Morphological Characteristics of the Cranial Base of Early Angle's Class II Division 1 Malocclusion in Permanent Teeth

Abstract

: To investigate the effects of morphological characteristics of cranial base on malocclusion by analyzing characteristicsof sagittal and vertical facial types of Angle’s class II division 1 malocclusion so as to provide theoretical references for clinical diagnosisand correction of early Angle’s class II division 1 malocclusion in permanent teeth. We randomly selected lateral radiographs of the skull of80 patients at the age of 12–14 years old from the Department of Orthodontics, Stomatological Hospital, Shanxi Medical University, China.There were 20 cases of Angle’s class I malocclusion with average angle, 20 cases of Angle’s class II division 1 malocclusion with averageangle, 20 cases of Angle’s class II division 1 malocclusion with low angle, and 20 cases of Angle’s class II division 1 malocclusion with highangle. Winceph 8.0 software was used to measure 39 hard tissue markers and 13 indicators reflecting the characteristics of cranial basestructure. One-way t-test was used in the average-angle class II division 1 group and average-angle class I group. Least significant differencewas utilized in patients with different vertical types of class II division 1 malocclusion.nterior (S-N) and posterior (S-Ba) cranial baselengths, and total cranial base length (Ba-N) were significantly longer in the class II division 1 patients compared with the class I patients.Significant differences in anterior cranial floor base angle (CF-PM), middle cranial floor base angle (Ba-SE-PM), and posterior cranial baseinclination (SBa-FH) were determined between class II division 1 malocclusion and class I malocclusion patients. CF-PM angle and SBa-FH were smaller in class II division 1 subjects than in class I subjects. Ba-SE-PM angle and cranial floor base angle (Ba-SE-FMS) werelarger in class II division 1 subjects than in class I subjects. No significant difference in cranial base angle (N-S-Ba) and anterior cranial baseinclination (SN-FH) was detected between class II division 1 subjects and class I subjects. Morphology of cranial base and cranial floor basehas a significant effect on sagittal and vertical facial types of Angle’s class II division 1 malocclusion. The changes in the length of theposterior skull base and the inclination of the anterior skull base are mainly presented in the sagittal direction. Angle of cranial base andcranial floor base plays a certain role in vertical facial type of Angle’s class II division 1 malocclusion