Cone-Beam CT Research On Nasal Septum' Characteristics In Skeletal Class ? Malocclusion

Objective:The purpose of this study was to observe the characteristics of nasal septum in skeletal III malocclusion of adult and adolescent patients by cone beam computed tomography and InvivoDental 5.1 software,and compared skeletal ?,?malocclusion features and differences in the nasal septum.Materials and Methods: 92 cases of patients(male 38,female 54),who visited department of orthodontics,affiliated Stomatology Hospital of Dalian Medical University in Dalian in January 2013-March 2015.The average age of adults and adolescents is 20.40 ± 2.79 years old and 13.02 ± 0.75 years old;according to the Steiner analysis in Chinese people with normal occlusion,measuring the mean SNA :82.8±4.0°,if SNA<78.8°,the development of maxillary is inadequate,if SNA measurements in between 78.8°-86.8°,the development of maxillary is normal.Therefore we divided into experimental and control groups,maxillary hypoplasia of Skeletal Class ? malocclusion as the experimental group,maxillary normal growth of Skeletal Class ? malocclusion as the control group,Skeletal ?malocclusion 46(male 18,female 28),skeletal?malocclusion 46(male 20,female26).Inclusion criteria: no facial trauma;no nasal surgery;no congenital cleft lip and palate;nasal septum without serious deviating;no history of orthodontic and orthognathic treatment.The equipment we use is KaVo 3DeXam cone beam computer tomography system of American KaVo company.Patients were sitting position,the Frankfort plane parallel to the ground,head midline and CBCT scanning device midline projection coincides,and fixed natural head position,meantime,shooting CBCT images in patients with central occlusion,and under the same conditions scanning CBCT images for all subjects.The CBCT images were analyzed usingthree-dimensional imaging software InvivoDental5.1,we could get a three-dimensional images about head.Find the most clear nasal septum in three dimensions sagittal tomographic image,intercepting a thickness of 2.0mm.Septal cartilage(SC)area,vomer area,perpendicular plate of ethmoid(PPE)area were measured,as well as the total area of the nasal septum(TS).To avoid the error,all the items must be measured by the same person within a certain time,measured again two weeks later,these two measurements were averaged.When selecting an area,the distance between points was less than 2mm.Then the measured data were inputted in SPSS 20.0 software,and we established a database and done statistical analysis.Measurement data were expressed as mean ± standard deviation.By one-sample Kolmogorov-Smirnov test,the area of SC,vomer,PPE and TS were all submitted to normal distribution.Variance Levene test,all data were consistent with homogeneity of variance.Two sets of data using independent sample t-test,when P<0.05,the difference was statistical,P <0.01,the difference was statistical significance.Results: 1.Gender comparison:whether the adolescent group and adult group,SC area in males are larger than females(P<0.01);2.Age comparison:SC area of adult group is larger than the youth group(P <0.01),but no statistically significant in PPE area;in the group of skeletal ?and ?,SC area of adult group are both larger than the youth group(P <0.05),but no statistically significant in PPE area of skeletal ?,have statistically significant in PPE area of skeletal ?(P <0.05);3.Skeletal ? and ?comparison:SC area of skeletal ? malocclusion in adult group is less than skeletal?malocclusion(P<0.05),adult group's PPE area in skeletal ? malocclusion is greater than Class ?(P <0.05);while the adolescent group had no statistically significant for each part of the area.Conclusions: 1.Gender comparison of SC:males are larger than females;2.Age comparison of SC:adult group is larger than youth group,after development of the growth,SC still have significant developmental trend.3.Skeletal ? and ?comparison of SC:SC area of skeletal ? malocclusion is less than skeletal ?malocclusion,by development of the growth,SC's development of skeletal ? isnot as good as skeletal ?malocclusion.Point:if accompanied by nasal disorders in skeletal ? malocclusion patients,it may be aggravated maxillary hypoplasia of skeletal ?.