Early Clinical Intervention Methods And Efficacy Studies Of Anterior Crossbite

Anterior teeth crossbite is a common malocclusion in childhood.Its clinical manifestation is that the anterior teeth of children with central occlusion have a reverse jaw and overburden relationship.This kind of malocclusion may aggravate with the growth and development symptoms of children.It not only affects the normal development of oral function and facial beauty,but also seriously affects the mental health of children.Domestic scholars have investigated the prevalence of deciduous anterior teeth crossbite,and the prevalence rate is as high as 8.49%^[1].In order to avoid further aggravation of malformation and even to develop into severe skeletal malocclusion,most researchers believe that the treatment should be started as soon as possible with the cooperation of children^[2].The maxillofacial occlusal splint removable appliance is a kind of commonly used orthodontic method for the treatment of the anterior deciduous teeth crossbite.As a component of the appliance,occlusal splint is used to elevate the posterior teeth to remove the anterior teeth interlocking.However,the application of occlusal splint may affect oral hygiene,increase the number of visits,cause acute discomfort of patients and even cause pathological reconstruction of temporomandibular joint^[3-5].With the maturity of clinical technology and the development of relevant theory,the use of non-occlusal splint removable appliance in the treatment of children with maxillary anterior teeth with shallow overbite avoids the disadvantages of using occlusal splint,but there are few reports at home and abroad.Because of the vast area of China,limited by the different survey criteria,sample population,survey time and scope,most of the epidemiological surveys on malocclusion still have some limitations,which are not enough to represent the general situation of the whole population.Therefore,on the basis of the previous epidemiological investigation of malocclusion in deciduous dentition,this study intends to fill in the gaps in the data by investigating and analyzing the current epidemiological situation of malocclusion in mixed dentition children in Weinan area,and explore the clinical efficacy of non-occlusal splint removable orthodontics and traditional occlusal splint removable orthodontics in the treatment of maxillary anterior crossbite,and the related complications in the process of orthodontic treatment,so as to provide a new idea for the clinical treatment of anterior teeth with crossbite.Aim:1.To understand the epidemiological status of malocclusion in mixed dentition children in Weinan area through epidemiological investigation,to provide theoretical basis for early treatment of malocclusion.2.Through clinical randomized controlled trials,the clinical effects of maxillary removable appliance without occlusal splint and maxillary occlusal splint removable appliance in the treatment of maxillary anterior teeth were compared,and the possible mechanism of the relief of maxillary crossbite was discussed.3.By observing and analyzing the adverse conditions of children with deciduous anterior crossbite transect during treatment,to explore the possible causes,and to evaluate the application of different appliances through questionnaires.Methods:1.In the first part of the study,according to the principle of stratified random sampling,children in the dentition period in Weinan were selected to check their occlusion,and the data were statistically analyzed through questionnaires to investigate the risk factors associated with malocclusion.2.The second part of the study was based on the exclusion criteria of admission,and the deciduous children who were treated for anterior teeth crossbite were collected and divided into the experimental group and the control group according to the randomized method of the block.The experimental group used the maxillary activitor appliance without the occlusal splint.The treatment was performed,and the control group was treated with a maxillary occlusal splint activitor appliance.The time required from crossbite to the end of treatment was observed separately.The results were analyzed by group t-test.The cephalometric analysis was performed to analyze the lateral position of the skull before and after surgery.Using t-test to compare the therapeutic effects of the two appliances.3.The children in the second part of the study were routinely examined by oral examination,and the adverse conditions and related complications during the treatment were observed and recorded.After the treatment,the parents completed the questionnaire,from the treatment time,treatment experience,comfort Evaluation of the clinical effects of two appliances in terms of satisfaction.Results:1.According to the principle of stratified random sampling,707 children aged 6-12were selected from three primary schools in Weinan area.The prevalence of one or more malocclusions was 34.7%.The highest prevalence of deep overbite was 9.9%.Theincidence of anterior crossbite was 8.6%.The risk of malocclusion in children with bad oral habits was 2.2-6.6 times that of normal children.（P<0.001）.2.Sixty-six cases were collected according to inclusion and exclusion criteria,and three cases were withdrawn according to the test plan,which met the test requirements.Compared with maxillary occlusal splint removable appliance group,maxillary removable appliance without occlusal splint took more time to move the upper anterior teeth to theopposite edge（P<0.01）,but there was no significant difference in the total treatment time between the two groups（P>0.05）.The results of cephalometric measurements before and after operation showed that the main mechanism of anti-jaw relief in the two groups was lip movement of the upper anterior teeth.There was no significant difference between the two groups（P>0.05）.3.The main adverse conditions in the treatment of children are:bruxism,caries,sleep-disordered breathing,decay of the deciduous teeth,abnormal root resorption ofdeciduous molars,etc.Questionnaire results showed that the comfort degree,adaptation period and masticatory efficiency of appliances in the non-occlusal splint orthodonticgroup had obvious advantages（P<0.05）.Conclusion:1.The prevalence of malocclusion in children’s dentition period in Weinan is as high as 34.7%.The deep mandibular and anterior teeth are the main type of malocclusion.The occurrence of malocclusion in children’s dentition period is closely related to bad oral habits.2.The use of a maxillofacial maxillary active appliance for the treatment of the anterior teeth of the anterior teeth was not significantly different from the maxillary active appliance.3.The maxillary occlusal splint removable appliance has significant advantages in terms of wearing comfort,length of adaptation,chewing efficiency,and can be used as an option for the treatment of anterior teeth crossbite.