The Impact Of Extraction And Nonextraction Treatments On The Frontal Views Of The Soft Tissue

Objective: The purpose of this study was to research the impact of extraction andnonextraction treatments on the frontalviews of the soft tissue in Class I patients, and then todirecttheorthodontists todesign orthodontictreatmentplans.Methods: Dental arches and frontal view photographs of 30 extraction and 30nonextraction orthodontic patients with Class I malocclusions were measured with thesoft-ware Picasa 3 and e-ruler1.0 before and after orthodontic treatment. All the patients are10~18 years old. There wear 5factors to be measured on each patients'photographs: the archwidth, the buccal corridor, the number of exposed teeth when smiling, the width of relaxedoral fissure, and the correspondence thickness of the upper and lower relaxed lip vermilion.Paired t-test was used to evaluate the treatment changes within each group. Group t-test ofindependedsampleswasusedtocomparethechangesbetweengroups.Result: In the extraction group, after orthodontic treatment the maxillary anterior archwidth increased (P<0.05)and the maxillary and mandibular posterior arches'width decreased(P<0.05).Whilethe mandibular anteriorarch widthhadno significancechange (P>0.05).Inthe nonextraction group, after orthodontic treatment the arch width of neither the maxillarynorthe mandibular hadsignificancechange(P>0.05).In the nonextraction group,after orthodontictreatment the buccal corridor index decreased(P<0.05), while in the extraction group, there was no significance change after treatment(P>0.05).In boththeextraction andthe nonextraction groups, afterorthodontic treatmentthe numberof exposed maxillary teeth when smiling increased (P<0.05). But there was no significancedifferencebetweenthechangesofthetwogroups(P>0.05).Inboth theextractionand thenonextractiongroups,afterorthodontictreatment thewidthofrelaxed oral fissure increased (P<0.05). But there was nosignificance difference between thechangesofthetwogroups(P>0.05). In the extraction group, after orthodontic treatment the upper and lower relaxed lipvermilion thickness decreased (P<0.05), while in the nonextraction group there was nosignificancechangeaftertreatment (P>0.05).Conclusions: The extraction and nonextraction orthodontic treatments can induceabove-mentioned changes. We can conclude that the extraction treatment can give more significanceimpact on esthetics in dentistry. So the orthodontists should consider them when designingorthodontictreatmentplans.