Mandibular changes in persons with untreated and treated Class II Division 1 malocclusion

The growth potential of individuals with Class II malocclusions is of interest to the practicing orthodontist because such malocclusions constitute a significant percentage of cases. The purpose of this study was to evaluate on cross-sectional and longitudinal bases the changes in mandibular length and relationship and maxillary-mandibular relationships in untreated Class II subjects from deciduous to permanent dentition and also to evaluate the effects of orthodontic treatment, with and without the extraction of first premolars, on these relationships. Class II samples were compared with matched normal, untreated individuals. The Class II Division 1 (Class II/1) untreated sample comprised 30 subjects, 15 males and 15 females. Each subject had a complete set of data at three stages of dental development—namely, Stage I, after the completion of eruption of the deciduous dentition; Stage II, at the time when the permanent first molars and most of the incisors have erupted (i.e., in mixed dentition); and Stage III, at the completion of eruption of the permanent dentition, excluding third molars. The Class II treated sample comprised 44 subjects (21 males, 23 females) treated with four first-premolar extractions and 47 subjects (20 males, 27 females) treated without extraction. Treatment was accomplished with the use of an edgewise appliance, appropriate extraoral traction, and Class II elastics. The extraction decision was based mainly on the presence of crowding and profile consideration. Records on 35 normal subjects (20 males, 15 females) were available from the Iowa Longitudinal Facial Growth Study. Cephalograms for the normal individuals were matched to the corresponding ages of the Class II cases. With regard to these findings, few consistent differences were noted between the untreated Class II/1 and normal subjects on cross-sectional comparisons. The differences in mandibular length and position were more evident in the early stages of development than at later stages. Longitudinal comparisons of growth profiles indicated that the growth trends were essentially similar between the untreated Class II/1 and normal subjects in the various parameters compared. The comparisons of growth magnitude indicated the presence of greater skeletal facial convexity in the untreated Class II/1 subjects, accompanied by a tendency for a more retruded mandible. Initial comparisons between the Class II/1 treated groups and normal subjects indicated that the Class II/1 malocclusions were associated with a larger overjet, deeper overbite, and greater ANB angle. After a 5-year treatment and observation period, an overall “normalization” in the mandibular and maxillary-mandibular skeletal relationships was noted in the treated Class II/1 subjects in both the extraction and the nonextraction groups compared with normal subjects. The changes were more pronounced in the extraction group.(Am J Orthod Dentofacial Orthop 1998;113:661-73)     

Skeletal and dental changes with nonextraction Begg mechanotherapy in patients with Class II Division 1 malocclusion

This prospective cephalometric study was undertaken to assess the mode and magnitude of Class II correction with nonextraction Begg mechanotherapy in growing children. The sample comprised subjects with similar malocclusion and age range (9-12 years) who were specifically selected for nonextraction Begg mechanotherapy. Cephalograms were analyzed to assess the skeletal, dental, and soft tissue changes that occurred after correction of the molar relationship, the overjet, and the overbite during the 9-month treatment period. The results revealed a significant improvement in the anteroposterior jaw relationship, suggested by the significant reduction in the ANB angle (1.62 degrees ) and in Wits AO-BO (1.42 mm). The mandibular length increase of 0.56 mm suggests that the Class II elastics used in nonextraction Begg mechanotherapy had a minimal stimulatory effect on mandibular growth. There was a significant increase in the anterior and posterior facial heights and the ramal height. Almost all of the dental changes were significant. The most striking feature were a significant retraction and extrusion of the maxillary incisors and proclination and intrusion of the lower incisors accompanied by extrusion of the mandibular molars. The maxillary incisors extruded by 1.64 mm under the influence of the undesirable downward component of the Class II elastic forces. The major contribution to overjet and molar correction was predominantly dentoalveolar.     

Treatment of a Class II Division 1 malocclusion.

This case was presented as part of the American Board of Orthodontics case displays at the 1999 AAO meeting. It was selected to be submitted for the publication in the American Journal of Orthodontics and Dentofacial Orthopedics by the ABO.     

Category 5: Class II Division 1 malocclusion.

This case report was part of a display of cases sponsored by the ABO after the board-certification process. The Summary of Treatment and records are reprinted here with minimal editing and reformatting, so the presentation resembles the actual documents submitted to the board.     

Treatment of a Class II Division 1 malocclusion with miniscrew anchorage

This case report describes the treatment of a 30-year-old woman with a Class II Division 1 malocclusion, characterized by a large overjet, a deep overbite, and a V-shaped maxillary dental arch. She had a convex profile with a retrognathic mandible and marked lip protrusion. Treatment involved extraction of 4 first premolars and miniscrew implant anchorage for space closure. The total treatment time was about 20 months. Ideal overjet and overbite relationships were established, and the facial profile was improved substantially. The 2-year follow-up records show a morphologically and functionally stable result.     

Early treatment of a severe Class II Division 1 malocclusion

This case report shows the effects of functional therapy at an early age in a severe Class II, division 1 malocclusion. Favorable changes in the profile and in the lip seal were achieved. The dental irregularity was treated by fixed appliances and extraction therapy. The patient and her parents were pleased with the final outcome.     

安氏Ⅱ类1分类患者后牙区颊侧皮质骨厚度分析

目的探讨不同年龄和性别的安氏Ⅱ类1分类患者后牙区颊侧皮质骨厚度的差异,为临床精准植入微种植钉提供理论依据。方法选取安氏Ⅱ类1分类患者多层螺旋CT三维重建影像资料88例,分为青少年男性组、青少年女性组、成年男性组和成年女性组4组,各组病例数为22例,测量上颌第二双尖牙和第一恒磨牙间及下颌第一、第二磨牙间,距离牙槽嵴顶3、5、7mm水平的颊侧皮质骨厚度,并对测量结果进行统计学分析。结果上颌第二双尖牙和第一恒磨牙间距离牙槽嵴顶3、5、7mm水平的颊侧皮质骨厚度分别为（1．21±0．21）mm、（1．29±0．20）mm和（1．42±0．19）nun;下颌第一、第二磨牙间距离牙槽嵴顶3、5、7mm水平的颊侧皮质骨厚度分别为（2．23±0．30）mm、（2．70±0．30）mm和（3．09±0．27）mm。青少年组与成年组之间在各水平的颊侧皮质骨厚度差异无统计学意义（P〉0．05）;男性与女性之间在各水平的颊侧皮质骨厚度差异无统计学意义（P〉0．05）。结论上颌第二双尖牙和第一恒磨牙及下颌第一、第二磨牙间皮质骨厚度在青少年与成人之间或男女之间无明显差异;以上部位距离牙槽嵴顶3、5、7mm水平的颊侧皮质骨厚度均可满足微种植钉植入要求。     

Sagittal and vertical changes after treatment of Class II Division 1 malocclusion according to the Cetlin method.

This cephalometric study was designed to evaluate the dentoskeletal anteroposterior and vertical changes produced by Cetlin therapy (lower lip bumper, ACCO, cervical headgear) to correct Class II Division 1 malocclusion in the late mixed dentition. All measurements were made on 2 lateral headfilms, at pretreatment and at 1 year after beginning treatment. The selected sample (n = 110; 67 boys and 43 girls; mean age, 10 to 11 years) and the control group (n = 100; 48 boys, 52 girls; mean age, 10 to 11 years) matched for number, age, and malocclusion. The average observation interval was 13 months. The final measurements between intervals were averaged and tested for significance by analysis of variance. A one-factor (group) repeated measure model and a two-factor (group and facial type) repeated measure model were fitted to each variable separately and significance values were set at P 相似文献