Effect Of Different Extraction Model For Soft Tissue Profile Of The Angle â…¡~1 Malocclusion In Growth And Development Period

Objective: By comparing analysis before and after treatment X-ray radiographs of AngleⅡ1 patients in the growth and development period,.Comparison of changes in the soft tissue profile with mandibular extraction and non-extraction treatment,to investigate the effects of different extraction model for soft tissue profile,and provide reference for clinical treatment planning.Methods: From patients with ClassⅡdivision 1 malocclusion, between 2012 and2013 to Shenyang Stomatology Hospital Orthodontics for treatment, randomly selected 20 adolescents patients that have been treated end. The average age was 13.0±2.13 years old,with typical distal molar relationship,ANB angle greater than 5degrees,lower incisors with slight lip to tilt,the under arch with mild to moderate crowding.Where the extraction of two maxillary first premolars were 10 cases(five cases each for men and women), extraction of two maxillary first premolars and mandibular two second premolars 10 cases(five cases each for men and women).All patients were satisfied with the treatment outcome after treatment.Before and after treatment,using the American Dentsply ORTHORLIX, S-type panoramic X-ray machine,under strict head positioning locator,taken X-ray film.And X-ray Cephalometric were measured.Soft tissue analysis,combined Holdaway H analysis with Merrifieid Z angle analysis,finally adopted 12 soft tissue indicators. According to this study needs,hard tissue measurements adds angle of the lower incisors、mandibular plane angle and other four metrics. Analysis and comparison of soft tissue profile of two groups of patients before and after treatment,emphasis contrast difference between the two groups of patients before and after treatment with or without distinction,and observe the changes of the lower incisors and the mandibular plane angles change.The data were analyzed by SPSS19.0 statistical software, P <0.05 was considered statistically significant.Results: The two groups of patients after orthodontic treatment have been good Overbite and overjet relations of front teeth, Nasolabial chin and other soft tissue profile form coordination, face type improvements, teeth in order, occlusion coordination.Extraction of two maxillary first premolar group, Canine neutral relationship and Molar as far relations.Extraction of two maxillary first premolars and mandibular two second premolars group,Canine and Molar are neutral relationship.Two groups of patients after treatment, Nose protrusion of Soft tissue 、 U1-Si distance Were increased compared with that before treatment. Sn-Prn(mm) increased by 1.83± 1.73(P <0.01), 1.68±0.66(P <0.05), U1-UL(mm) increased by 1.48 ±1.54(P <0.05) and 2.52±0.97(P<0.05), and there were significant differences. Groove depth of the upper lip、Under the nose points to the H line distance、H angle, both decrease compared with that before treatment. Where Sn-Ls(mm) were reduced by 1.34 ± 1.42(P <0.05)、1.79 ± 1.95(P<0.05); Sn-H(mm) were reduced by 1.83 ± 2.25(P <0.05) and 2.04 ± 2.42(P <0.05); H angle(°) were reduced by 3.45 ± 3.39(P <0.05)、2.70 ± 1.16(P <0.05). The second group Analysis showed: A point to surface plane distance and Z angle,Higher than the pre-orthodontic treatment the differences were statistically significant. The index of representatives of L1-NB、L1-MP of two groups were no statistically significant change before and after treatment. However, the difference was significant difference between the T2-T1, P values were 0.042 and 0.038.In addition, the distance from point A to the surface plane, there were significant differences, the remaining difference was notstatistically significant.Conclusion:(1) AngleⅡ1 patients in the growth and development period,patients could get coordination relations of soft tissue with both extraction methods, face type improvement, occlusion coordination,teeth arranged in rows;(2) According to this study,between the two groups of patients before and after treatment showed no significant difference.There was no significant correlation between Soft tissue profile and mandibular extraction or non-extraction. Clinicians should select the appropriate extraction mode according to the patients overall conditions,to develop an personalized treatment plan,reduce the difficulty of treatment.