The CBCT Study Of Cranial And Maxillofacial Skeletal Morphology In Skeletal Class Adult Patients With Different ? Vertical Facial Types

Objective: By measuring cranial and maxillofacial skeletal structure of skeletal class adult patients with different vertical facial types with the cone ?beam computed tomography(CBCT),this study aimed at studying the characteristics of cranial and maxillofacial bone.Methods: According to inclusion and exclusion criteria,83 skeletal class ? adult cases(31 male and 52 female cases,18 ? 40 years old age range)were selected into the experiment.Classification was defined by MP-SN value,and patients were divided into low angle(MP-SN<26°),average angle(26°?MP-SN<37°)and high angle(37°?MP-SN)groups.The morphologic,structural and positional characteristics of the cranial base,maxilla,mandible and chin were measured by Invivo and Win Ceph software.SPSS 21.0 was used for statistics to analyze the gender difference and the difference among groups.P<0.05 was considered as statistically significant.Results:1.Most length measurements were greater in men than in women significantly.2.SN-FH in the high-angle group was higher than that in the low-angle group,the saddle angle and the cranial base angle N-S-Ba were higher than that in the low-angle group,and SBa-FH was lower than that in the low-angle group.3.SNA in the high-angle group was less than that in the low-angle group,while A-Nper in the male high-angle group and NA-PA in the female high-angle group were higher than that in the low-angle groups.4.The vertical opening of mandible and mandibular angle in the high-angle group was larger than that in the low-angle group,and the horizontal opening was smaller than that in the low-angle group.In the high-angle group,the mandibular angle unit length,the width of condyle,the width between mandibular angles and the height of mandibular ramus were smaller,and the total length of mandible was larger.5.The ratio of chin thickness/chin height,chin minimum thickness and chin angle in the high-angle group were all smaller than those in the low-angle group.Conclusion:1.There is phase dorsal rotation in the plane of the anterior and posterior cranial base in patients with high angle.2.Patients with low angle are more sunken in the middle of the face.3.High-angle patients have a narrow and long chin,and low-angle patients have a better developed chin.