| Objective:Three-dimensional measurement and analysis were performed to describe the morphological features of the maxillofacial osseous tissue before and after the peak of skeletal Class ? malocclusion by cone-beam computed tomography(CBCT).To know more of the growth and development of skeletal Class ? malocclusion,gender differences and growth changes,To provide a theoretical basis for clinical diagnosis,the timing of treatment and the preparation of treatment plans.Method:60 patients(half male and half female,average age: 13.1 ± 0.92)were enrolled in the orthodontics department of stomatology hospital of Tianjin Medical University between August 2015 and June 2017,Cone beam CT scan obtained CBCT image data in ICP.The subjects were divided into two groups according to Hassel and Farman's cervical staging method.The before spurt group(male and female)and after spurt group group(male and female).The software Invivo5 was used to reconstruct CBCT data to establish a three-dimensional reference plane.Maxillofacial osseous tissue three-dimensional indicators were measured and analyzed.SPSS 24.0 was used to process the measurement results to analyze the paired t-test samples and independent t-test samples between groups.The results were analyzed and discussed.Result:1.This study of skeletal class?malocclusion maxillary landmark points measured shows that,before the peak period the maxillary length,the length of the palate,A position,the position of the maxillary central incisor don't have male and female gender differences,There was no significant difference between the two groups(P> 0.05).After the peak period,the maxillary length and palatal length of males were larger than those of females(P <0.05),and the height of maxilla was larger than that of females(P <0.05).Before the peak period,the width of upper facial and maxillary base,dental arch of maxillary molar width was wider in male than that of female.The width of maxillary base and maxillary molar area difference was statistically significant(P <0.05).After the peak period,the male width was greater than that of the female.Among them,the upper facial width was wider in male and has significantly different(P <0.01)maxillary base and maxillary molar area difference was statistically significant(P <0.05).2.In this study,for both gender,before and after the peak of maxillary measure up,found that along with the growth and development,the maxillary length were significantly increased,the average male growth of about 10.83 mm,the female is about 7.29 mm,the growth of both has significant statistical significance(P <0.01)The growth of male was greater than that of female,the average distance from point A to coronal plane increased by 1.4 mm,with no significant increase(P> 0.05);the height of vertical maxilla increased by about 6.14 mm in male,5.61 mm in female(P <0.01).The male growth rate was higher than that of the female.The width of the upper facial,maxillary base was significantly increased(P <0.01)There was no significant increase in dental arch of maxillary molar width(P> 0.05).Male male increased more than female.3.In this study,mandibular landmark points of skeletal Class II malocclusion were measured.The mandibular length and mandibular horizontal length of male patients before the peak were longer than those of females,Female ?Ar-Go'-Me,MP-SN is greater than male and gender difference was statistically significant(P <0.05).The male mandibular height was higher than that of female and gender difference was statistically significant(P <0.05).The width of the mandibular condyle was wider than that of the female,but the gender difference was not statistically significant(P> 0.05).The width of the mandible and mandibular molars were wider than that of the females.Statistical significance(P <0.05).In the late peak,the measurement items of the mandible in the sagittal,vertical and coronal directions were all greater than those in the male and the male had the larger mandible.4.In this study,mandibular was measured before and after the peak of males and females,and it was found that the length of mandible,the length of mandibular horizontal increased significantly,the average growth of males was about 13.97 mm and 9.03 mm,females was about 11.23 mm and 8.02mm(P <0.01).The height of mandibular ramus growth in vertical direction was 11.07 mm in males and 8.2mm in females,with a statistically significant increase(P <(P <0.01),male increased more than female.However,there was no significant difference in mandibular molar width(P> 0.05)between the male and the female before and after the peak.5.This study measured the temporomandibular joint before and after the peak,and found that the distances between T-Ar 'and Ar-Ar' increased significantly(P <0.01),and the changes of T-Fs 'and Fs-Fs' Statistical difference(P> 0.05).Conclusion:1.There were gender differences in mandibular morphology of patients with skeletal class II before and after the peak.2.Skeletal Class?patients has growth and development potential,both the maxillary and mandibular growth in three-dimensional directions.3.In skeletal Class?patients,there was obvious growth of maxillary shape before peak period in male and female adolescents,the length,height and width of maxillary increased,the maxillary dental arch grew narrowly and sharply,and male has more large amount of growth.4.In skeletal Class?patients,there was obvious growth of mandibular shape before peak period in male and female adolescents,mandibular length,width and height were increased,mandibular retrusion,lower incisors lip inclination and mandibular angle decreased,mandibular plane angle decreases,mandibular molars area compared with the upper jaw has reverse trend,male has greater growth than female.5.In the skeletal class?patients,the condyle moved downward and backward relative to the base of the skull,condyle length,width increased and the articular fossa deepen,it was relatively stable with the base of the skull and did not reconstruction with the displacement of the condyles,. |
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