| Objective:To classify patients with skeletal class III malocclusion in the mixed dentition and early permanent dentition according to the Baccetti cervical vertebrae age staging method,and apply the maxillary anterior traction combined with repeated scaling to correct the anterior and posterior cephalic lateral slices of each group of patients.The changes of soft and hard tissues of maxillofacial region were evaluated,and the effect of maxillary anterior traction combined with repeated expansion and contraction on skeletal class III malocclusion was evaluated.Methods:58 patients with skeletal class III malocclusion were enrolled in our hospital from November 2016 to May 2018.There were 28 male patients and 30 female patients,aged 7.92-13.44 years.Inclusion criteria:skeletal class III malocclusion,molar relationship is mesiocclusion,the mandible is too large,the anterior process of the ankle,the sagittal direction of the face is underdeveloped,∠ANB≤0°,the anterior teeth are ruminating,the mandible cannot retreat to the opposite edge,upper and lower teeth The bow width is basically normal.All patients underwent X-ray of the lateral side of the skull before and after treatment.The bone age was staged according to the Baccetti cervical vertebral stages method.The patients were divided into the pre-peak group(CS1～2),the peak group(CS3～4),and the late peak group(CS5～6).Using SPSS22.0 statistical analysis software,paired t-test was performed on the cephalometric measurements before and after treatment in each group to evaluate the clinical effect of anterior maxillary anterior and posterior retraction in the treatment of skeletal class III malocclusion in the dentition period,and different bone ages.The cephalometric measurements between the groups were analyzed by analysis of variance to compare the effects of different bone age groups.Results:1.After the treatment of maxillary protraction combined with repeated expansion and contraction,each group of patients had sagittal and vertical changes,the maxilla was displaced forward,the mandible was displaced downward and backward,and the anterior teeth were normally covered.2.On the one hand,the release of rumbling comes from the frontal displacement of the maxilla and the posterior and posterior rotation of the mandible,and on the other hand,the anterior and posterior teeth are inclined and the tongue is inclined.3.As the bone age increases,the course of traction in the front becomes longer;at the same time,the bony effect becomes smaller and the tooth effect increases.4.The correction time of different bone age groups was different.The peak pre-group(group A)averaged 5.51 ± 1.06 months,the peak group(group B)averaged 5.43±0.85 months,and the peak group(group C)averaged 8.35±2.37 months.There was no significant difference between group A and group B(P>0.05).There was significant difference between group A and group C,group B and group C(P<0.01).Conclusions:1.Patients with different bone age grouped with skeletal class Ⅲmalocclusion can achieve significant correction effect after anterior traction combined with repeated expansion and contraction treatment.2.For patients with skeletal class Ⅲ malocclusion at the pre-peak and peak of growth and development,more bone effect can be produced,less tooth compensation。3.For patients with skeletal class Ⅲ malocclusion at the end of the growth and development peak the bony effect becomes smaller and the dentin compensation becomes larger.4.Patients with skeletal class Ⅲ malocclusion at the pre-peak and peak periods were treated faster than the late-stage group. |
