Curative Effect Of Early Treatment On Patients With Class ? Or Class ? Malocclusion

Background and Objective: Early treatment refers to the prevention,interruption,correction and guiding treatment to malocclusion and malocclusion trend and the etiology of maxillofacial malocclusion in children's growth stage.The class ? malocclusion patients whose main manifestation were mandibular lake of development and class ? malocclusion patients whose main manifestation were maxillary lake of development,were selected in this study.Ricketts analysis method is proposed by Dr.Ricketts.It mainly reveals the relationship among bones,teeth and soft tissue profile.This method can predict the direction and development of the face growth and can be used to formulate the orthodontic plans and predict the curative effect.Three parameters,namely SNA?SNB and ANB,in the Steiner analysis represents the relative relationship between maxillary to skull,mandible to skull and maxillary to mandible,respectively.The purpose of this study was to treat class ? malocclusion patients or class ? malocclusion patients who were in their peak of growth or before the peak of growth with Twin-Block appliance or maxillary protraction appliance,respectively.The real values before and treatment,and the true values and predicted values after treatment obtained from above analysis,were compared respectively to investigate the changes of maxillary,mandible,teeth and soft tissues profiles after treatment,thus to evaluate the effect of early treatment and to provide basis for clinical treatment.Methods: 75 cases of class ?(30 cases)and class ?(45 cases)malocclusion patients who were in their peak of growth or before the peak of growth registered in department of orthodontics,school and hospital of stomatology,Jilin University from 2010 to 2016,were selected in this study.A total of 31 parameters were measured with Ricketts analysis method,and SNA,SNB and ANB angles were also measured at the sametime,using X-ray cephalometric lateral films of all patients before and after treatment.The true values before and after the treatment were labeled as A0 and A2,and the predicted values according to a forecast of early treatment was labeled as A1.The value difference between A0 and A2 was marked as d1(d1=A2-A0).The value difference between A1 and A2 was marked as d2(d2=A2-A1).All datas were analyzed by Student's t-test to determine the statistical significance.Results: For Class ? malocclusion patients: 1.Compared with true values of osteofacial parameters before treatment: the SNB increased by 2.58 degrees,Xi-PM increased by 2.50mm(P<0.05)and ANB decreased by 2.71 degrees(P<0.001)after treatment.2.Compared with true values of dentofacial parameters before treatment: The molar relationship distance and anterior overjet reduced by 2.81 mm,3.68 mm(P<0.001);L1-OP,U1-APog(°)reduced by 1.89 mm and 7.35 °,respectively;L1-APog(mm)significantly increased 1.84mm(P<0.01)after treatment;Compared with the predicted values,the molar relationship distance,anterior overjet and U1-APog(°)reduce by 2.77 mm,3.80 mm,7.64°(P<0.001),respectively;L1-OP decreased by 1.64 mm,L1-APog(mm)increased by 1.84 mm(P<0.01);U1-APog(mm)decreased 1.82 mm(P<0.05)after treatment.3.Compared with soft tissue parameters before treatment: the Ls-TVL,Sm-TVL and Pos-TVL increased by 1.85 mm,2.12 mm and 2.89 mm(P<0.05)after treatment.For Class ? malocclusion patients: 1.Compared with true values of osteofacial parameters before treatment: SNA increased by 1.72 °,SNB decreased 2 °,ANS-Xi-Pm increased by 2.01 °,PP-FH increased by 1.99 °,FH-CFXi decreased by 2.06 °(P<0.05);NBa-Pt Gn decreased by 2.78 °,FH-NA increased by 2.17 °,ANB increased by 3.71 °(P<0.01);A-NPog increased by 3.20 mm(P<0.001)after treatment.Compared with the predicted values,NBa-Pt Gn decreased by 2.77 °,PP-FH increased by 1.78 °(P<0.05),A-NPog increased 3.20 mm(P<0.001)after treatment.2.Compared with true values of dentofacial parameters before treatment: Themolar relationship distance,anterior overjet and anterior overbite increased by 3.23 mm,6.38 mm,4.75 mm,respectively.PTV-U1 increased by 3.38 mm,U1-APog(°),U1-APog(mm)increased by 11.13 ° and 4.31 mm respectively.L1-APog(°),L1-APog(mm)reduced by 4.80 ° and 2.02 mm(P<0.001)after treatment;Compared with the predicted values,molar relationship distance,anterior overjet and anterior overbite increased by 3.40 mm,6.29 mm and 4.53 mm,U1-APog(°),U1-APog(mm)increased by 10.77 ° and 4.19 mm,respectively.L1-APog(°)and L1-APog(mm)decreased 4.59 ° and 2.08 mm(P<0.001),respectively;PTV-U1 increased 2.05 mm,U1-L1 decreased 6.21 °(P<0.05)after treatment.3.Compared with soft tissue parameters before treatment: ANS-Em increased by 1.73 mm(P<0.01)and Em-OP decreased by 1.47 mm(P<0.05),Ls-TVL?Sm-TVL?Pos-TVL was decreased by 2.1 mm(P<0.001)?3.22 mm(P<0.001)?4.72 mm(P<0.001),respectively,after treatment.Conclusion: 1.Early application of Twin-Block appliance in treating class ? malocclusion patients during their growth period can make full use of the potential of growth,effectively promote the growth and development of mandible,improve the molar relationship,improve the anterior overjet,slightly adduct upper anterior teeth,improve labial inclination of upper anterior teeth,improve the soft tissue profile and thus simplify the second phase of fixed orthodontic treatment.Besides,patients are comfortable while treated with Twin-Block appliance with high compliance.Therefore,it is worth popularizing the early application of Twin-Block appliance.2.Early application of protraction appliance in treating class ? malocclusion patients during their growth period can make full use of the potential of growth,effectively promote the growth and development of maxillae,inhibit the excessive forward growth of mandible,improve the molars relationship,relieve the cross overbite and cross overjet of anterior teeth,improve the soft tissue profile greatly.