Bone thickness of mandibular buccal shelf for miniscrew insertion: literature review

Aim: the objectives of this systematic review were to analyze the buccal bone thickness and bone depth of the mandibular buccal shelf (MBS) to determine the most suitable sites for miniscrew insertion. Methods: electronic research was performed on PubMed database, using the PRISMA (Preferred Reporting Items for Systematic Reviews and meta-analysis) checklist. Keywords used were: “Buccal shelf AND miniscrew”. Articles from 2013 to 2023 have been considered. Results and conclusions: 20 articles were found and 13 articles, that met the inclusion and exclusion criteria of the review, were selected. 12 studies agreed that the site of the MBS with the optimal anatomic characteristics was the distal root of the second molar, and one study claims that it is not the ideal site. The three scan planes have been refocused. The axial view has been reoriented to pass through the bifurcation point of first and second molar. In the axial plane, two points were identified at the mesial root of the mandibular first molar and the distal root of the second molar to reorient the sagittal scan plane. The coronal plane was reoriented in the direction of the coronal two-thirds of the mesial and distal roots of the first and second molars. The thickness of the cortical bone of distal root of the second molar it was typically greater than 6 mm from the amelocement junction and where the ideal bone depth is it is located 4 mm from the amelocement junction. The thickness of the buccal bone is instead usually thinnest at the level of the distal root of the mandibular first molar. No statistically significant differences according to gender were found for the characteristics of the buccal shelf. Three studies analyzed the influence of the divergence on the bone thickness for mini-screws insertion, however the results aren’t in agreement with each other.