Profile changes associated with different orthopedic treatment approaches in Class III malocclusions

The aim of this study was to evaluate and compare the soft tissue effects of chincup (CC), chincup plus bite plate (CC+P), and reverse headgear (RHg) therapies with each other and with an untreated control group (C). The material consisted of lateral cephalometric and hand-wrist films of 59 Class III cases and 20 nontreated control subjects. Thirty-one cases were treated with CC, 14 with CC+P, and 14 with RHg, and Class I relation was achieved. The mean pretreatment ages were approximately 11 years and the observation period was one year. The cephalometric films were analyzed according to the structural superimposition method of Bj?rk. All tracings were double digitized, and the measurements were calculated by a computer program (PORDIOS). Treatment and control changes within the groups and the differences between the groups were analyzed statistically. Forward positioning of the maxilla was significant in the RHg group, whereas the mandible was positioned backward significantly in all the treatment groups. Posterior rotation of the mandible was significant in the CC+P and RHg groups. The overjet increased and the overbite decreased significantly in all the treatment groups. Forward movement of soft tissue A and upper lip was significant in all groups, whereas more pronounced in the CC+P group. The soft tissue changes in the mandibular region were significant in the CC and CC+P groups, whereas in the maxillary region more significant and similar improvements were obtained by CC+P and RHg treatments. Longterm studies are required to confirm the stability of these changes.     

An orthopaedic approach to the treatment of Class III malocclusions in the early mixed dentition

The aim of this investigation was to study cephalometrically the skeletal, dental and soft tissue modifications induced by a Delaire facemask and Bionator III appliance in a sample of 30 patients (17 boys and 13 girls), aged 4.1-9 years [mean 5.85 years, confidence interval (CI) 5.41-6.29], in the early mixed dentition with a skeletal Class III malocclusion caused by maxillary retrognathism (group 1) and compared with a control sample of 24 subjects (14 boys and 10 girls), aged 4-9 years (mean 5.97 years, CI 5.35-6.58) with untreated Class III malocclusions (group 2). For each patient a lateral cephalogram was taken before treatment (T0), after facemask removal (T1), and at the end of the retention period with a Bionator III (T2). Cephalometric analysis was carried out. The post-treatment cephalometric values in the treated group showed a forward displacement of the maxilla resulting in a statistically significant increase (P < 0.001) in the SNA angle, A-NPg (mm) and PNS-A (mm) linear values. There was a clockwise rotation of the mandible, with a decrease in the SNB angle and a satisfactory correction of the Class III relationship. The beneficial effects on the facial profile were confirmed by an increase in UL-EL distance and in NB--HL and NsPgs--HL angles, and by a decrease in the facial convexity angle. These findings indicate that the Delaire facemask and Bionator III treatment is effective for correcting skeletal Class III malocclusions caused by maxillary retrognathism in the early mixed dentition.     

Level anchorage system treatment of Class III malocclusions

Very few definitive clinical papers have been written on exactly how to treat a Class III malocclusion. This article describes the rationale and the step-by-step procedure for the successful orthodontic treatment of Class III malocclusions.     

Finite-element morphometry of soft tissue morphology in subjects with untreated Class III malocclusions.

Soft tissue dynamics may contribute to maxillomandibular allometry (size-related changes in shape) associated with the development of Class III malocclusions. Lateral cephalographs of 124 prepubertal European American children were traced and 12 soft tissue landmarks were digitized. Resultant geometries were normalized, and Procrustes analysis established the statistical difference (p<0.001) between mean Class III and Class I configurations. Comparing the Class III configurations with normals for size-change, color-coded finite element analysis revealed a superoinferior gradient of positive allometry of the Class III facial nodal mesh. A conspicuous area of negative allometry (approximately 40%) was localized near soft subspinale, with a approximately 70% increase in size in the mental region. For shape-change, the Class III facial mesh was isotropic, except in the anisotropic circumoral regions. Conventional cephalometry revealed that about 50% of linear and 75% of angular parameters differed statistically (p<0.001). Soft tissue dynamics during early postnatal development may contribute to the development of Class III malocclusions.     

