Mandibular displacement in Angle Class II, Division 2 malocclusion

The effect of the treatment of Angle Class II, Division 2 malocclusion was studied in 22 children by x-ray cephalometry and by recording the relation between the retruded and the intercuspal mandibular positions. The treatment was performed in three phases. In the first phase the upper incisors were proclined, and the deep bite was corrected with an upper removable plate. In the second phase the distal occlusion was corrected with an activator. The result was retained in the third phase with a second activator designed for retention. The relation between the retruded (RCP) and the intercuspal (ICP) mandibular positions was recorded with wax bites and dental casts mounted in a modified gnathothesiometer. The anteroposterior distance between RCP and ICP was large before the start of the treatment. The distance was unchanged after proclination of the upper incisors and correction of the deep bite but decreased after correction of the distal occlusion and increased again somewhat during the retention phase. The proclination of the upper incisors and the correction of the deep bite (phase one of the treatment) did not result in mandibular anterior positioning. This fact and the results of the recordings of the relation between RCP and ICP were interpreted as evidence that the mandible is not posteriorly displaced in Class II, Division 2 malocclusion.     

Extraction treatment of a Class II division 2 malocclusion with mandibular posterior discrepancy and changes in stomatognathic function

This case report describes the successful extraction treatment of a Class II division 2 malocclusion with mandibular posterior discrepancy and a congenitally missing maxillary lateral incisor on the left side. The posterior space in the mandibular arch was small, and the mandibular second molars were impacted, with distal tipping. The discrepancies in the maxillary and mandibular arches were resolved by extraction of the maxillary lateral incisor on the right side and the mandibular second premolars on both sides. The mesial movement of the mandibular first molars occurred appropriately, with the second molars moving into an upright position. A lip bumper was used with a preadjusted edgewise appliance in the maxillary dentition to reinforce molar anchorage and labial movement of the retroclined incisors. Despite the extraction treatment, a deep bite could be corrected without aggravation as a result of the lip bumper and utility arch in the mandibular dentition. Thus, an Angle Class I molar relationship and an ideal overbite were achieved. The occlusal contact area and masticatory muscle activities during maximum clenching increased after treatment. The maximum closing velocity and the maximum gape during chewing increased, and the chewing pattern changed from the chopping to grinding type. The findings in the present case suggest that the correction of a deep bite might be effective for improving stomatognathic function.     

Effects of orthodontic treatment on mandibular rotation and displacement in Angle Class II division 1 malocclusions

The aim of this retrospective cephalometric study was to investigate the effects of orthodontic treatment on rotation and displacement of the mandible in Angle Class II, division 1 malocclusions. Thirty patients in the treated group (15 boys and 15 girls; mean age at pretreatment, 12.27 +/- 1.36 years) were compared with 28 subjects who had untreated Class II, division 1 malocclusions (15 boys and 13 girls; mean age at T1, 12.01 +/- 0.07 years). The patients in the first group were treated nonsurgically, without extraction, and without the use of functional appliances. Cephalometric data were obtained from three lateral cephalograms per case representing pretreatment (T1), posttreatment (T2), and at least 2-years postretention (T3). Thirty-seven variables were measured representing craniofacial morphology, tooth measurements, and mandibular displacement. Some variables were obtained from cranial base, maxillary, or mandibular superimposition. Statistical significance was established at P < .05, P < .01, and P < .001. The findings indicated that orthodontic treatment of Class II, division 1 malocclusions induced a more vertical mandibular growth direction associated with an increased vertical displacement of pogonion. Occlusal or vertical movement of maxillary and mandibular molars was not correlated to mandibular rotation or horizontal displacement of pogonion. When compared with controls, the treated group did not exhibit a significant difference in mandibular rotation or occlusal movement of maxillary molars; however, it did show a greater occlusal movement of mandibular molars during treatment.     

A cephalometric comparison between Angle Class II, division 2 malocclusion and normal occlusion in adults

The lateral cephalometric radiographs of 56 adults with Angle Class II/2 malocclusion and of 81 persons with normal Class I occlusion are compared. The statistical analysis includes the calculation of the mean value, standard deviation and the determination of differences (Wilcoxon rank-test). Group characteristics are tested by stepwise discriminant analysis. The following statements regarding Angle Class II/2 as compared with normal Class I result from this study. The upper incisors are in a retruded position. The B-point is significantly retropositioned, whereas the pogonion is in a more normal position. The length of the mandibular corpus and the total length of the mandible are slightly diminished only. Normal values result for the size and position of the maxilla, the inclination of the mandibular corpus (angle between mandibular plane and NSe) and the gonion angle.     

Treatment of severe mandibular retrusion in class II, division 2 malocclusion.

The case of an adult patient with a severe mandibular retrusion of the Class II, Division 2 malocclusion type has been presented. The patient's marked anteroposterior discrepancy was complicated by the severe malocclusion. The solution to this case involved presurgical orthodontic treatment to allow for surgical mandibular advancement by a modified sagittal osteotomy and postsurgical orthodontic care for alignment of the dentition. A discussion of the importance of the patient's facial growth type for stable mandibular advancement has also been presented.     

