Mechanobehavior and mandibular ramus length in different facial phenotypes.

OBJECTIVES: To test the hypotheses that mechanobehavior scores (MBS) were correlated with mandibular ramus lengths (Co-Go) and differed between facial phenotypes. MATERIALS AND METHODS: Subjects gave informed consent to participate. Co-Go (mm), mandibular plane angles (SN-GoGn, °), and three-dimensional anatomy were derived from cephalometric radiography or cone beam computed tomography. Temporomandibular joint (TMJ) energy densities (ED) (mJ/mm3) were measured using dynamic stereometry and duty factors (DF) (%) were measured from electromyography, to calculate MBS (= ED2 × DF,) for each TMJ. Polynomial regressions, K-means cluster analysis, and analysis of variance (ANOVA) with Tukey post-hoc tests were employed. RESULTS: Fifty females and 23 males produced replete data. Polynomial regressions showed MBS were correlated with Co-Go (females, R2 = 0.57; males, R2 = 0.81). Cluster analysis identified three groups (P < .001). Dolichofacial subjects, with shorter normalized Co-Go, clustered into two subgroups with low and high MBS compared to brachyfacial subjects with longer Co-Go. SN-GoGn was significantly larger (P < .03) in the dolichofacial subgroups combined (33.0 ± 5.9°) compared to the brachyfacial group (29.8 ± 5.5°). CONCLUSIONS: MBS correlated with Co-Go within sexes and differed significantly between brachyfacial and dolichofacial subjects.

Effects of mechanical vibrations on maxillary canine retraction and perceived pain: a pilot, single-center, randomized-controlled clinical trial.

The aim of this study was to investigate the effect of mechanical vibratory stimulation on maxillary canine retraction and pain perception in adolescents undergoing full-fixed orthodontic treatment with extraction. A pilot randomized-controlled clinical trial was conducted in one university orthodontic clinic. Twenty-one healthy adolescents who underwent full-fixed orthodontic treatment with maxillary first-premolar extraction were recruited. Subjects were randomly assigned to the experimental group (N = 10) that used a mechanical vibration device (AcceleDent Aura, OrthoAccel Technologies, Inc.) or the control group (N = 11) that did not receive a vibration device. The evaluation timepoints were T0 = day of initial canine retraction; T1 = 4 weeks post-initiation; T2 = 8 weeks post-initiation; and T3 = 12 weeks post-initiation. Three-dimensional palatal landmark superimpositions were made to assess amount of tooth movement (mm) at each visit, monthly rate of tooth movement (mm), and perceived pain levels (VAS scores). The total amount of tooth movement was observed in the control versus experimental groups, respectively, as 1.12 ± 0.22 mm versus 1.39 ± 0.36 mm at 4 weeks (p = 0.058), 2.59 ± 0.37 mm versus 2.49 ± 0.76 mm at 8 weeks (p = 0.702), and 3.54 ± 0.23 mm versus 3.37 ± 1.37 mm at 12 weeks (p = 0.716). The rate of tooth movement was 1.21 ± 0.32 mm/month in the control and 1.12 ± 0.20 mm/month in the experimental groups, which was not statistically significant at any of the timepoints and neither was the level of pain. This study found no statistically significant differences in canine retraction and pain perception between the experimental and control groups. We propose that further optimization of accelerated tooth movement with mechanical vibration devices is necessary.

Obstructive sleep apnea and orthodontics: An American Association of Orthodontists White Paper.

The Board of Trustees of the American Association of Orthodontists asked a panel of medical and dental experts in sleep medicine and dental sleep medicine to create a document designed to offer guidance to practicing orthodontists on the suggested role of the specialty of orthodontics in the management of obstructive sleep apnea. This White Paper presents a summary of the Task Force's findings and recommendations.

3D Airway changes using cone beam computed tomography in patients following mandibular advancement surgery with and without constriction.