Cephalometric analysis in cases with Class III malocclusions

Various orthodontic class III anomalies, classified into several experimental groups, and eugnathic occlusions serving as controls were studied by roentgencephalometry. The objective of the study was to detect possible distinctions in the quantitative values of two variables chosen and to select the variables which most significantly discriminate the group of class III orthodontic anomalies. Attempts were made to ascertain whether or not there were sex-related differences. The teleroentgenograms of 269 examines, aged 10-18 years, of both sexes were analyzed. The experimental group consisted of 89 examinees class III orthodontic anomalies. The control group consisted of 180 examines with eugnathic occlusion. Latero-lateral skull roentgenograms were taken observing the rules of roentgenocephalometry. Using acetate paper, the drawings of profile teleroentgenograms were elaborated and the reference points and lines were entered. A total of 38 variables were analyzed, of which there were 10 linear, 19 angular, and 8 variables were obtained by mathematical calculation; the age variable was also analyzed. In statistical analyses an electronic computer was used. The results are presented in tables and graphs. The results obtained showed that: --compared to the findings in the control group, the subjects in the experimental group displayed significant changes in the following craniofacial characteristics a negative difference in the position of the apical base of the jaw, manifest concavity of the osseous profile and diminished convexity of the profile of soft parts, retroinclination of the lower incisors, mandibular prognathism, increased mandibular angle and increased mandibular proportion compared to maxillary and the anterior cranial base; --with regard to the sex of the examinees, only four linear variables of significantly discriminating character were selected, so that in can be concluded that there were no significant sex differences among the morphological characteristics of the viscerocranium.     

Treatment of Class III malocclusions

Current knowledge about cranio-facial growth, the identification of different anatomic types by architectural cephalometric analysis, the new therapeutic methods and a multidisciplinary have changed the mode and the results of these treatments. However the key of success is: begin the treatment as soon as possible. The correction of skeletal anomalies and the normalization of all the oro-facial functions need a lot of time. It is advisable to be efficient at the good time with the good appliance. The quality of the result will be estimated at the end of the growth. In this way, a lot of orthognathic surgery can be avoided. So, certainly the results reward the efforts.     

Occlusal justification of early treatment of Class III malocclusions

Authors mostly admit that Class III treatment has more chance of success and stability if it is carried out precociously. Their conviction is primarily based on the use of patient's growth potential. This aspect does not seem to be the main interest of early treatment. The length of the occlusal plane and its impact on mandibular movements (mastication), which can influence growth and maxillomandibular relationships, accounts or even constrains to act as soon as possible. The fundamental objective of early Class III treatment would be the reorientation of the occlusal plane and the rehabilitation of mastication would be the final goal, ensuring an active and physiological result's retention.     

Skull thickness in patients with skeletal Class II and Class III malocclusions

Authors – Arntsen T, Kjær I, Sonnesen L Objectives – To measure skull thickness in a group of subjects with skeletal Class II and a group with skeletal Class III malocclusion and compare these results with a group with Class I occlusion. Setting and Sample Population – Department of Orthodontics, School of Dentistry, University of Copenhagen. The Class II group comprised 25 females aged 17–42 (mean 26.0). The Class III group comprised 53 patients, 29 females aged 17–39 (mean 24.2) and 24 males aged 17–38 (mean 22.6). The control group comprised 39 subjects, 19 females and 20 males, aged 22–30, with a neutral occlusion and normal vertical and sagittal jaw relationship. Material and Methods – The thickness of the frontal, parietal and occipital bones was measured on lateral radiographs of patients with skeletal Class II and Class III and compared with the control group. Method error ranged from 0.30 to 0.60 mm and reliability coefficients from 0.79 to 0.97. Unpaired t‐tests were used for evaluating differences in thickness. Results – Females with skeletal Class II malocclusion had a significantly thinner occipital bone and thicker frontal bones than the control females. Skull thickness in Class III malocclusion was comparable to the control group. Conclusion – The most important outcome of this study was reduced skull thickness in the occipital area and thickening of the frontal bone in females with skeletal Class II malocclusion compared with females with Class I. Deviations in the theca cranii are thus associated with skeletal Class II malocclusions.     

Ⅱ类高角患者矫治后颅面结构变化的临床研究

目的 :探讨Ⅱ类高角患者矫治中应注意的问题。方法 :采用Tweed Merrifield骨骼测量法对 14例安氏Ⅱ类高角病例治疗前后组织改变进行头影测量分析比较。结果 :( 1)FMIA及Z角在治疗后增加并具有显著差异 (P <0 .0 5 ) ;( 2 )ANB治疗后减小 ,SNB增大且治疗前后具有显著差异 (P <0 .0 5 ) ;( 3)牙合平面角 (OP FH)治疗前后无显著差异 (P >0 .0 5 )。结论 :治疗过程中 ,我们成功地控制了 :( 1)面部垂直向的生长 ;( 2 )牙合平面的旋转 ;( 3)下切牙直立于基骨上。取得了良好的治疗结果 ,使颜面更加协调美观     

Midfacial and mandibular morphometry of children with Class II and Class III malocclusions

