Effect Evalution And Invetigation On Rapid Expansion Union Molar Distalization

Crowding is the most common type of malocclusion,and the core of the correction is to obtain the space needed to relieve crowding.There are two ways to get the gap: one is tooth extraction,the other is non-extraction.If we only consider the arrangement of teeth and the occlusal relationship,we can solve the gap requirement use tooth extraction treatment for the vast majority of cases.But for some good soft tissue of young patients,in order to avoid the adverse effects of tooth extraction may have on the surface.The non-extraction is a choice.The commonly used methods of non-extraction treatments include Rapid expansion?molar distalization?interproximal enamel stripping and so on.Based on the physiological characteristics of maxillary tuberosity and molar space,Molar distalization has been accepted by most linical doctor.Using growth potential and opening the maxillary palatal arch to expansion is an another way to get space for crowding.The indications for the treatment of expanding arch on Mandible are limited,because only expansion of the maxillary arch makes it difficult to match the mandibular arch.With the development of Materials Science,A large number of patients with moderate to severe dentition crowding have been reported to have a good outcome by non-extraction treatments,however,most doctors are still skeptical about the stability and clinical efficacy of non-extraction techniques.At present,the study of non-extraction method is mainly focused on the change of dental arch shape and its influence on the lateral appearance and the amount and quantity of orthodontic therapy with coordination and long-term stability of the literature.Two non-extraction methods were studied in my reserach--Rapid expansion and molar distalization.Professor in our hospital XXX improved the design of a new type of mandibular spiral expansion device would be used in my reserech.Maxillary-Mandibular expansion union molar distalization were used to treat adolescent patients with moderate to severe dentition crowding.We will select the PAR index and HOWES index to observe the dental model before and after treatment and during maintain.In this way to verification the clinical efficacy and long-term stability of Maxillary-Mandibular expansion union molar distalization.To provide a reference for future clinicians to design orthodontic treatment,This thesis is composed of two parts:The clinical evaluation and stability of Maxillary-Mandibular expansion union molar distalizationResearch PurposesThe change of teeth and bone masss' coordination after Maxillary-Mandibular expansion union molar distalization treatment after treatment,and their clinical curative effect and long-term stability.Research MethodsSelection 51 adolescent patients cases with moderate crowding and both treated with Maxillary-Mandibular expansion union molar distalization treatment.There were 30 males and 21 females.Their model was measured before and after treatment and remained for more than four years.The Howes index and PAR index were used to measure the model before and after the treatment,and the data were analyzed by paired sample T test.Results1.In this study,the upper and lower jaw PMBAW/TM were(41.40±2.14)% and(41.53 ± 1.94)%both less than 44% before treatment.After treatment,the PMBAWU/TMU was(46.72±3.29)%,PMBAWL/TML was about(45.09±2.32)%,and the results before and after treatment were statistically significant.The results showed that at the end of the treatment,the samples of this study were obtained coordination of dental and bone mass.2.There was no significant change in PMBAWU/TMU from the end of treatment to the follow-up.The results showed that the treatment methods for maxillary expansion increases the width of the dental arch,the reconstruction of palatal suture is stability.3.The mandibular BALL/TML increased about(x=5.49 to p<0.001)after treatment,and there was no significant difference between the two groups.The increase of PMBAWL/TML was(x=3.55,p<0.001),and there was no significant change at the follow-up.For adolescent patients with mandibular arch expansion union molar distalization treatment for gap obtained is stable.4.After Orthodontic treatment,the PAR grade was improved,accounting for 78%,"significant improvement" accounted for 12%,no patient got“appearance variation or no change”.Conclusions1.After Maxillary-Mandibular expansion union molar distalization treatment,both adolescent patients with moderate crowding can get teeth and bone mass Coordination.The treatment produced more bone changes because of the method used the potential of growth and development,and its curative effect is stable.2.The modified mandibular spiral arch could vertical the lower dentition fasted.For the patients before treatment with PMBAWL/TML<44%,Maxillary-Mandibular expansion union molar distalization treatment is appropriate.