The Maxillary Dentition Width Variation Of Space Closure With Sliding Mechanics With TPA:a 3D Finite Element Analysis

Objective: To clarify the influence of the TPA on the transverse movement of the upper posterior teeth in the course of space closure with sliding mechanics.Materials and methods: The CBCT data of a male patient who had maxillary first premolars extracted was imported into the Mimics software for 3D reconstruction.Six loading conditions of the amount of space closure respectively 0,2,4 mm with or without TPA were calculated in ANSYS software to analyze the transverse initial displacement of maxillary canine,the second premolar,the first molar and second molar.Result:The transverse movement type of the canine,the second premolar and the first molar were all lingual crown tipping,by contrast,the second molar was buccal crown tipping at different stages of space closure with or without TPA;the dispalcement of lingual crown tipping of the canine,the second premolar,and the first molar in TPA group were smaller than the control group,the average decrease by 14.8%,14.8% and 29.7% respectively.Buccal crown tipping of the second molar was increased by 48.2% on average.Conclusion:During the space closure with sliding mechanics,the use of TPA was beneficial to the stability of the upper arch,but which could increased buccal crown tipping of the second molar should be noticed.