Comparison Of The Arch Expansion Efficiency In Adult Patients With Angle Class ? Between Invisalign And Angelalign

Objective:The clear aligner has been widely used because of its beauty,comfort and other advantages.The efficiency of tooth movement is related to the material properties of the appliance and the way of tooth movement.At present,the commonly used clear aligner in China are Invisalign and Angelalign.Dental arch stenosis is a common malocclusion.Using the clear aligner to expand the arch can improve the ugly buccal gallery and make the patients smile more full.The appliance covers the occlusal surface of the teeth and slightly depresses the posterior teeth during the expansion process,which can reduce the elongation of the tongue tip and avoid the backward rotation of the mandible.The purpose of this study was to compare the expansion efficiency in adult patients with Angle Class I during nonextraction orthodontic treatment between Invisalign and Angelalign.Intending to provide reference for the clear aligner treatment.MethodAccording to the inclusion criteria,72 patients who underwent clear aligner treatment in the Orthodontics Department of the First Affiliated Hospital of Zhengzhou University from September 2017 to December 2019 were selected.35 patients were treated with Invisalign and 37 patients were treated with Angelalign.Three-dimensional digital models of pre-treatment,planned treatment in software and post-treatment were collected.3-matic software was used to measure upper and lower arch widths at two different points:cusp tips and lingual gingival margins,buccal inclination posterior teeth.Calculate the expansion efficiency.A paired t-test was used to compare the difference between expansion planned on software and the post treatment measurements,and to compare the difference between the buccal inclination on software and the post treatment.An independent t-test was used to compare expansion efficiency of lingual gingival margins with cusp tips and the expansion efficiency of Invisalign with Angelalign.Result1.For Invisalign measurements,there was a statistically significant difference in upper arch between the final outcome and the plan expansion(P<0.05).The expansion efficiency of canine,first premolar,second premolar,first molar,and second molar at cusp tips were 85.5±15.8%?83.8±13.0%?80.6±10.6%?78.8±11.1%?73.5±11.8%,at lingual gingal margins were 67.7 ± 9.4%,65.6±10.3%,62.5±11.4%,58.1 ± 12.6%,53.8 ± 12.8%.The expansion efficiency gradually decreased from the mesial to the distal.There was a statistically significant difference in lower arch between the final outcome and the plan expansion(P<0.05).The expansion efficiency of canine,first premolar,second premolar,first molar,and second molar at cusp tips were 93.3±10.1%?90.3±8.7%?87.9±12.6%?87.2±10.1%?83.1 ± 14.2%,at lingual gingal margins were 66.8±8.7%?81.1±13.4%?80.1± 11.8%?71.8±14.1%?64.3±10.7%.The cups tips showed significantly more expansion efficiency than the lingual gingival margin in upper and lower arch.Buccal tipping was observed in all posterior teeth of maxillary and mandible in post-treatment.The buccal inclination of the posttreatment was more than the planned position in upper and lower arch(P<0.05)2.For Angelalign measurements,there was a statistically significant difference in upper arch between the final outcome and the plan expansion(P<0.05).The expansion efficiency of canine,first premolar,second premolar,first molar,and second molar at cusp tips were 82.6±16.3%?81.1 ± 10.2%?79.2±13.3%?75.5±11.0%?72.7±17.8%,,at palatal gingal margins were 66.6±9.7%?64.4±14.1%?61.2±15.2%?60.7±11.6%?54.5±15.2%.The expansion efficiency gradually decreased from the mesial to the distal.There was a statistically significant difference in lower arch between the final outcome and the plan expansion(P<0.05).The expansion efficiency of canine,first premolar,second premolar,first molar,and second molar at cusp tips were 94.6±13.1%?89.7±10.4%?88.2±14.2%?85.5±9.6%?81.3±12.3%,at palatal gingal margins were 66.2±13.0%?78.6±12.3%?75.4±9.5%?74.3±12.7%?67.1±18.3%.The cups tips showed significantly more expansion efficiency than the lingual gingival margin in upper and lower arch.Buccal tipping was observed in all posterior teeth of maxillary and mandible in post-treatment.The buccal inclination of the posttreatment was more than the planned position in upper and lower arch(P<0.05).3.For maxillary and the lower arch measurements,there was no significant difference in the expansion efficiency at cups tips and palatal gingival margin between Invisalign and Angelalign(P>0.05).There was also no significant difference in the expansion efficiency of the Angels of the Times(P>0.05).Conclusion1.Using Invisalign to expand the arch of adult patients with Angle Class ? can effectively expand the upper and lower arch.Using Angelalign to expand the arch of adult patients with Angle Class ? can effectively expand the upper and lower arch.There was no difference in the arch expansion efficiency between Invisalign and Angelalign.2.The efficiency of expansion with clear aligner for the upper arch of adult patients with Angle Class ? declined from the mesial to the distal.3.The expansion of arch with clear aligners in adult patients with Angel Class ?was mostly achieved by the buccal movement.