SciCombinator

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Concept: Oral and maxillofacial surgery

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Abstract Objective: To compare the root development and the growth rate of the mandibular third molar (M3 inf) in individuals where the M3 inf erupted vs individuals exhibiting M3 inf impaction. Materials and Methods: Serial standardized intraoral radiographs (Eggen technique) were taken annually of the mandibular third molar region from 132 subjects (71 male and 61 female) from 15 to 20 years of age. Based on the films, 264 lower third molars were classified into an eruption and an impaction group. Root development was recorded according to a quantitative method described by Haavikko (1970), and the eruption status was analyzed using logistic regression. Results: In total, 155 (59%) of the M3 inf erupted, and 109 (41%) were impacted at age 20. In 44 (33%) patients both M3 inf were impacted, in 21 (16%) patients one tooth was erupted and the contralateral tooth impacted, and in 67 (51%) patients both M3 inf were erupted. The more mature a tooth was at age 15, the higher was the probability of eruption (odds ratio: 3.89, P < .001). The growth rate of the root development stage was statistically significantly associated with the probability of eruption (odds ratio: 10.50, P  =  .041). Conclusions: Delayed mandibular third molar root development is associated with impaction. Radiographs taken at age 15 may predict the risk of impaction and thereby guide decision making for the orthodontist or the oral and maxillofacial surgeon.

Concepts: Logit, Decision theory, Teeth, Molar, Oral and maxillofacial surgery, Wisdom tooth, Mandibular third molar

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The aim of this study was to identify the relative risk of damage to the inferior dental (ID) and lingual nerves in patients undergoing lower third molar removal.

Concepts: Teeth, Oral and maxillofacial surgery, Tongue, Lingual nerve, Inferior alveolar nerve, Wisdom teeth

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Background: To date, very few experimental studies have addressed the effect of bone drilling technique and sequence on dental implant osseointegration. In this study, we hypothesized that there would be no differences in osseointegration when reducing the number of drills for osteotomy compared to the conventional drilling protocols. Methods: Seventy-two implants (diameter 3.75 mm and diameter 4.2 mm, n=36 for each diameter) were bilaterally placed in the tibia of 18 beagles for 1, 3, and 5 weeks. Half of the implants of each diameter were placed using a simplified drilling procedure (pilot and final drill) and the other half were placed using a conventional drilling procedure (all drills in sequence). The retrieved samples were subjected to histologic/histomorphometric evaluation. Results: Histology showed that new bone formed around the implant and inflammation or bone resorption was not evident for both groups. Histomorphometrically, the simplified group presented significantly higher bone-to-implant contact and bone area fraction occupancy as compared to the conventional group after 1 week, however, no differences were detected at 3 and 5 weeks. Conclusion: It can be suggested that bone responses to the implant with the simplified protocol is comparable to the conventional protocol.

Concepts: Implants, Prosthetics, Drill, Dental implant, Titanium, Oral and maxillofacial surgery, Osseointegration, Per-Ingvar Brånemark

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This study reports the case of a patient with a severely resorbed mandible who was treated without a bone graft, using short implants, internal rigid fixation, rhBMP-2 and β-tricalcium phosphate. A 76-year-old woman, with a severely resorbed mandible (less than 3mm), reported a history of nearly 25years of complete edentulism and consecutive treatment failures, with total bilateral exposed inferior alveolar nerves and complete bone resorption of the inferior border in some areas. The treatment of choice was the placement of a 2.0mm thick unilock bone plate (MatrixMandible, Synthes Maxillofacial, Paoli, PA, USA), to reinforce the mandible. Eight short implants with a regular platform (Nobel Biocare, Goteborg, Sweden) were placed: three on the external oblique line on both sides and two on the symphysis. In order to augment mandible height and coat the exposed thread of the anterior implants, rhBMP-2 (Infuse Bone, Meditronic Sofamor Danek, Memphis, TN, USA) and β-tricalcium phosphate (Cerasorb; Curasan, Kleinostheim, Germany) were used. Four 1.3mmL miniplates were placed to support the graft. 14months after surgery, the patient was satisfied and had excellent function without complications.

Concepts: Bone, Surgery, Bone resorption, Sweden, Dental implant, Oral and maxillofacial surgery, Abdominal external oblique muscle, Nobel Biocare

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Sialolithiasis is a benign pathology that occurs most frequently in the submandibular salivary gland due to its anatomic features. Depending on the size and degree of calcification, a sialolith can be visible in radiographic examinations. Patients commonly experience pain and/or edema when the ducts are obstructed. The authors report two cases of sialolithiasis of the submandibular gland after searching for the source of swelling in the submandibular region. The diagnosis was confirmed by clinical and tomographic examinations. Despite the considerable size of the sialoliths, treatment consisted of the removal of the calcified mass using an intraoral surgical approach. The prognosis is often good and there is generally no recurrence of the condition.