Class II, division 2 treatment and mandibular growth

A statistical evaluation of relationships between orthodontic treatment of Class II, Division 2 malocclusion and mandibular growth and position, finding significant positive effects of treatment.     

Craniofacial analysis of the Tweed Foundation in Angle Class II, division 1 malocclusion

This study has defined the cephalometric values of the Craniofacial Analysis of the Tweed Foundation for a sample of Brazilian subjects. The sample consisted of 211 cephalometric radiographs from subjects aged 12-15, which were divided into two groups: Class II group, with 168 lateral teleradiographs (cephalograms) of white Brazilian subjects, with Angle Class II, division 1 malocclusion, of both genders (82 males and 86 females); and the Control Group, with 43 lateral teleradiographs (cephalograms) of subjects whose occlusion was clinically excellent, and also of both genders (21 males and 22 females). The teleradiographs were selected from the files of the Department of Orthodontics, School of Dentistry of Piracicaba, State University of Campinas, previously to the orthodontic treatment. The results demonstrated no sexual dimorphism for each group, as attested by the Student's t-test. The exploratory analysis (+/- 0.5 standard deviation) enabled the tolerance limits to be determined and a Craniofacial Analysis Table to be constructed using the respective cephalometric intervals. In addition, the difference between the two groups was not statistically significant according to the maxilla position. The maxilla was in a good position in relation to the cranial base. On the other hand, the mandible was retruded in relation to the cranial base in the Class II cases. The skeletal pattern was not defined because only the Facial Height Index (FHI) showed a vertical pattern in Class II subjects, while the Y Axis, SN.PlO, SN.GoMe and FMA values did not show any statistically significant difference between the groups. The Class II division 1 subjects showed lower incisors more labially tipped and a convex facial profile.     

Class II, division 2 malocclusion. To extract--or not extract?

Identical 13-year-old twin boys with Class II, division 2 malocclusions are treated at the same time, one with a full complement of teeth and the other with extraction of the first bicuspids.     

安氏Ⅱ类2分类错畸形非拔牙矫治前后颏部形态的变化

目的:利用X线头影测量技术,研究正畸非拔牙治疗对安氏Ⅱ类2分类错畸形颏部形态变化的影响。方法:选择20例恒牙期安氏Ⅱ类2分类错畸形的患者,利用MBT直丝弓矫治器进行矫治。经X线头影测量,对头颅侧位片进行定点、描记后,测量矫治前、后颏部形态、上下颌骨位置、下颌平面角等形态结构,采用PASW statistics18对所得数据进行统计学分析。结果:治疗后,随着上颌切牙舌向倾斜的矫正,下颌骨向前下位移,下面高增加。上、下唇与E线的距离趋于正常。颏点位置前移,颏凹陷度以及颏唇沟的深度变浅,颏曲度增加,与矫治前相比有显著性差异(P<0.05)。结论:安氏Ⅱ类2分类错畸形经正畸治疗后能够改变颏部的位置和形态,使面形更接近理想面形。     

Lip shape and position in Class II division 2 malocclusion

OBJECTIVE: To determine whether differences exist in the shape and position of the lips between Class II division 2 and Class I malocclusions. MATERIALS AND METHODS: Lateral cephalometric radiographs of subjects with Class II division 2 (n = 30) and Class I (n = 30) incisor relationships were scanned at 300 dpi to produce digital images. These were subsequently digitized in random order. Twenty-one landmarks characterizing the upper and lower lips and the maxillary and mandibular central incisors were digitized. Procrustes algorithms optimally superimposed the landmark configurations to standardize size, location, and orientation. Discriminant analysis of the principal components of shape determined the differences between the Class II division 2 and Class I groups. RESULTS: The shape and position of the upper and lower lips differed significantly between the Class II division 2 group and the Class I group (P < .001). Principal component (PC) 1 (46% of the variance) involved an increase in the thickness of the upper and lower lips in the Class II division 2 group. PC2 (11% of the variance) was characterized by a relatively higher lip line in the Class II division 2 group. CONCLUSIONS: The shape and position of the lips differ between Class II division 2 and Class I malocclusions.     

Asymmetric extraction treatment of an Angle Class II Division 2 subdivision left malocclusion with anterior and posterior crossbites.

This case was chosen by the CDABO student case selection committee for publication in the AJO/DO.     

Activator and Begg appliance management of a severe Angle Class II, division 1 malocclusion

A male patient aged 12 years 11 months presented with the chief complaint of prominent, spaced upper teeth and was keen to overcome his dental problem.     

Rationale of treatment for Class II division 2 malocclusion

Class II, division 2 malocclusion is a clinical entity which presents considerable difficulty in the provision of a stable treatment result. This article sets out the problems encountered, reviews teaching on the subject over a 20-year period and attempts to rationalize the current approach to treatment. The rationale presented shows the three-dimensional nature of the occlusal problem, and discusses the justification for expansion and proclination of lower incisors in relation to soft tissue influences and stability. The importance of correcting edge-centroid relationship and reducing inter-incisor angle is stressed. Non-extraction therapy, with some lower arch expansion and incisor advancement, is recommended and the reasoning behind this is explained with a case example to illustrate the points involved.