| Objective:The purpose of this study:1.was to investigate the changes of the dental arch width and basal bone arch width,the location and degree of the changes,and the correlation among the changes,the sagittal anomalies and the vertical anomalies in different vertical skeletal types of Class II division 1 malocclusion.2.was to study whether or not the tooth have compensated,whether the buccolingual inclination of tooth are normal,and whether there is sufficienet alveolar bone thickness after tooth compensatory by the buccolingual inclination of tooth and the alveolar bone thickness in this malocclusion.3.was to provide reference and basis for clinic.Methods:The sample consisted of 80 adults were selected from 2015 to 2017 in Department of Orthodontics,Affiliated Stomatological Hospital,Kunming Medical University.There were 39 males and 41 females with an average age of 22.4 years.In the experimental group,there were 60 patients of Class II division 1 malocclusion.According to the FMA angle,60 patients were divided into high angle group,mean angle group and low angle group.Each group was 20 cases.The control group was 20 cases in the normal group of Class I mean angle patients.Through Minics18.0,the relative indexes of dental arch and basal bone arch width of maxillary and mandibular canines to second molars were measured.Buccolingual inclinations of the maxillary and mandibular tooth were examined.The measurements were performed 3,6,and 8 mm from the cementoenamel junction in the apical direction.The data has been statistically analysised.Results:1.Dental arch width was more stenotic in maxillary and mandible of high angle group and maxillary of the average angle group than the normal group.There was no significant difference among the maxillary and mandible of low angle group,the mandible of the average angle group and the normal group.With the increase of the facial height,the dental arch width was more stenotic.2.Compared with the normal group,basal bone arch were stenotic in maxillary and mandible of high angle group and maxillary of the average angle group.There was no significant difference among maxillary and mandible of low angle group,mandible of the average angle group and the normal group.With the increase of the facial height,the basal bone arch width were more stenotic.3.Under the same coronal plane,the basal bone arch width of the mandibular in the normal groups were larger than the maxillary,but the width of the maxillary basal bone arch in the high angle group,the average angle group and the low angle group were smaller than that of the mandible,and the difference was statistically significant(P<0.05)from the canine to the second molar.4.Dental arch width and basal bone arch were negatively correlated with ANB angle and FMA angle.The negative correlation with FMA angle is more obvious.With the increase of facial height,the transverse width is more stenotic.5.In the high angle group,the average angle group and the low angle group,the buccolingual inclination of the maxillary posterior tooth were smaller than the normal group,and the high angle group were the minimal and the low angle group were maximal.With the increase of the facial height,the buccolingual inclination of maxillary posterior tooth were smaller.The buccolingual inclination of the mandibular posterior tooth in the high angle group,the average angle group and the low angle group were larger than the normal group,of which the high angle was maximal and the low angle group was minimal.With the increase of the facial height,the buccolingual inclination of mandibular posterior tooth were larger.In the high angle group,the average angle group and the low angle group,the buccolingual inclination of the maxillary and mandibular anterior tooth were larger than that of the normal group,of which the low angle group was the largest and the high angle group was the smallest.6.The alveolar bone thickness of 3,6,and 8 mm from the cementoenamel junction in the apical direction in the maxillary and mandibular tooth of the high angle group were less than the normal group,the average angle group and the low angle group.There was no difference significant among the average angle group,the low angle group,the normal group.The maxillary and mandibular incisor have statistical significance(P<0.05),and another tooth had no statistical significance.Alveolar bone thickness of below CJE 3,6,and 8mm of the buccal side of maxillary mandibular canine is smaller than that of another tooth.Conclusion:1.There is no difference between Class ? division 1 malocclusion patients with high angle and Class I in the dental arch and basal bone arch of maxilla and mandible.The dental arch and basal bone arch in the maxilla and mandible of Class ? division 1 malocclusion patients with high angle and the maxilla of Class ? division 1 malocclusion patients with average angle are stenotic.With the increase of the facial height,the degree of stenosis is greater.2.Class ? division 1 malocclusion may have a negative correlation with vertical skeletal types,and a weak correlation with the sagittal skeletal pattern.The vertical discrepancies has a greater influence on the transverse width than the sagittal discrepancies.The vertical direction is a priority factor.3.When we need expansion,we need to consider the need for adjustment of the mandibular position and the matching of the upper and lower arch.4.The changes of transverse width in Class ? divisionl malocclusion may be related to pathogenesis and functional status.5.Maxillary posterior tooth in Class ? division 1 malocclusion patients with high angle and mean angle would be more palatally positioned than Class ?,and mandibular posterior tooth would be more tilted buccally.In order to establish a good occlusion relationship,the posterior tooth should pay attention to the control of torque early.When the need for adjustment of the mandibular position,the posterior teeth should apply positive torque,and the posterior mandibular teeth apply negative torque.No adjustment should be needed.It should be based on the occlusion relationship of the posterior tooth to maintain the inclination of the maxillary and mandible tooth,or to aggravate the compensation of the maxillary or mandibular.6.Compared with Class ?,there is sufficient alveolar bone thickness around the roots inClass ? division 1 malocclusion.The torque adjustment and change of the posterior teeth area are feasible.Alveolar bone thickness of Class ? division 1 malocclusion patients with high angle is less than Class ?,especially in the incisor area,and attention should be paid to both compensatory treatment and orthodontic orthognathic surgery. |
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