Angle, Tweed, and Moyers classified Class III malocclusions into 3 types: pseudo, dentoalveolar, and skeletal. Clinicians have been trying to identify the best timing to intercept a Class III ...malocclusion that develops as early as the deciduous dentition. With microimplants as skeletal anchorage, orthopedic growth modification became more effective, and it also increased the scope of camouflage orthodontic treatment for patients who were not eligible for orthognathic surgery. However, orthodontic treatment combined with orthognathic surgery remains the only option for patients with a severe skeletal Class III malocclusion or a craniofacial anomaly. Distraction osteogenesis can now be performed intraorally at an earlier age. The surgery-first approach can minimize the length of time that the malocclusion needs to worsen before orthognathic surgery. Finally, the use of computed tomography scans for 3-dimensional diagnosis and treatment planning together with advances in imaging technology can improve the accuracy of surgical movements and the esthetic outcomes for these patients.
Background
One of the most controversial issues in treatment planning of class III malocclusion patients is the choice between orthodontic camouflage and orthognathic surgery. Our aim was to ...delineate diagnostic measures in borderline class III cases for choosing proper treatment.
Methods
The pretreatment lateral cephalograms of 65 patients exhibiting moderate skeletal class III were analyzed. The camouflage group comprised of 36 patients with the mean age of 23.5 (SD 4.8), and the surgery group comprised of 29 patients with the mean age of 24.8 years (SD 3.1). The camouflage treatment consisted of flaring of the upper incisors and retraction of the lower incisors, and the surgical group was corrected by setback of the mandible, maxillary advancement, or bimaxillary surgery. Mann-Whitney
U
test was used to compare the variables between the two groups. Stepwise discriminant analysis was applied to identify the dentoskeletal variables that best separate the groups.
Results
Holdaway H angle and Wits appraisal were able to differentiate between the patients suitable for orthodontic camouflage or surgical treatment. Cases with a Holdaway angle greater than 10.3° and Wits appraisal greater than − 5.8 mm would be treated successfully by camouflage, while those with a Holdaway angle of less than 10.3° and with Wits appraisal less than − 5.8 mm can be treated surgically. Based on this model, 81.5% of our patients were properly classified.
Conclusions
Holdaway H angle and Wits appraisal can be used as a critical diagnostic parameter for determining the treatment modality in class III borderline cases.
This study evaluated the masseter muscle changes after surgical-orthodontic treatment in patients with a skeletal Class III malocclusion using automatic segmentation.
Images of 120 patients with ...skeletal Class III malocclusion were obtained and reconstructed at T0 (pretreatment), T1 (presurgery), and T2 (6-12-month postsurgery). The patients were divided into symmetrical and asymmetrical groups. The volume, major axis length, maximum cross-sectional area, horizontal cross-sectional area 5 mm above the mandibular foramen (CSAF), and orientation were calculated automatically.
In the asymmetrical group, the volume and major axis length on the deviated side were lower than on the nondeviated side at T0, T1, and T2 (P <0.05). There were no significant differences in maximum cross-sectional area and CSAF bilaterally. The orientation was coronally more vertical and sagittally more forward on the deviated side (both P <0.001). In the symmetrical group, there were no significant bilateral differences at T0, T1, and T2. The volume, major axis length, and CSAF decreased, and the coronal orientation was more vertical on the nondeviated side at T2 than at T0 in both groups (P <0.05). The coronal plane orientation was more inclined on the deviated side at T2 than at T0 in the asymmetrical group (P <0.05).
The smaller volume on the deviated side at T2 indicates the need for myofunctional training after surgery. The masseter muscle volume and the cross-sectional area did not recover to the preorthodontic levels. Studies with longer follow-up durations are needed to confirm these findings.
•The automatic masseter muscle segmentation model was used.•The muscle volume remained smaller on the deviated side 6-12 months postsurgery.•Myofunctional training may be required postsurgery on the deviated side.
