The Comparative Study On The Palatal Morphology Of Children In The Mixed Dentition Between Normal Occlusion And Angle Class Ⅱ Division 1 Malocclusion

The quantitative and qualitative study of craniofacial morphology is very important to the diagnosis and treatment of malocclusion. It's also useful for making right treatment plans.The palatal growth is a dynamic process involving length, width , height and time. There are several studies regarding palatal dimension assessment. Most have focused on craniofacial syndromes and cleft lip and palate. Such investigations have not produced a consistent view of the values for palatal dimension in healthy children. So the aim of our study are the follows:â‘ To provide a set of normative data related to the palatal growth and development of children in mixed dentition free from oral parafunctions and without respiratory problems. It will be helpful to the diagnosis of facial dysmorphology and the determination of the effect of therapy.â‘¡To compare the three-dimensional differences of palatal morphology between Angle classâ…¡division 1 malocclusion and normal occlusion. It will be helpful to the therapy. In the present investigation, the dental casts of healthy children were used to analyze the growth and development of the palate. In this study, grating projection system 3DSS-STD-II was used to reconstruct three-dimensional dental casts. This system has fast scanner speed, high precision, automatic landmarks splicing and the data can be directly input into the Geomagic to be mearured.Our study has two parts:1. the study on the palatal morphology of children in the mixed dentition with normal occlusion.Eighty-seven dental casts were obtained from children between 6 and 12 years of age (41 boys, 46 girls) with a normal mixed dentition. The children who were all han people were selected by a screening done in Xi'an, China. A grating projection system 3DSS-STD-II was used to reconstruct three-dimensional dental casts. The data can be directly input into the Geomagic to be measured. Then the palatal curve fitting was made in Matlab7.0 to directly show the palatal morphology. From the study, we can know that In the normal mixed dentition, there are no obvious changes in the anterior part of palatal vault. But the posterior part of palatal vault becomes higher .The reason is maybe that the growth rate of alveolar crest is different in the region of anterior teeth and posterior teeth.2. the comparative study of palatal morphology of normal children and Angle classâ…¡division 1 malocclusion patients.Twenty-two dental casts (14 boys, 8 girls) were selected from patients in Department of orthodontics, Stomatological hospital, Fourth Military Medical University. The method is the same as study one. From this study, we know that compared with normal occlusion, the palatal vaults of patients are more flat. This is maybe resulted from the retruded tongue which is caused by the retruded mandible. So, In clinical practice, using functional appliances to protrude the mandible maybe a good method to correct the palatal morphology of patients with Angle classâ…¡division 1 malocclusion.