A Controlled Clinical Study Of The Soft Tissue Profile Improvement Treated By Surgery-first Approach Of Mandibular Prognathism And Normal Population

Objcetive:Based on the surgery first approach,bilateral sagittal split ramus osteotomy has become a feasible treatment to treat the Mandibular Prognathism and the correction of’ the teeth after the operation.In this paper,the improvement of the soft tissue profile in the treatment process of the Mandibular Prognathism is evaluated objectively by comparing with that of the normal population.Our conclusions can provide reference to formulate clinical plan.Methods:20 patients(8 male and 12 female)with adult mandibular prognathism were collected as treatment group,who were treated by surgery first approach for Skeletal Class III in the Department of Maxillofacial Plastic Surgery,oral orthodontic center of Plastic Surgery Hospital Chinese Academy of Medical Sciences from January 2011 to June 2017.We analyzed their X-ray cephalometric in preoperative(TO),postoperative week(T1).postoperative six months(T2),measured the data of their the soft tissue profile and anatomic landmark.20 patients(10 male and 10 female)with not malocclusion,the soft tissue profile,nosc and chin deformity were collected as control group,who filmed an X-ray cephalometric during their visiting in Plastic Surgery Hospital,Chinese Academy of Medical Sciences between January 2014 and December 2017.We measured the same data as the treatment group to make Statistical analysis.By comparing the relationship of the soft tissue profile data between the treatment group and the control group during T0,T1 and T2,we can come to a conclusion that the"surgery first approach" treatment of the Mandibular Prognathism deformity could show the characteristics of the soft tissue profile malformation quickly,and showed the satisfactory effect in the early stage of treatment.Results:1 patient suffered open bite phenomenon after the mandibular sagittal split up operation a week later,which incidence was 5%.Open bite phenomenon has been solved through elastic force without other complications.Postoperative soft tissue profile changes as follows(mean value):1)The improvement of lateral facial angle:compared with the control group’s ’T0 and T1,the total angle was improved by 6.30(66.3%),the nose and lip angle was 1.9°(41.3%);the mental lip groove angle was improved by 14.7 °(89.3%),and the T2 was further improved by 0.3°than that of the T0.2)Soft tissue mark-direction change:The LL-Y axis improved 5.5mm(127.9%)by comparing T1 with T0,T2 was further 0.2mm compared with T1,the Si-Y axis improved 7.8mm(104%)by comparing T1 with TO,T2 was further 0.2mm compared with T1.The pos-y-axis improved 7.9 mm(97.5%)by comparing T1 with T0,T2 was further 0.2 mm compared with T1.The Mes-Y axis improved 7.5 mm(89.3%)by comparing T1 with T0,T2 was further 0.2mm compared with T1.3)The relationship between soft tissue markers and esthetic plane:compared with the control group’s TO and T1,Sn-E plane was improved 1.9mm(100.0%),UL-E plane was improved 3.6 mm(94.7%),LL-E plane was imporved 0.5mm(100.0%),and Si-E plane was improved 1.0 mm(85.1%).4)The recurrence:①compared with the control group’s T1 and T2 the recurrence of the total angle was 0.4 and the nasal labial angle was 0.5;②compared with the control group’s T1 and T2,the Sn-E line recurred 0.2mm,the UL-E line recurred 0.8mm,and the LL-E plane recurred 0.8mm;③The soft tissue marker point sagittal change did not relapse.Conclusion:The " surgery first approach " model was used to treat the Mandibular Prognathism malformation at one week after the operation(T1).The dissection points of the soft tissue profile were significantly shifted and the relationship with the aesthetic level changed into coordination.The measurement and statistical analysis showed that the one week(T1)was greatly improved by comparing with the preoperative(TO),and the rate of improvement of most markers could reach about 90%.At half year of operation(T2),most sign points of the side appearance and the aesthetic level were recurrence compared with T1(most of the P>0.05),which did not show regular pattern.The soft tissue side appearance did not show obvious relapse tendency in the six months after "operation priority".In the treatment of Mandibular Prognathism,the characteristics of the malformation of the soft tissue profile were improved rapidly,and it showed a good effect in the early stage of-treatment and avoided the "ugly duckling" deformity of the face caused by orthodontic before operation.