Bimaxillary surgery is the traditional treatment of choice for correcting class III malocclusion which is reported to cause an alteration of oropharyngeal structures and upper airway narrowing that ...might be a predisposing factor for obstructive sleep apnea (OSA). This study aimed to analyze sleep parameters in class III malocclusion subjects and ascertain the prevalence of snoring or OSA following bimaxillary surgery.A total of 22 patients with Le Fort I osteotomy and mandibular setback for class III malocclusion were prospectively enrolled. All patients received endoscopic examination, cephalometry, 3-dimensional computed tomography (3D-CT), and sleep study twice at 1 month before and 3 months after surgery.The patient population consisted of 5 males and 17 females with a mean body mass index of 22.5 kg/m and mean age of 22.1 years. No patients complained of sleep-related symptoms, and the results of sleep study showed normal values before surgery. Three patients (13%) were newly diagnosed with mild or moderate OSA and 6 patients (27%) showed increased loudness of snoring (over 40 dB) after bimaxillary surgery. According to cephalometric analysis and 3D-CT results, the retropalatal and retroglossal areas were significantly narrowed in class III malocclusion patients, showing snoring and sleep apnea after surgery. In addition, the total volume of the upper airway was considerably reduced following surgery in the same patients.Postoperative narrowing of the upper airway and a reduction of total upper airway volume can be induced, and causes snoring and OSA in class III malocclusion subjects following bimaxillary surgery.
Adult orthodontic treatment involving maxillary transverse deficiency is a challenge for an interdisciplinary team. Surgically assisted rapid palatal expansion to segment the maxilla was once the ...treatment of choice, but the invasiveness, bone deficiency, and gingival recession hindered its acceptance. Corticotomy-assisted rapid maxillary arch expansion with ridge augmentation has the advantage of augmenting alveolar bony housing to accommodate and facilitate tooth movement. This approach was used to correct a severely constricted maxilla with bilateral posterior crossbite and anterior crowding in a 46-year-old man. Treatment time was 14 months. The accelerated arch expansion overcame the crossbite in 7 months, increasing intercanine distance by 5.2 mm and intermolar distance by 9.8 mm. Subsequent implant prosthesis was able to be restored in a functional normal occlusion. Satisfactory and stable clinical outcome was followed for 7 years. Corticotomy-assisted rapid maxillary arch expansion with alveolar bone augmentation is a novel and effective interdisciplinary approach for correcting adult maxillary transverse deficiency. Well controlled prospective clinical trails are warranted for further investigation.
•A new approach for adult maxillary transvers deficiency was demonstrated.•Corticotomy-assisted rapid maxillary arch expansion for adults is possible.•Ridge augmentation may contribute to the long-term stable results.
Introduction Compared to the conventional approach to orthognathic surgery, “surgery first” protocols could be advantageous in terms of shortened treatment times and immediate esthetic improvement. ...However, consensus regarding patient selection, technical protocol, and stability is still lacking. Methods A systematic review of the scientific literature on surgery-first treatment (January 2000 to January 2015) was performed. The PubMED and Cochrane Library databases were accessed. Patient selection criteria, specific surgical-orthodontic protocol, treatment duration, patient and orthodontist satisfaction, and stability of results were compared with a similar population treated conventionally. Results The search yielded 179 publications. The application of strict selection criteria gave the final group of 11 articles. In total, 295 patients were managed with a surgery-first approach. A Class III malocclusion was the most prevalent underlying malocclusion (84.7%). Total treatment duration was shorter in surgery-first patients than in those treated conventionally. There was substantial heterogeneity among articles and high reporting bias regarding the inclusion and exclusion criteria, the orthodontic and surgical protocols, and the stability of results. A meta-analysis of combined data was not possible. Conclusions The surgery-first approach is a new treatment paradigm for the management of dentomaxillofacial deformity. Studies have reported satisfactory outcomes and high acceptance. However, the results should be interpreted with caution because of the wide varieties of study designs and outcome variables, reporting biases, and lack of prospective long-term follow-ups.