There is insufficient evidence in conventional cephalometric analysis of the actual sites of putative maxillofacial change in Class II and Class III malocclusions. The purpose of this study was to provide more information about the morphological characteristics of the midfacial complex and mandible in children with Class II or III malocclusions. Seventy children with Class II, division 1 malocclusion and 70 children with Class III malocclusion were compared with 70 children with normal occlusion. This study was conducted to carry out geometric morphometric assessments to localize alterations using Procrustes analysis and thin-plate spline analysis. Procrustes analysis indicated the midfacial and mandibular morphologies differed between normal occlusion subjects and subjects with Class II or Class III malocclusion (P<0.0001). The deformations in subjects with Class II malocclusion may represent a developmental elongation of the palatomaxillary complex and a shortening of the mandible anteroposteriorly, which leads to the appearance of a protruding midface and retruding mandibular profile. In contrast, the deformations in subjects with Class III malocclusion may represent a developmental shortening of the palatomaxillary complex and elongation of the mandible anteroposteriorly, which leads to the appearance of a retrognathic midface and prognathic mandibular profile.     

Orthodontic treatment of openbite and deepbite high-angle malocclusions.

The aim of the investigation was to assess the effect of orthodontic treatment on dentoskeletal morphology in children with openbite and deepbite high-angle malocclusion. Subjects (n = 54) in the mixed dentition with a hyperdivergent mandibular plane angle (high-angle, NSL/ML > or =40 degrees) were surveyed. Pre- and posttreatment lateral roentgenographic cephalograms were analyzed. Subjects were divided into three subgroups according to the amount of pretreatment overbite: < 0 mm = insufficient/no compensation (openbite); 0-4 mm = acceptable compensation (normal overbite); >4 mm = overcompensation (deepbite). Pretreatment, 20% of the high-angle cases exhibited insufficient dentoskeletal compensation (overbite <0 mm), and 35% displayed overcompensation (overbite >4 mm). Influences of habits such as lip sucking and tongue-thrust swallowing were more common in the openbite group. No major difference in treatment approach could be found between subgroups. In 82% of the openbite group and 90% of the deepbite group, overbite was corrected by orthodontic treatment. The mandibular plane angle was unaffected in both groups. The mechanisms of overbite correction differed between groups. The openbite group exhibited a significant decrease in interjaw-base angle. Increases in anterior and posterior dentoalveolar heights were comparable. The deepbite group showed no significant changes in skeletal morphology. The increase in dentoalveolar height was approximately twice as large posteriorly as anteriorly. The majority of children (80%) with high-angle morphology had a positive pretreatment overbite, thus exhibiting compensation of jaw-base hyperdivergency. Orthodontic treatment of high-angle malocclusions did not influence the mandibular plane angle in openbite or deepbite cases. Overbite correction was accomplished by tipping the maxilla downward anteriorly in openbite subjects, and by controlling incisor eruption in deepbite subjects.     

拔除下切牙正畸矫治的临床研究

目的:探讨拔除正畸患者下切牙的各种适应证及矫治方法。方法:临床选择42例患者(男16例,女26例),具体分为4种情况:Bolton指数不调,前牙比过大;III类错前牙反;先天缺1颗下切牙;某些牙周病等。治疗之前均采用拔除单个下切牙或拔除下切牙外还配合其它牙齿的拔除,使用标准方丝弓矫治技术和其它辅助治疗方法。结果:前2种情况拔除单个下切牙,第3种情况拔除1个下切牙外还拔除上颌2个第一前磨牙,下颌个别牙需要磨改外形,第4种情况拔除1个下切牙外上颌多个牙要配合邻面去釉,42个病例均取得满意的矫治效果,前牙覆、覆盖正常,后牙咬合关系好。结论:认真掌握好临床拔除下切牙的适应证并配合其它方法,能取得满意的临床矫治效果。     

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.     

Arch widths in adults with Class I crowded and Class III malocclusions compared with normal occlusions

OBJECTIVE: To test the hypothesis that there is no difference between adults with Class I crowded (CICR), Class III (CIII), and Class I normal (CIN) occlusions with respect to (1) arch widths, (2) width of the maxillary and mandibular arches, (3) gender dimorphism within groups, and (4) gender comparisons. MATERIALS AND METHODS: Samples of 39 CICR subjects, 40 CIII subjects, and 40 CIN subjects were studied. All subjects were white Americans with no history of orthodontic treatment. An analysis of variance and Duncan's test statistically compared the groups and genders. RESULTS: The CICR group had mean maxillary and mandibular intermolar and alveolar arch widths significantly smaller than the CIN group. The CIII group had mean maxillary intermolar and alveolar arch widths significantly smaller than the CIN group. Mean maxillary and mandibular intercanine arch widths were similar in the three groups. The CICR and CIN groups had similar mean maxillary/mandibular intermolar and alveolar differences significantly larger than the negative differences observed in the CIII group. Gender dimorphisms were identical in the CIII and CIN groups. The CICR group differed by not having a gender dimorphism in the maxillary alveolar width and having a gender dimorphism in the mandibular intercanine width. Gender comparisons between groups were similar in intercanine widths but differed in other widths. CONCLUSIONS: The hypothesis was rejected by the findings of this study.     

