Predictive factors of sagittal stability after treatment of Class II malocclusions

Objective:To determine the existence of factors permitting the prediction of sagittal stability after orthodontic treatment in patients with Angle Class II malocclusion.Materials and Methods:PubMed, EMBASE, and the Cochrane Library were searched up to March 2015. Inclusion criteria were longitudinal studies with at least 10 subjects investigating associations between at least one factor and stability, with an average minimum follow-up period of 2 years; stability measured using posttreatment sagittal dental changes; and orthodontic treatment including removable and/or fixed appliances with or without extractions. Two reviewers independently selected and assessed the quality of the articles.Results:The search strategy resulted in 1372 articles, of which 17 met the inclusion criteria. Large changes during treatment in molar and canine relationships were the only two factors found to be positively associated with relapse, but with limited evidence. Fourteen factors were found not to be predictive of relapse, also with limited evidence. These factors included treatment characteristics, patient pretreatment characteristics, and final posttreatment characteristics.Conclusions:There is currently limited evidence to support the influence of factors predictive of sagittal stability following Class II malocclusion treatment. More high-quality prospective studies are needed, and functional factors possibly affecting relapse also need to be further assessed.     

Treatment effects of the mandibular anterior repositioning appliance in patients with Class II skeletal malocclusions

Objective:To examine the changes produced by the mandibular anterior repositioning appliance (MARA) appliance and compare the treatment effects to an untreated Class II control group.Materials and Methods:Thirty consecutively treated patients were matched with an untreated control group. Lateral cephalograms were taken at T1, 5 months pre-MARA (CVMS 2.7); T2, immediately after MARA removal and prior to placement of full fixed edgewise appliances (CVMS 4.2); and T3, at least 2 years after MARA removal and completion of edgewise treatment (CVMS 5.4). The mean age of the MARA patients was 11.9 years for boys and 10.8 years for girls. Repeated-measures analysis of variance (ANOVA) was used to assess if the samples were morphologically comparable at the outset and to test if there were significant differences between the groups for the various increments of change. Given a significant ANOVA, the source of the difference was explored via Tukey-Kramer tests.Results:Restriction of maxillary growth and no significant mandibular growth were observed with the MARA appliance. The Class II correction was obtained mainly by slight maxillary molar distalization and intrusion, in addition to mesial migration of the lower molars and flaring of the lower incisors. No vertical effect was observed with this appliance.Conclusion:The MARA appliance was effective in the treatment of Class II malocclusions. Restriction of maxillary growth and dentoalveolar changes in the maxillary and mandibular arches were responsible for the correction of the Class II malocclusion. Significant mandibular growth did not contribute to this correction.     

Lower incisor extraction in Class I and Class II malocclusions: case reports

After a brief discussion of the indications/contraindications of extracting lower incisors as part of orthodontic treatment, five case reports are presented. These cases highlight that extracting lower incisors can be an accepted orthodontic option, not only in compromised class III treatments, but also in Class I and Class II malocclusions.     

Evaluation of apical root resorption following extraction therapy in subjects with Class I and Class II malocclusions

The purpose of this study was to determine the amount of root resorption during orthodontic treatment, and to examine the relationship between tooth movement and apical root resorption. Twenty-seven Class I and 27 Class II patients treated with edgewise mechanics following first premolar extractions were selected. The following measurements were made on the pre- and post-treatment cephalograms: upper central incisor to palatal plane distance, the inclination of upper central incisor to the FH and AP planes, the perpendicular distances from the incisor tip to the AP and PTV planes, and incisor apex to PTV. The amount of apical root resorption of the maxillary central incisors was determined for each patient by subtracting the post-treatment tooth length from the pre-treatment tooth length measured directly on cephalograms. Intra-group differences were evaluated by the Student's t-test and inter-group differences by the Mann-Whitney U-test. For correlations the Pearson correlation coefficient was used. The results show that there was a mean of approximately 1 mm (P < 0.01) of apical root shortening in Class I patients, but in Class II division I subjects the mean root resorption was more than 2 mm (P < 0.001). The inter-group differences were statistically significant. No significant correlations were found between the amount of apical root resorption and tooth inclination, or the duration of active treatment.     

Long-term profile changes associated with successfully treated extraction and nonextraction Class II Division 1 malocclusions

This study was undertaken to compare the post-treatment and long-term soft tissue profiles of successfully managed and stable Class II, division 1 malocclusions treated with either 4 first premolar extractions or nonextraction therapy. It was hypothesized that, if sound extraction decisions were made according to accepted treatment objectives and successful treatment outcomes were achieved, there should be no differences between groups in soft tissue profiles post-treatment and long-term post-retention. The sample consisted of 63 Caucasian adolescents (23 extraction, 40 nonextraction). Correction of the malocclusion was achieved using a combination of cervical headgear concurrent with mandibular growth and maxillary incisor retraction. Pretreatment, post-treatment, and long-term post-retention lateral cephalometric radiographs were evaluated. The soft tissue facial profiles of the extraction and nonextraction samples were the same following active treatment and long-term post-retention. Progressive flattening of the facial profile was observed in both samples. This flattening was attributed to the maturational changes associated with continued mandibular growth and nasal development and was not influenced by whether or not teeth were removed. Long-term lip positions were more retrusive than the ideals suggested by Ricketts and Steiner, but close to the values reported for normal, untreated adults of similar ages. The pretreatment position and thickness of the lower lip as well as the initial maxillomandibular skeletal relationship may be predictors of post-treatment or long-term lower lip position.     

