Study On The Mechanism Of Action Of SUS~2 In Class ? Malocclusion

Objective:To evaluate the clinical efficacy of SUS2(Sabbagh Universal Spring 2)in the treatment of mandibular retraction of Class ? malocclusion in adolescents,and to evaluate the changes of mandibular and dental parameters before and after SUS2.Methods:21 patients(including 10 females,the average age of first diagnosis was 12.7 years old,11 males,the average age of first diagnosis was 11.4 years old)were selected from August 2015 to December 2018 in Shenyang City Stomatological Hospital.The patients were in growth and development.At the peak,the straight wire arch fixation appliance was used to align the dentition,and the SUS2 fixed function appliance was used to stimulate the mandibular development.The course of treatment was 6-8 months(average 6.8 months),and the cone beam was taken before and after treatment.CT(Cone Beam Computer Tomography,CBCT),three-dimensional reconstruction of mandible with Dolphin software and data measurement.Statistical data SPSS21.0 was used to measure the measurement data before and after treatment.Paired t-test was used to analyze P<0.05.Indicates a statistical difference.Results:In this study,patients with mandibular retraction of Class ? malocclusion in thegrowth and development period were treated with straight wire arch fixed appliance combined with SUS2 fixed functional correction,and received satisfactory clinical results in a short time.Changes in the upper anterior teeth: U1-NA(mm)decreased by 2.08 ± 0.31(mm),U1-NA(°)decreased by 3.81 ± 0.82(°),and U1-SN(°)decreased by 10.23 ± 1.60(°)),U1 cut-X axis(mm)increased by 1.55 ± 0.39(mm),U1 cut-Y axis(mm)decreased by2.09 ± 0.63(mm),U1 root-X axis(mm)increased by 1.14 ± 0.41(mm)U1 root-Y axis(mm)increased by 0.48±0.47(mm)on average,and the change was statistically significant.Changes in the lower anterior teeth: L1-NB(mm)increased by 1.89 ± 0.50(mm),L1-NB(°)increased by 5.02 ± 1.09(°),L1-MP(°)increased by 6.58 ± 2.28(°),the difference Statistically significant;L1 cut-X axis(mm)increased by 2.65 ± 0.93(mm),L1 cut-Y axis(mm)increased by 3.38 ± 0.88(mm),L1 root-X axis(mm)increased by1.82 ± 0.44(Mm),L1 root-Y axis(mm)increased by 0.56 ± 0.36(mm),the difference was statistically significant.Changes in the upper molars: U6-X-axis(mm)decreased by 2.88±0.75(mm),U6-Y-axis(mm)decreased by 1.62±0.38(mm),U6-X-axis(mm)decreased 1.15±0.32(mm),U6 root-Y axis(mm)decreased by 1.15±0.32(mm),the difference was statistically significant.The change of lower molars L6 occlusion-Y axis(mm)increased by 3.22±0.88(mm),L6 root-Y axis(mm)increased by 2.31±0.40(mm),the difference was statistically significant.Changes in the maxillary plane: OP-SN(°)increased by 2.80 ± 0.83(°),Gn-SN(°)increased by 3.04 ± 1.12(°),and the difference was statistically significant.;Maxillary changes: SNA(°),A-Y axis(mm)decreased,there was no statistical difference.Mandibular changes: SNB(°)increased by 3.60±0.59(°),ANB(°)decreased by3.00±0.59(°),SND(°)increased by 2.73±0.73(°),and BY axis(mm)increased by1.98±0.54(mm);Con-s-Go(mm)increased by 4.10±1.17(mm),Con-s-Po(mm)increased by 4.45±0.82(mm),the difference was statistically significant.Con-s-Po(mm)increased by 2.29±0.51(mm),but the growth of mandibular body was not statistically significant.Changes in the ankle: Po-NB(mm)increased by 0.15 ± 0.21(mm),the difference was statistically significant.Conclusion:SUS2 fixed function appliance is a functional appliance that can be used in combination with straight wire appliance.It can be used to make some changes in the mandible,and it can also make some changes in the teeth.The correction effect is a comprehensive The treatment outcome,the main change is the change in the mandible ascending branch.The SUS2 fixed-function appliance has a sustainable extension of the mandible and exerts an orthopedic effect,which can effectively promote the growth and development of the mandible of the mandibular retraction of Class ? malocclusion patients,thereby coordinating the positional relationship of the upper and lower jaws and the proportion of the face.Significantly improved patient occlusion and mandibular retraction:1.It can effectively improve the relationship between molars and the coverage of the anterior teeth;2.No significant effect on the growth and development of the maxilla;3,can effectively promote the growth and development of the mandible,improve the sagittal and vertical relationship of the upper and lower jaw;4.Promote the growth and development of the mandible mainly in stimulating the growth of the length of the mandibular ascending branch;5,the maxillary molars can be moved in the distance,the upper front teeth are inclined to the tongue,and the lower front teeth are inclined to the lips.