SciCombinator

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Concept: Orthognathic surgery

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Resorbable screw fixation for orthognathic surgery is widely used in oral and maxillofacial surgery and has several advantages. However, surgeons are concerned about using resorbable screws in orthognathic surgery because of possible postoperative complications such as relapse, screw fracture, and infection. The purpose of this study was to evaluate the skeletal stability of bicortical resorbable screw fixation after sagittal split ramus osteotomies for mandibular prognathism.

Concepts: Surgery, Reconstructive surgery, Dentistry, Oral and maxillofacial surgery, American College of Surgeons, Orthodontics, Microsurgery, Orthognathic surgery

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To estimate the prevalence of mandibular asymmetries in orthodontic and orthognathic surgery patients and to investigate demographic and skeletal factors associated with this disharmony.

Concepts: Orthodontics, Orthognathic surgery

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There is considerable controversy in the literature concerning the indications for frenectomy for treating a maxillary diastema and for timing of the procedure. The purpose of this study was to survey pediatric dentists, orthodontists, and oral and maxillofacial surgeons on their opinion of this matter to develop a consensus.

Concepts: Surgery, Physician, Dental implant, Dentistry, Oral and maxillofacial surgery, Orthognathic surgery

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Facial asymmetry can be caused by unilateral condylar hyperplasia. In such cases, it may be difficult to achieve symmetry since there is dentoalveolar compensation on the affected side, and the occlusal cant does not correspond to the frontal mandibular deviation. In the case presented, surgical orthodontic treatment and orthognathic surgery planning was accomplished for a patient with facial asymmetry due to condylar hyperplasia. The surgical plan was devised with particular attention to the severe dentoalveolar compensation. In this case, prior to the two-jaw surgery, the occlusal cant and frontal mandibular plane inclination was corrected through impaction of the left molar region by segmental osteotomy. Facial asymmetry and severe dentoalveolar compensation were successfully corrected after a unilateral segmental osteotomy and two-jaw surgery, resulting in a stable occlusal relationship and facial symmetry as well as good jaw function. Collaboration between the orthodontists and maxillofacial surgeons was essential for the successful treatment of the patient.

Concepts: Surgery, Physician, Dentistry, Oral and maxillofacial surgery, Orthodontics, Asymmetry, Facial symmetry, Orthognathic surgery

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A 43-year-old man sought orthodontic treatment to close anterior diastemas. During the impression procedure for routine documentation, the orthodontic assistant exerted excessive pressure on the metallic tray; 2 days later, the patient reported the detachment of a small piece of mucosa overlying the mylohyoid crest and was referred to a maxillofacial surgeon with a diagnosis of lingual mandibular osteonecrosis. The etiology of bony osteonecrosis is discussed, together with the anatomic variations that can be present in the basal bone and that must be carefully checked before an impression is taken.

Concepts: Surgery, Physician, Dental implant, Dentistry, Oral and maxillofacial surgery, American College of Surgeons, American Dental Association, Orthognathic surgery

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Augmentation reality technology offers virtual information in addition to that of the real environment and thus opens new possibilities in various fields. The medical applications of augmentation reality are generally concentrated on surgery types, including neurosurgery, laparoscopic surgery and plastic surgery. Augmentation reality technology is also widely used in medical education and training. In dentistry, oral and maxillofacial surgery is the primary area of use, where dental implant placement and orthognathic surgery are the most frequent applications. Recent technological advancements are enabling new applications of restorative dentistry, orthodontics and endodontics. This review briefly summarizes the history, definitions, features, and components of augmented reality technology and discusses its applications and future perspectives in dentistry.

