Optimal Buccal Site for Mini-Implant Placement on Attached Gingiva of Posterior Maxilla: A CBCT Study

This research aims to investigate the optimal buccal site on the attached gingiva of the posterior maxilla for mini-implant placement for anchorage purposes in orthodontics. In 23 female patients, mini-implants were implemented between the roots of the first molar and second premolar, in the maxilla, for anchorage purposes. A CBCT was acquired for diagnostic purposes, and intraoral scanning was performed. Using the digital model that was the result of combining the DICOM and STL files, the cortical bone thickness and density, as well as the trabecular bone density, were measured on three axial bone slices corresponding to the three defined height levels (lower, middle, upper) on the attached gingiva, in the interradicular area. Pearson and eta correlation tests were performed in order to investigate possible correlations between height in the attached gingiva, and the corresponding cortical bone thickness and density, as well as the corresponding trabecular bone density. The correlations regarding the height level in the attached gingiva were medium for the cortical bone thickness, and weak for the cortical bone density, while a strong correlation was found between the cortical bone thickness and density. The upper level of the attached gingiva, between the second premolar and the first molar in the maxilla, is the optimal site for mini-implant placement, as the cortical bone thickness and density are probably greater than in the lower and middle level.