OBJECTIVES: The aim of this study was to compare three-dimensional airway changes resulting from mandibular advancement surgery and mandibular advancement surgery with constriction. SETTING AND SAMPLE POPULATION: The University of Michigan School of Dentistry and Medical Center. A total of 42 patients undergoing mandibular advancement with or without simultaneous constriction. MATERIALS AND METHODS: A retrospective airway evaluation of patients undergoing mandibular advancement with or without simultaneous mandibular constriction was performed. Cross-sectional evaluation at standardized locations, minimum cross section and volumetric analysis were performed using Dolphin Imaging TM Version 11.7. RESULTS: Patients undergoing mandibular advancement with or without constriction experienced significant airway increases (P < 0.05). Patients who underwent mandibular advancement only gained nearly twice as much airway volume as mandibular advancement with simultaneous constriction (8.69 mm3 vs 4.3 mm3 ). The largest increase for both groups was observed in the minimum axial area in the oropharynx segment (119.5 mm2 ) and the axial area of the retroglossal region (137.2 mm2 ). CONCLUSIONS: The findings demonstrate mandibular advancement with constriction results in airway enlargement following surgery.

3D Airway changes using CBCT in patients following mandibular setback surgery ± maxillary advancement.

INTRODUCTION: The aim of this study was to determine the 3D airway changes that occur following mandibular setback surgery alone vs bimaxillary surgery in patients with similar skeletal start forms. SETTING AND SAMPLE POPULATION: The University of Michigan School of Dentistry and Medical Center. A total of 85 patients undergoing mandibular setback with or without simultaneous maxillary advancement. MATERIALS AND METHODS: A retrospective evaluation of pre- and post-surgical CBCT scans for patients undergoing mandibular setback surgery alone (14) vs bimaxillary surgery (71) was performed. Cross-sectional evaluation at standardized locations, minimum cross section and volumetric analysis were performed (Dolphin Imaging & Management Solutions). RESULTS: Patients who underwent mandibular setback surgery alone showed a statistically significant average increase of 47.5 mm2 in minimum axial area. Patients who underwent bimaxillary surgery showed a statistically significant increase in airway volume, minimum axial area, location of minimum axial area, and axial area at the retropalatal and retroglossal regions. CONCLUSIONS: The results demonstrate that the mandible can be setback safely without decreasing airway dimensions. In borderline OSA patients, bimaxillary surgery remains the preferred approach due to the larger airway increases observed. Long-term follow-up with polysomnography must be conducted to determine the full functional implications of both procedures.

Three-dimensional treatment planning for maxillary and mandibular segmental surgery for an adult Class III: Where old meets new.

Class III open bite malocclusion can be among the most difficult case types to obtain an excellent occlusal, skeletal, and facial outcome. Treatment options include growth modification, extraction for orthodontic camouflage, and orthognathic surgery. For the most severely affected and non-growing patients, orthognathic surgery is often the most predictable and, in some situations, the only viable way of achieving an optimal result. The risks and benefits of surgical treatment options can occasionally be difficult to assess particularly for providers with limited experience. Two-dimensional surgical predictions can assist but do not permit the third dimension to be visualized. New techniques of computer-aided surgical simulation can enable the surgeon, orthodontist, and patient to better visualize and understand the treatment approach and enable them to make the most effective and efficient treatment related decisions. This case merges knowledge of the full spectrum of historical surgical techniques with the new approach of computer-aided surgical simulation (CASS) to perform complex segmental maxillary and mandibular surgery to obtain an excellent functional and esthetic result.

Asymmetric molar distalization with miniscrews to correct a severe unilateral Class III malocclusion.

Asymmetries are among the most challenging problems in orthodontics. Proper diagnosis is critical to discern first whether the asymmetry is dental or skeletal. If it is dental, one must then determine whether one dental arch or both are at fault. Once diagnosed, the next challenge is determining not only an appropriate treatment plan, but also the appropriate mechanics plan. This aim of this article is to present a patient with a severe asymmetry to emphasize the importance of a problem-based differential diagnosis to develop both a sound treatment plan and a mechanics plan that successfully integrates miniscrews from the start of the process. An 18-year-old woman had a Class III subdivision left malocclusion, an asymmetric lower facial third, and a deviated midline. The treatment plan consisted of asymmetric distalization of the maxillary right and mandibular left posterior dentitions to create space to resolve the deviated midlines, correct the canted occlusal plane, and obtain an ideal occlusion. Active treatment with Clarity ceramic 0.022 × 0.028-in appliances (3M Unitek, Monrovia, Calif), temporary anchorage devices, and a pendulum appliance lasted 22 months. The final result and the 2-year retention records demonstrate that a harmonious facial balance, an attractive smile, ideal occlusal relationships, and a stable outcome were achieved. This case report shows that with proper planning, asymmetric use of temporary anchorage devices in multiple posterior quadrants can be used to obtain molar distalization, and this approach is an effective alternative to dental extraction therapy.

