The Study Of Nasal Soft Tissue Profile For Patients With Class â…¡ Division 1 Malocclusion

Objective:The aims of this study were to investigate nasal shape differerces between patients with Class I malocclusion and patients with Class II Divisionl malocclusio,differences between male and female patients by cephalometric analysis.Anymore,nasal shape changes followed by orthodontic treatment or growth and development were also investigated.All of this was to give proposal for making orthodontic plans.Methods:There were two compositions in our study.1.The first part was the analysis of the nasal shape differerces between patients with ClassⅠmalocclusion and patients with ClassⅡDivision 1 malocclusion.differences between male and female patients. 114 patients with Class I malocclusion or with ClassⅡDivision 1 malocclusion in fastigium of growth and development were selected (age 11～14 years).The male and female ones were equal in each malocclusion.Taking lateral cephalometric radiographs in relaxed head position.Twenty two parameters were gained by the viewpoint of ten orthodontic doctors and the proportion of each positions on nasal were awared.Making the definition of coordinate system with the the true horizontal plane to measure parameters of nasal dorsum,nasal tip and nasal bridge.The date were analyzed of with SPSS 16.0 software package,using chi-square test for data of RXC table (χ2 test) for the results of linguistic form used for classifying nasal profile shapes and Independent-Sampls T test between two malocclusions,between male and female patients.2.The second part was to investigate nasal shape changes followed by orthodontic treatment or growth and development.It was continued to analysis the nasal sharp of the patients with ClassⅡDivision 1 malocclusion.114 patients in fastigium of growth and development were divided in two groups:group A with 57 nonextraction subjects,group B with 57 extraction subjects,who were followed from ages 11 to 14 years.Pretreatment was T1 stage,aftertreatment was T2 stage.Take 57 patients after fastigium as negatively control group C(age 11～14 years at T1,current time at T2).The method of mathematical descriptions of nasal sharp were also used in this part.Anymore,the parameters related to maxillary and mandibular,forehead,upper lip,nasal bone were measured on lateral cephalometric radiographs in two stages.The date were analyzed of with SPSS16.0 software package,using paired t test in group and LSD(Least-Significant Difference) among groups.Results:PartⅠLinguistic descriptions of nasal sharp:ClassⅠmalocclusion contrast to ClassⅡ,Division 1 malocclusion,①the percentage of form of nasal dorsum,start point of nasal dorsum's bump,form and direction of nasal tip.form of nasal bridge,vertical position of nasal tip and height of nasal tip in the sagittal direction were not found to be significantly different between two malocclusions;②the percentage of "Straight" form of nasal dorsum,"Round" form of nasal tip,"Convex" form of nasal bridge and "Upper" diretion of nasal tip were larger than others.Male contrast to female patients,①the percentage of form of nasal dorsum,form of nasal tip,form of nasal bridge, vertical and height position of nasal tip were found to be significantly different;②position of nasal dorsum's bump,direction of nasal tip were not found to be significantly different.Mathematical descriptions of nasal sharp:ClassⅠmalocclusion contrast to ClassⅡDivision 1 malocclusion,there was no difference in the lenghth of each composition of nasal,but the curve of nasal dorsum,nasal tip,nasal bridge were found to be significantly different.Male contrast to female patients,the lenghth of each composition of nasal were lower than male patients,female ones' nasal dorsum looked more tortuously,the curve of nasal tip looked more round and they had little protrusion nasal.PartⅡLinear measurements were found to be significantly different between two stages in group A and group B (P<0.05).The width of nasal dorsum,the length of nasal base, the thicknesses of nasal was found to be significantly different between two stages in group C(P<0.05).The length of nasal dorsum,the height of nasal base,the nose frontal angle were found to be significantly different between treatment group and nontreatment group(P<0.05).Conclusions:(1) There were no difference in the length of each composition of nasal between ClassⅠand ClassⅡDivision 1 malocclusion,but the form of the later form of nasal tip looked more round,dirction of nasal tip was more uptumed.All of that resulted to the position of esthetic line moving backward.(2) Male contrast to female patients,the lenghth of each composition of nasal were lower than male patients,female's nasal dorsum looked more tortuously,the curve of nasal tip looked more round and they had little protrusion nasal.(3) Orthodontic treatment can promote growth of nasal in vertical direction,while has no significantly influence on nasal sharp.