Maxillary third molar position in Class II malocclusions: the effect of treatment with and without maxillary premolar extractions

The present study compared the number of erupted and functioning maxillary third molars and their mesio-distal angulation in patients with Class II malocclusions orthodontically treated with and without extraction of two maxillary premolars and fixed appliances. For that purpose, the records of 55 patients were selected, which were divided into two groups. Group 1 was treated without extractions and comprised 28 patient records (19 males and 9 females), with a mean age of 19.03 years [standard deviation (SD) = 2.33], treatment time of 2.59 years (SD = 1.08), and follow-up time of 6.48 years (SD = 2.42). Group 2 was treated with extractions and comprised 27 patient records (14 males and 13 females), with a mean age of 19.94 years (SD = 2.87), treatment time of 2.95 years (SD = 1.17), and follow-up time of 5.88 years (SD = 2.96). Analysis of the erupted and functioning maxillary third molars was conducted on the maxillary and mandibular dental casts. The mesio-distal angulations of the maxillary third molars were assessed on panoramic radiographs with the presence of both maxillary third molars. The results demonstrated that the number of erupted and functioning maxillary third molars was statistically greater (P = 0.01) in Class II subjects treated with extraction of maxillary premolars, when compared with those treated without extractions. The patients treated with two maxillary premolar extractions presented significantly smaller third molar mesio-distal angulations, that are more favourable to eruption, than those treated non-extraction.     

Class II division 1 malocclusion treated with extraction of upper first premolars: Case report

This report describes the treatment of a 13.7-year-old girl with a severe maxillary protrusion. She indicated Class II molar and canine relationship and showed 7-mm overjet, 0-mm overbite, and slight lower midline deviation with an unstable mandibular position. Treatment was started using a splint to stabilize the position of the mandible, followed by extractions of maxillary first premolars and fixed appliances to reduce lip protrusion. Molars were finished in a Class II relationship with canine guidance, and ideal overjet and overbite relationships were established. Also the final result was esthetically well balanced. The treatment results were stable 6 years after debonding.     

Long-term stability of miniscrew anchored maxillary molar distalization in Class II treatment

ObjectiveTo investigate treatment stability of miniscrew-anchored maxillary distalization in Class II malocclusion.Materials and MethodsThis retrospective study included a distalization (n = 19) and a control (n = 19) group; a patient group with minor corrections served the control. Lateral cephalograms of 38 adult patients were taken before (T0), immediately after (T1), and 3–4 years after (T2) treatment. Horizontal and vertical movement and tipping of the maxillary first molars (U6) and central incisors (U1) were measured along with skeletal craniofacial parameters at three time points to compare the two groups regarding the achieved treatment effects and their stability.ResultsTotal arch distalization therapy led to 4.2 mm of distal movement of U6 without distal crown tipping (0.6° of axis change) and 3.3° of occlusal plane steepening. Over an average retention period of 42 months, maxillary total arch distalization provided high stability of treatment results, showing the same amount of mesial movement (0.7 mm) as the control group.ConclusionsIn Class II treatment, miniscrew-anchored maxillary total arch distalization can provide stable distal movement of the maxillary first molars and central incisors.     

Correlations among craniofacial angles and dimensions in Class I and Class II malocclusions

In normal and Class I malocclusions, ramus and mandibular angles are found to correlate most strongly with cranial base dimensions rather than angles, whereas in Class II malocclusions these angles tend to relate more closely to the cranial base angles.     

安氏Ⅱ类1分类拔牙病例正畸治疗后后牙关系的稳定性研究

目的　探讨安氏Ⅱ类1分类患者正畸治疗前、后后牙关系的变化趋势,分析可能影响后牙关系复发的因素。方法　选取采用拔牙治疗的安氏Ⅱ类1分类患者29例,其中男12例,女17例。根据ANB角进一步分为牙性Ⅱ类14例,骨性Ⅱ类15例。分别对其正畸治疗前、后进行模型测量和X线头影测量。结果　所有患者的Ⅱ类磨牙关系在治疗后均得到明显改善,随访时仅有少量复发。牙性Ⅱ类患者治疗后下磨牙近中移动量(4·52±2·15) mm,大于上磨牙移动量(3·62±2·62)mm,而骨性Ⅱ类患者上下磨牙近中移动量相似,但ANB角由治疗前的(6·27± 1·08)°明显减小为(4·64±1·17)°。随访时两类错患者上下颌磨牙均近中移动,且上颌磨牙移动量大于下颌磨牙。多元回归分析提示下颌骨水平向生长和上前牙不齐指数与磨牙关系复发有关。结论　Ⅱ类错患者正畸治疗后磨牙关系较为稳定。牙性Ⅱ类错磨牙关系的解除有赖于上下颌磨牙相对移动调整,骨性Ⅱ类错则依靠上下颌骨间位置关系的改变。有利的下颌生长型和上颌前牙不齐程度等与磨牙关系的保持有密切关系。     

Skeletal Class III Malocclusion with Unilateral Congenitally Missing Maxillary Incisor Treated by Maxillary Protractor and Edgewise Appliances

This case report describes the orthodontic treatment of a 10-year-old female patient with a combination of Angle Class III malocclusion, a missing maxillary right lateral incisor, a supernumerary tooth with a short root on the lingual side of the maxillary incisor, a skeletal Class III jaw base relationship caused by a diminutive maxilla, and retroposition of the maxilla. We chose to close the space of the missing tooth, as well as the space created by extraction of the maxillary lateral incisor, by forward movement of the canine and premolars using a maxillary protractor with edgewise appliances. As a result, both the maxillary premolars and the molars were moved mesially, and a Class II molar relationship with tight interdigitation was achieved. Our results suggest that the combination of maxillary protractor and nontorque brackets was effective not only for correcting skeletal Class III malocclusion, but also for forward movement of the maxillary posterior teeth.