Concepts: Surgery, Dental implant, Reconstructive surgery, Dentistry, Oral and maxillofacial surgery, Microsurgery, Surgical specialties, Orthognathic surgery

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Maxillary distraction is increasingly used for the correction of severe maxillary retrusion in patients with cleft lip and palate. However, control of the maxillary movement is difficult, and the need to wear visible distractors for a long period of time causes psychosocial problems. A two-stage surgical approach consisting of maxillary distraction and mandibular setback was developed to overcome these problems. In this study, changes in maxillofacial morphology and velopharyngeal function were examined in 22 patients with cleft lip and palate who underwent this two-stage approach. Lateral cephalograms taken just before the first surgery, immediately after the second surgery, and at completion of the active post-surgical orthodontic treatment were used to examine maxillofacial morphology. Velopharyngeal function was evaluated by speech therapists using a 4-point scale for hypernasality. The average forward movement of the maxilla with surgery at point A was 7.5mm, and the average mandibular setback at pogonion was 8.6mm. The average relapse rate during post-surgical orthodontic treatment was 25.2% for the maxilla and 11.2% for the mandible. After treatment, all patients had positive overjet, and skeletal relapse was covered by tooth movement during postoperative orthodontics. Velopharyngeal function was not changed by surgery. This method can shorten the period during which the distractors have to be worn and reduce the patient burden.

Concepts: Surgery, Mandible, Dentistry, Oral and maxillofacial surgery, Orthodontics, Maxilla, Maxillary nerve, Orthognathic surgery

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This article describes the complex dental treatment of a 43-year-old man with skeletal Class II, mandibular asymmetry, severe brachyfacial pattern, Class II Division 2, canting of the occlusal plane, and an increased curve of Spee. To achieve optimal results, we adopted a multidisciplinary approach to treatment, involving periodontics, oral surgery, orthodontics, maxillofacial surgery, and prosthetics specialists. After periodontal treatment, miniscrews were placed to correct the occlusal plane canting and the excessive curve of Spee with orthodontic treatment. The surgical treatment plan consisted of a bilateral asymmetric sagittal split osteotomy for mandibular advancement and genioplasty. The patient had an infection after the surgery at the site of the right fixation plate, so the plate was removed, and active orthodontic treatment was continued and finished. Mandibular first molar implants and maxillary ceramic crowns using the Digital Smile Design method (Digital Smile Design, Doral, FL) were placed at the end of orthodontic treatment. The patient was satisfied with the treatment results and with his facial and dental appearance, as well as his oral function. The 2-year follow-up pictures show a stable result both esthetically and functionally.

Concepts: Surgery, Dental implant, Dentistry, Oral and maxillofacial surgery, Orthodontics, Microsurgery, Orthognathic surgery, Dentistry branches

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The conventional approach during orthognathic surgery for cleft-related deformities has largely focused on restoration of maxilla retrusion, using the maxillary advancement as a standard treatment objective. However, we thought the maxillary vertical shortening and deficient incisor show could be the additional key elements of cleft-related deformities. Although slight vertical lengthening can be obtained with only maxillary advancement, it would not be enough to obtain satisfactory aesthetical results in terms of the anterior facial height. We hypothesized that vertical deficiency as well as anteroposterior maxillary retrusion exists in cleft-related deformities. Therefore, orthognathic surgery including intentional vertical lengthening and advancement would be better than the conventional simple advancement.

Concepts: Standard, Maxilla, Orthognathic surgery

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Mg-Ca-Zn alloy has been suggested for the application of fixation materials during maxillofacial surgery. We investigated the stability of Mg-Ca-Zn alloy for clinical application during orthognathic surgery. The finite element model for the fixation of sagittal split ramus osteotomy was constructed. In the bicortical screw fixation of the mandible setback condition, the stress distributions of Mg-Ca-Za alloy, polylactic acid polymer, and titanium were evaluated using the virtual model with occlusal loading of 132 N. The deformations of the three different materials of fixation screw were observed according to masticatory force ranging from 132 to 1,000 N. When comparing the stress distribution placed on cortical bone between the polymer and magnesium alloy groups, the magnesium alloy screws could bear more stress, thereby decreasing the stress, which might be distributed to other biologic components, such as the condyle and cortical ramus of the mandible. Deformations of the screws according to functional load were minimal, and the deformation remained <0.21 mm at the initial functional load of the mandible after surgery, regardless of materials used. The biodegradable magnesium alloy screw can bear more stress and decrease the detrimental effect on the stability of sagittal split ramus osteotomy setback surgery.

Concepts: Magnesium, Aluminium, Finite element method, Distribution, Dentistry, Oral and maxillofacial surgery, Bioplastic, Orthognathic surgery