region, sinus perforations exceeded 1 mm in 96.8 % of cases. The recommended placement height of 15 mm above the POP, with a 40° apical and 10° mesial angle at U6MB, offers the best balance of stability and safety, in line with literature guidelines. This study provides clinicians with evidence for effective miniscrew placement, ensuring stability while avoiding critical anatomical structures.