Interdisciplinary treatment for an adult with a unilateral cleft lip and palate.

A young man, age 18 years 4 months, with a concave profile, a skeletal maxillary deficiency, and a severe alveolar cleft with an unesthetic appearance of the maxillary anterior teeth was referred for orthodontic treatment. After a detailed review of his pretreatment records, both surgical and nonsurgical treatment plans were presented to the patient, who opted for a nonsurgical interdisciplinary approach. His complex 3-dimensional malocclusion required palatal expansion, dental extractions, and periodontal and prosthodontic consultations and treatment, in addition to comprehensive orthodontic therapy. MBT (Xinya, HangZhou, China) 0.022 × 0.028-in appliances combined with a mini-implant to enhance the orthodontic anchorage were used to level, align, and establish a Class I relationship. After the orthodontic treatment, a combined restorative and periodontal approach was used to enhance the patient's esthetic and functional outcomes. Both the final result and the 1-year follow-up records demonstrate that the treatment goals of establishing proper occlusion, normal function, a balanced profile, better esthetics, and a stable outcome were achieved. The purpose of this case report is to demonstrate that an interdisciplinary treatment protocol can significantly improve the transverse discrepancies and achieve a satisfactory occlusion with a balanced profile in patients with cleft lip and palate.

Facial soft tissue changes following maxillomandibular advancement for treatment of obstructive sleep apnea.

PURPOSE: The goal of this retrospective study was to evaluate the horizontal and vertical facial soft tissue changes occurring after maxillomandibular advancement (MMA) surgery to treat obstructive sleep apnea (OSA). PATIENTS AND METHODS: The study group comprised 31 consecutive adult patients with OSA who underwent MMA through Le Fort I osteotomy and bilateral sagittal split ramus osteotomies. Adjunctive maxillary procedures, consisting of piriformplasty, anterior nasal spine recontouring, alar base cinch, and V-Y closure of the upper lip, were used for all patients. A "best-fit" templating cephalometric technique was used to assess dentoskeletal movements and corresponding soft tissue changes. RESULTS: Maxillary movements (measured at point A) averaged 8.77 +/- 2.34 mm horizontally and 2.20 +/- 2.42 mm vertically. Mandibular movements (measured at point B) averaged 11.16 +/- 2.56 mm horizontally and 2.25 +/- 3.02 mm vertically. The horizontal upper lip soft tissue-to-hard tissue ratios averaged >0.90:1 (SLS/A, 0.97:1; Ls/U1fac, 0.96:1; Stm(s)/ls, 0.86:1). Upper lip length (Sn-Ls) increased by a clinically insignificant amount (0.37 mm). The nasolabial complex rotated in a counterclockwise rotation, with the nasolabial angle decreasing (3.87 degrees) due primarily to forward movement of the upper lip. Horizontal lower lip and chin soft tissue-to-hard tissue ratios averaged >0.90:1 (Stm(i)/li, 0.90:1; Li/Ii, 0.89:1; Pg'/Pg, 0.92:1; Me'/Me, 0.91:1). CONCLUSIONS: This study demonstrated that MMA in this selected group of OSA patients results in soft tissue movements producing a soft tissue-to-hard tissue ratio of about 0.90:1 for most anatomic sites of the upper lip, lower lip, and chin.

Correction of severe obstructive sleep apnea with bimaxillary transverse distraction osteogenesis and maxillomandibular advancement.

Obstructive sleep apnea (OSA) can be a debilitating, even life-threatening, condition. The most favorable treatment for patients with OSA is multidisciplinary care by a team that represents various dental and medical disciplines. Prescribed therapies might include weight loss, behavior modification, oral appliances, soft tissue surgery, skeletal surgery, or some combination of approaches. When orthognathic surgery has been used, often only the anteroposterior dimension is addressed, and the transverse dimension is overlooked. The treatment presented here demonstrates the important role that transverse expansion of the maxillary and mandibular arches can have for patients with severe OSA. An initial stage of maxillary and mandibular transverse distraction osteogenesis was performed, followed immediately by fixed orthodontic treatment. After appropriate orthodontic alignment, leveling, and coordination, a second surgical stage consisting of maxillary and mandibular advancement was performed. Marked enhancements in occlusion and facial morphology, and a profound improvement in the OSA, were obtained.