Hyoid bone position and orientation in Class I and Class III malocclusions.

Various studies have documented a variability of hyoid bone position in relation to changed mandibular position or head posture. The aim of this study was to investigate the hyoid bone position and inclination on the cephalometric radiographs of two groups of patients exhibiting Class I and Class III malocclusions. The radiographs were taken in both centric occlusion and wide-opened mandibular position, and 17 measurements were performed on both tracings. The findings reveal a statistically significant difference in the position and inclination of the hyoid bone in the two groups; Class III patients, especially the boys, show a more anterior position of the hyoid bone and also a reverse inclination. This might have an implication on the function of the suprahyoid and infrahyoid muscles and thus on the direction of mandibular growth.     

Dentoskeletal treatment changes in Class II subdivision malocclusions in submentovertex and posteroanterior radiographs.

The objective of this study was to evaluate the dentoskeletal changes consequent to orthodontic treatment in subjects with Class II subdivision malocclusions, treated with asymmetric extractions, compared with a normal-occlusion control group. The sample consisted of 3 groups, with 30 subjects in each: normal-occlusion subjects (group 1), untreated Class II subdivision subjects (group 2), and Class II subdivision patients treated with asymmetric extractions (group 3). All subjects had a full complement of permanent teeth at the beginning of treatment. The average ages of the subjects were 22.42, 15.76, and 18.57 years, respectively, in groups 1, 2, and 3. Measurements of relative differences in the spatial position of dental and skeletal bilateral landmarks were obtained from the submentovertex and posteroanterior cephalometric (PA) radiographs. The t test for independent samples was used to compare group 1 with groups 2 and 3 at different times. Results from the submentovertex radiograph showed that asymmetric extractions in Class II subdivision malocclusions will maintain the differences in the anteroposterior positions of right and left, maxillary and mandibular first molars, as would be expected with the treatment protocols used. There were no significant skeletal changes that could be attributed to the treatment approaches investigated or transverse collateral effects with the asymmetric mechanics used. It was also demonstrated that treatment of Class II subdivision malocclusions with asymmetric extractions produced corrections of maxillary and mandibular dental midline deviations with the midsagittal plane, without canting the occlusal plane or any other investigated horizontal plane, as seen in the PA radiograph. Treatment of Class II subdivision malocclusions with asymmetric extractions constitutes a beneficial approach to this problem.     

Comparison of oropharyngeal airway dimensional changes in patients with skeletal Class II and Class III malocclusions after orthognathic surgery and functional appliance treatment: A systematic review

ObjectiveTo compare the dimensional changes in the oropharyngeal airway in patients with skeletal Class II and Class III malocclusion before and after orthognathic surgery and treatment with a functional appliance.MethodsThe protocol was developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) and was registered to the International Prospective Register of Systematic Reviews (PROSPERO) under the registration number CRD42020170901. Furthermore, the reporting of the present SR was performed based on the PRISMA checklist.ResultsThe use of removable functional appliances increased the volume of the oropharyngeal airway in patients with skeletal Class II malocclusion. Furthermore, the increase in the volume of the oropharyngeal airway following the removable functional appliance treatment was more than that observed after fixed functional appliance treatment in growing patients. For patients with skeletal Class III malocclusion, who underwent the bimaxillary orthognathic surgery, resulted in no change in the dimensions of the oropharyngeal airway.ConclusionGrowing patients who receive removable functional appliance treatment have a more favorable long-term prognosis with regard to the oropharyngeal airway when compared with those who receive fixed functional appliance. Alternatively, in patients aged from (18–22) years with skeletal class III malocclusion Bimaxillary orthognathic surgery was found to be the recomended and superior method of treatment.     

Treatment of Class III malocclusions in the Alexander discipline

In the diagnosis and treatment planning of Class III malocclusions, a distinction must be made between pseudo- and true Class III skeletal patterns. The optimal time to initiate treatment is an important consideration. The Alexander Discipline treatment mechanics includes the face mask, chin cap, Class III elastics, and/or lip bumper and rapid palatal expansion. In the nongrowing patient, surgical options are used. The clinical treatment of two patients are presented.