The Analysis Of Dental And Basal Bone Arch Form Matching In Skeletal Class Ⅱ Malocclusion

Objective: In this study,we established the mathematical models describing the dental and basal bone arch form of skeletal Class Ⅱ malocclusion,and did the related matching study about them.At the same time,we completed writing computer software program containing the process from 3D data processing to function model generating in this experiment,in order to provide digital basis for diagnosis and treatment design of the clinical cases.Methods: 1.We selected 30 patients of skeletal class Ⅱmalocclusion(AngleⅡ1 malocclusion)(19 females,ages of 21.84±5.14;11 males,ages of 20.90±3.85)as the experimental group,and 30 individual normal occlusion patients(17 females,ages of 20.24±5.66;13 males,ages of 21.62±3.93)as a control group,which were both captured images by CBCT in Tianjin Stomatological Hospital Orthodontic Department from September 2014 to January 2017.2.We processed the CBCT data through Invivo5.4 software,to gain 3D data acquisition of marking points of dental and basal bone arch.Then the computing program was written on the Eclipse development platform by Java language,which was preset for the data processing target in this study.Then Beta-function was used to establish the mathematical models describing the dental and basal bone arch form of skeletal ClassⅡmalocclusion with the characteristic data calculated by the equations.3.We use SPSS 17.0 statistical software for testing the fitting correlation between beta function and dental or basal bone archform curve,and did the matching analysis and research about them.Results: 1.The mathematical model describing the dental arch form of skeletal Class Ⅱ malocclusion was established.Maxillary: Y=41.01[ 1-(2X/61.08)2 ]0.73 Mandibular: Y=37.35[ 1-(2X/59.55)2 ]0.717 2.The mathematical model describing the basal bone arch form of skeletal Class Ⅱ malocclusion was established.Maxillary: Y=29.15[ 1-(2X/65.63)2 ]0.721 Mandibular: Y=30.91[ 1-(2X/79.19)2 ]1.242 3.The dental arch and basal bone arch forms in maxilla and mandible are highly correlated fitting with Beta function.4.The dental arch depth of skeletal Class Ⅱ malocclusion both in upper and lower jaw are larger than the individual normal occlusion,the difference was statistically significant.5.The basal bone arch width of skeletal Class Ⅱ malocclusion in lower jaw is less than individual normal occlusion;while the depth of it is larger than the normal group,the difference was statistically significant.Conclusions: 1.The dental arch and basal bone arch forms in maxilla and mandible were presented as personalized curves,which are highly correlated fitting with every constants of Beta function.2.The dental arch and basal bone arch of skeletal Class Ⅱ malocclusion are uncoordinated in the horizontal to and sagittal direction,while the good-fitting mathematical models of archforms can demonstrate the inharmonious factors,guiding the determination of the orthodontic treatment plan.