Application Study Of Class â…¡ Devision 1 In Teens Treated By Maxillary Expansion In Conjunction With Mandibulary Expansion

Angle proposed that we can expand maxilla by opening palatal in1860 s.Subsequently,Hass and Hyrax were found as maxillary expansion device.Rapid palatal expansion in orthodontic technology has been widely used in clinical.Unlike maxillary palatal expansion joints,the growth of the endochondral bone make the mandible growing,jaw joint cartilage get together with bone tissue between 1 to 1.5 years after birth.Because of the restriction on anatomy, some scholars opposed the mandibular arch expansion by questioning its long-term stability.The proportion of extraction treatment potentially is increasing,bringing the problom of face promblom in orthodontic treatment.Angle Class II division 1 malocclusion in adolescent is frequently observed in orthodontic practice.Most patients exists the problom of mandibular retrusion.The extraction of the first premolar or the second premolar may result into discordant face especially for borderling cases,which is harmful for the development of face. Concerning on the development of face,we are studying the mothod of nonextraction,expecial the expansion of mandibular all the time.Sandstrom et. think that afer the extraction of maxillary,the width of the mandibular arch increases.We draw on the advantage anddisadvantage between Bihelix,Schwarz,Crozat,we improve the production the device of mandibular arch expansion.The Hyrax maxillary expansion and improved mandibular expansion device apply on the the adolescent patients.ObjectiveThe adolescent with angle class II division 1 malocclusion,whose position and growth of the maxillary are ordinary,are treated with maxillary expansion in conjunction with mandibular expansion.The profiles of solft tissue are analyzed before and after orthodontic treatment by Cephalomeric Radiography.Tooth arch is analyzed by measuerment of model.The experiment can present theory data for effective treatment of ange class II division 1 malscclusion cases in adolescent.we can value the change of the profiles of hard and solf tissue and the tooth arch width.MethodTwenty adolescent patients(twelve males and eight females) with class II division I malocclusion were chosen.They were treated with the technology by maxillary expansion in conjunction with mandibular expansion.Cephalometrics were taken before andafter treatment.The eleven soft tissue measurements and eighteen hard tissue measuremets are measured with DOLPHIN software.Arch width were measured in the3-shapr software.The result are analyed by the software of spss13.0.Result1.The profiles of SNB showed significant increases.The profiles of ANB,Wits,A-NPg showed significant decreases in sagittal direction.The profiles of ANS-ME,CO-GN showed significant increases,the profile of MP-FH showed significant decreases in vertical direction.2.The profiles of U1-NA(mm),U1-NA(°),U1-NS(°),Overjet showed significant decreases。The width of uper first molar increases 4.61 mm,the width of lower first mola increases 4.29 mm.The width of uper the second premolar increases 6.82 mm,the width of lower the second premolar increases 6.97 mm.3.In soft tissue,the profile of LL-E showed significant increases,the profiles of N’PG’,H angle,Pn-Sn showed significant increases.4.Maxillary expansion in conjunction with mandibular expansion can not only solve the congestion but also make U1-NS reducing,not make L1-MP increasing.Conclusion1. Maxillary expansion in conjunction with mandibular expansion for adolescent can ieffectively improve the positional relationship between sagittal jaw.There is no impact on the development of the maxilla,but afer bootiong shrinking jaw forward,lift lock of mandibular development,guide the normal development of the jaw.2. With the using of maxillary expansion in conjunction with mandibular expansion soft tissue surface type tends to balance,coordinate3. Becuasue of the increading dental arch,maxillary expansion in conjunction with mandibular expansion can be used in patients with narrow arch,whichi not only can provide clearance to relieve congestion,but also make the resumption of upright tilt inner lip anterior teeth.Maxillary expansion in conjunction with mandibular expansion did not make the lower front teeth compensatory pour lip,helping the long-term stability.