Abstract:

Abstract:Objective To analyze the feasibility of miniscrew placement in the buccal bone around maxillary molar roots for whole dentition distalization.Methods Pretreatment cone beam computed tomography (CBCT) images of 88 patients were evaluated,which were divided into two groups according to the number of the buccal root of maxillary second molars.The actual buccal bone thickness around the buccal roots of maxillary molars and bone thickness necessary for miniscrew placement there with the angle of 70° to the maxillary occlusal plane were measured.Upon comparison of the  two  sets data in each  group,the percentages of safety placement in patients were calculated.The interradicular space along the arch was measured for analysis of the available amount of distalization.Results In all the buccal areas there were certain percentages of patients could be inserted miniscrews safely.In the group of patients with two-buccal-root maxillary second molars,the highest safety rate of 85.70%,was around the mesiobuccal root of maxillary second molars;in the group of patients with single-buccal-root or fused root maxillary second molars,the highest safety rate of 91.38%,was around the maxillary second molar roots.The interradicular space along the arch in front of the mesial buccal roots was larger,and that in front of the distal buccal roots was smaller.Conclusion In all the buccal areas miniscrews can be inserted in certain patients,and the best buccal area is around maxillary second molar roots.Nevertheless,there isn’t an absolutely safe area.The application of dentition distalization by miniscrews in the buccal area of maxillary molar roots needs individual analysis.

Key words: miniscrew;maxilla,buccal;anchorage;dentition distalization