Analysis On The Efficiency Of Arch Expansion And Its Influencing Factors With Clear Aligner

Objective: To analyze the efficiency of dental arch expansion and its influencing factors with clear aligner.Methods: The present study included 31 cases(7 males,24 females),mean age(31.8±8.8)years with Invisalign from the Department of Orthodontics,Fifth Hospital of Xinjiang Medical University.The 3D models of pretreatment,designed and posttreatment were collected,measure dental arch width of digital model and calculate the actual amount arch expansion by using the Geomagic Studio 2013 software.Compared with the ClinCheck provide and calculate the efficiency of the arch expansion.And evaluate the efficiency of the arch expansion,analysis its influencing factors.Results: The arch width could be extended with clear aligners.The actual expanding amount is obviously not enough to design expanding amount.From high to low,the arch expansion efficiency of maxillary first premolar(72.5±24.6)%,maxillary second premolar(70.4±26.3)%,maxillary canine(67.3±24.3)%,maxillary first molar(60.1±27.5)%,maxillary second molar(54.0±23.1)%,respectively.Arch expansion efficiency of mandibular first premolar(73.0±21.2)%,mandibular second premolar(72.7±26.1)%,mandibular canine(68.2±27.4)%,mandibular first molar(67.5±22.4)%,mandibular second molar(55.7±28.0)%,respectively,and the efficiency is medium.The actual buccal inclination changed more than the designed buccal inclination,and the posterior teeth were more buccal inclination.The total number of attachments,the design of attachments for molars or premolars had no significant effect on the expansion efficiency of maxillary or mandibular arch.The design of arch expansion and tooth movement pattern will affect the arch expansion efficiency.Conclusion: The clear aligners can expand the arch width effectively and the efficiency is medium.There is a difference between the designed and actual expansion,so it needs to be overcorrected.In order to achieve the overall buccal movement of the teeth,an additional buccal root torque is required.