Summary
To summarise the skeletal, dental and soft tissue effects of orthopaedic treatment on growing skeletal class III patients compared with a concurrent untreated similar control group and to ...evaluate whether the design of the primary studies may affect the results. A literature search was performed up to the end of February 2016. No restrictions were applied concerning language and appliances. Once the quality score was assessed, a meta‐analysis was performed for the appliances used in more than three studies. A moderator analysis for study design was performed. The level of evidence was evaluated by means of the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) tool. The search resulted in 21 papers. The quality of most of the studies was medium. Each study reported skeletal sagittal improvement and overjet correction. Fourteen studies reported a significant increase in lower facial height. Follow‐up data showed slight relapses in about 15% of patients. Meta‐analyses were performed for the facemask and chin cup. The two appliances were efficient for correcting the sagittal discrepancy, increasing the divergence. In the analysis for study design, the retrospective studies showed a more efficient appliance than RCTs for 6 of 13 variables. The level of evidence was between very low and moderate. There is very low to low evidence that orthopaedic treatment is effective in the correction of Class III skeletal discrepancies and moderate evidence for the correction of the overjet. A common side effect is mandibular clockwise rotation in older subjects.
The aim of this study was to assess the 3-dimensional soft tissue changes in growing Class III patients with maxillary deficiency associated with 2 bone-anchored maxillary protraction protocols in ...relation to an untreated control group of Class III patients.
Growing skeletal Class III patients between the ages of 10 and 14 years participated in this study. In group 1 (n = 10), skeletally anchored facemasks were used with miniplates placed at the zygomatic buttress. In group 2 (n = 10), the patients were treated with Class III elastics extending from infrazygomatic miniplates in the maxilla to symphyseal miniplates in the mandible. Group 3 (n = 10) was an untreated control group. Three-dimensional stereophotogrammetry images were acquired before and after treatment, and then superimposed and analyzed. In addition, lateral cephalometric radiographs were analyzed.
The maxilla moved forward significantly in groups 1 and 2 compared with the untreated control group (group 1, 4.87 mm; group 2, 5.81 mm). The 3-dimensional soft tissue analysis showed significant treatment effects; the major changes were observed in the upper lips, cheeks, and middle of the face, which had a significant positive sagittal displacement in both treatment groups. The lower lip and chin area showed significant negative sagittal changes that indicated that the soft tissue growth in this area was restrained with backward displacement especially in group 1 more than in group 2.
The 2 bone-anchored maxillary protraction protocols effectively improved the Class III concave soft tissue profile.
•We studied 3D soft tissue changes in 2 bone-anchored maxillary protraction protocols.•There were positive sagittal displacements in the upper lips, cheeks, and middle of the face.•The lower lip and chin areas showed significant negative sagittal changes.•The 2 protocols effectively improved the Class III concave soft tissue profile.
Three-dimensional surgical planning for orthognathic surgery is becoming prevalent, with improving outcomes. However, conventional dental casts are still used for evaluations, digital image ...conversion, surgical planning, and occlusal splint production. This study used intraoral scanning for the three-dimensional planning of the final digital occlusion and compared this method with the conventional dental cast approach.
Thirty consecutive patients who underwent two-jaw orthognathic surgery to treat mandibular prognathism and asymmetry were included. Dental casts (control group) and intraoral scans (study group) were collected simultaneously for designing the final dental occlusion. A step-by-step setup of the final digital occlusion was established for the study group. To validate results, the intraoral scanning-based virtual occlusion was superimposed over the dental model-based final digital occlusion for comparison. Intraobserver and interobserver variability were assessed for setting up the final digital occlusion. The fitness of splints fabricated using the conventional and virtual occlusion methods were compared.
The steps for setting up the final digital occlusion were applicable in all cases. The average root-mean-square difference of final occlusion images between the two groups was 0.45 mm, indicating a comparable occlusal relationship. The intraobserver reproducibility and interobserver reliability for setting up the virtual occlusion were satisfactory. Moreover, no significant difference existed in the splint fitness test between the groups.
The proposed intraoral scan and setup process of the final digital occlusion was reliable and accurate. Thus, the method can replace the dental model approach for the three-dimensional planning of orthognathic surgery.
Therapeutic, II.
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