The Analysis Of CBCT Compare With Different Growth Period Mandibular In Angel ? Malocclusion Of Permanent Dentition

Objective:Taking cervical vertebra bone age as reference,we use oral cone CT(cone-beam computed tomography,CBCT)to compare different growth period Ann ? class wrong tooth mandibular condylar DCS and characteristics.By lateral sample survey and researching the early stage of the mandibular growth peak and the peak,we discuss the two times ? class or wrong tooth deformity mandibular condyle,structure features and development trend of DCS.Methods:This study selects 60 patients of Ann ? class from stomatological hospital of tianjin medical university orthodontic division between January 2014 and June 2014,excluding patients with osseous ? class and facial asymmetry,divide them into two groups of G1 and G2 group according to CVMS cervical vertebra(male with an average age 9.3 + /-9.3 years,while female with an average age of 8.9 + /-0.15years),G3-G4 group(male with an average age 13.4 + /-13.4 years,while female with an average age of 12.8 + /-0.14 years)and scan the patients with ICP CBCT respectively by the patients' sitting,and also use Invivo5 scanning to get and analyze the three parallel imag.1.To statistically analyze the data from left and right sides of mandibular and chin measurement.2.To statistically analyze the data from left and right sides of the temporomandibular joint measurement.All measuring project for each project measurement three times by the same operator take its mean value as the data,measured using SPSS 19.0 software for statistical analysis of the indicators of G1,G2 and G3-G4 phase are compared,and two by variance analysis and LSD method,inspection standard is 0.05.Results:1.This study measures Ann ? class wrong teeth in mandible through the use of CBCT,which shows that the difference among test length,width,height and growth trend of two measurements are very small.Difference between the average is less than 0.5 mm in length,Angle difference between the average is less than 0.3 °,and the measured repeat rate before and after was no significant difference(P < 0.05)which means the high precision of CBCT,in order to better determine the landmark measurement,repeated measurement difference was negligible.The numerical measurement results of Ann ? class of mandibular wrong tooth length,width,height and growth trend show statistically difference(P < 0.05),in which line is apart from the difference between mean within 0.5 mm,mean Angle difference within 0.2 °.The vast majority of measuring indexes had no statistical difference between left and right side(P < 0.05).2.This study measures Ann in different growth periods of this study ? class measurement after mandibular landmark of wrong tooth,which shows that the subjects G3-G4 period of mandibular length,height has significant growth.Men before and after is high,women behind becomes high.And Mandibular plane Angle of men keeps decreasing,while women in G3-G4 period decrease obviously,the men total reduction is more than women.3.Facial sagittal and vertical to the length to height of men is more than women,at the age of G3-G4 groups there was very significant difference,but G1,G2 and G3-G4 period before the back height ratio has no obvious difference.Y axis Angle of women is less than men in the G1 and G2 group,and group of men and women at the age of G4 G3-there was no significant difference.G1 and G2 stage level to form the perspective of women is more than men,have a significant meaning.In G1,G2 phase women compared with men,women are more prone to level to grow.But in the G3-G4 period level,compared to the men and women,there is no significant difference.In different periods and the same sex,level to form the Angle of men and women has obvious difference.4.Different periods Ann ? class or wrong tooth growth of condylar DCS shows obvious difference,which is shown as G1 and G2 stage significantly is less than the G3-G4 stage.Condyle DCS G3,G4 period is more slender than G1 and G2 stage,which means excessive vertical development.Joint concave is wide,and shallow.Compared with the G1 and G2 stage,G3-G4 period condylar position in concave joints is more forward than G3,G4 period in joint clearance and it is smaller than G1 and G2 stage,condyle is located in high in the concave joints.Conclusion:1.There are gender differences in different growth period of Ann ? class wrong tooth and in mandibular morphology,G3-G4 phase difference is markedly increased,but women mandibular length and vertical high is less than men.2.In the process of growth and development,the male mandibular growth direction is from down to front,and remained stable.While women mandibular growth direction of G1 and G2 stage tend to be more horizontal to grow,G3,G4 period growth is as the same as the growth of the male3.The different growth period Ann ? class or wrong tooth condyle growth trend show differences,G1 and G2 stage for the growth and development of the condylar DCS are much smaller than the G3-G4 period.Compared with the G1,G2,G3,G4 condylar is slender,vertical condylar shows excessive development;Joint concave is wide and shallow.4.G3-G4 is in front of G1 and G2 condylar position in concave joints.Condyle joints gap is small and it shows is high in the concave joints.