| Objective To compare the changes of the Front smiling photographs of the skeletal Class ? malocclusion after the extraction and non-extraction,then to understand the related factors.Methods According to the inclusion criteria,18 cases of orthodontic patients with permanent dentition were selected as the study subjects: Their ages ranged from 12 to 29 years(18.55 ± 5.21 years old),78.06° ? SNA angle ?89.21°(82.49±5.04)°,76.93°?SNB angle? 85.21°(76.28±4.78)°,5°?ANB angle?9°(6.21±1.95)°,25°?SN-MP angle? 50°(36.70±6.89)°.According to the orthopaedic design method,there were 10 cases of extraction group,8 cases of non-extraction group,straight-wire technique,and the extraction group was all supported by the Micro Implant Anchorage,and 2 cases were combined with the Transpalatal arch.In the non-extraction group,2 cases were combined with the Micro Implant Anchorage,and 1 case was combined with the Facebow of a headger.Cephalometrics was used to measure the change of maxillofacial structure before and after treatment.Photoshop CS6 software was used to measure the positive smile before and after the treatment.SPSS22.0 statistical software carried out test of data before and after treatment.Pearson correlationanalysis was used to analyze the correlation between the structural changes of the soft and hard tissues and the changes of positive smile.Results Skeletal ? class malocclusion extraction correctional SNA,ANB,U1-NA,L1-NB,maxillary incisal display reduction,nasolabial Angle,width of smile,symmetry of smile,and the curvature of upper incisors increase;After the treatment of non-extraction,the SNB increased,But the ANB ?exposure of lower incisors decreased,and the difference before and after treatment was statistically significant(P < 0.05).Extraction and non-extraction changes in SNA,SNB,U1-NA,L1-NB,UL-E,LL-E,upper lip red thickness,smile width,and curvature of upper incisors were statistically significant(P <0.05).The changes of UL-E and upper lip thickness were positively correlated with extraction group.The changes of U1-NA were negatively correlated with the curvature of upper incisors and were negatively correlated with the changes in maxillary incisal display.The change of SN-MP was negatively correlated with the ratio of buccal corridor.There was a negative correlation between the changes of SN-MP and buccal corridor ratio before and after non-extraction treatment.Conclution 1.Skeletal ? class malocclusion extraction or not,the ANB were reduced,prompt sagittal relationship of upper and lower jaw can be improved after orthodontic masked treatment.2.After the treatments with Skeletal ? class malocclusion extraction and non-extraction,the improved degree of smile indicators is different between two groups,The possible reasons is that the degree of malocclusion and the severity of the problem of smiling beauty before treatment were different between the two groups;The effect of extraction on the red thickness and smile width of upper lip was greater than that of non-extraction group.It is suggested that toothextraction can affect the soft tissue morphology of the lips.3.Skeletal ? class malocclusion correctional U1-NA change were negatively correlated with the curvature of upper incisors and maxillary incisal display,suggest we should pay attention to front teeth root torque control during the process of adduction,avoid crowns tongue too much,Cause the curvature of upper incisors and the lower lip curvature are not consistent,then lead to an Adverse effect about the smile arc.4.After skeletal ? class malocclusion orthodontics treatment,the improvement of the positive smile besides associated with treatment design and method,the related muscle function training also have a positive role in improving the smile height,smile width,symmetry of smile. |
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