Concepts: Physician, Medical diagnosis, Autonomic nervous system, Oral and maxillofacial surgery, Parotid gland, Salivary gland, Submandibular gland, Sublingual gland

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Abstract Introduction: Individual planning of complex maxillofacial corrections may require 3D models which can be manufactured based on DICOM datasets. The gold standard for image acquisition is still high-resolution multi-slice computed tomography (MSCT). However, appropriate datasets for model fabrication can be acquired by modern Cone-Beam CT (CBCT) devices that have been developed specifically for maxillofacial imaging. The clinical utility of individual models fabricated on the basis of CBCT datasets was assessed. Methods: In five patients affected by different deficiencies of the maxillofacial skeleton, preoperative imaging was performed with ILUMA CBCT. Segmentation of hard tissues was performed manually by thresholding. Corresponding STL datasets were created and exported to an industrial service provider (Alphaform, Munich, Germany) specializing in rapid prototyping, and 3D models were fabricated by the selective laser sintering (SLS) technique. For variance analysis, landmark measurements were performed on both virtual and 3D models. Subsequently, maxillofacial surgery was performed according to the model-based planning. Results: All CBCT-based DICOM datasets could be used for individual model fabrication. Detailed reproduction of individual anatomy was achieved and a topographic survey showed no relevant aberrance between the virtual and real models. The CBCT-based 3D models were therefore used for planning and transfer of different maxillofacial procedures. Conclusions: CBCT-based datasets can be used for the fabrication of surgical 3D models if the correct threshold is set. Preoperative workflow and patient comfort is improved in terms of the fast-track concept by using this “in-house” imaging technique.

Concepts: Surgery, Reconstructive surgery, Dentistry, Oral and maxillofacial surgery, Microsurgery, Rapid prototyping, Selective laser sintering, Craniofacial surgery

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Objectives. We sought to determine Maryland adults' knowledge, understanding, opinions, and practices with respect to prevention and early detection of dental caries. Methods. We conducted a statewide random-digit-dialing, computer-assisted telephone survey in 2010 among 770 adults who had a child aged 6 years or younger living in their home. A traditional random-digit sample and a targeted low-income sample were included. Analyses included frequencies, percentages, the χ(2) test, and multivariate logistic regression. Results. Respondents' overall level of knowledge about preventing dental caries was low. Those with higher levels of education were more likely to have correct information regarding prevention and early detection of dental caries. Nearly all respondents (97.9%) reported that they were aware of fluoride, but only 57.8% knew its purpose. More than one third (35.1%) of the respondents were not aware of dental sealants. Those with lower levels of education were significantly less likely to drink tap water, as were their children, and significantly less likely to have had a dental appointment in the preceding past 12 months. Conclusions. Our results demonstrate the need to increase oral health literacy regarding caries prevention and early detection. (Am J Public Health. Published online ahead of print April 18, 2013: e1-e8. doi:10.2105/AJPH.2012.301038).

Concepts: Dental caries, Dental implant, Dentistry, Oral and maxillofacial surgery, Dental sealant, Preventive medicine, Halitosis, Pierre Fauchard

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Treacher Collins syndrome is a disorder characterized by various congenital soft tissue anomalies involving hypoplasia of the zygoma, maxilla, and mandible. A variety of treatments have been reported to date. These treatments can be classified into 2 major types. The first type involves osteotomy for hard tissue such as the zygoma and mandible. The second type involves plastic surgery using bone grafting in the malar region and soft tissue repair of eyelid deformities. We devised a new treatment to comprehensively correct hard and soft tissue deformities in the upper half of the face of Treacher Collins patients. The aim was to “change facial features and make it difficult to tell that the patients have this disorder.” This innovative treatment strategy consists of 3 stages: (1) placement of dermal fat graft from the lower eyelid to the malar subcutaneous area, (2) custom-made synthetic zygomatic bone grafting, and (3) Z-plasty flap transposition from the upper to the lower eyelid and superior repositioning and fixation of the lateral canthal tendon using a Mitek anchor system. This method was used on 4 patients with Treacher Collins syndrome who had moderate to severe hypoplasia of the zygomas and the lower eyelids. Facial features of these patients were markedly improved and very good results were obtained. There were no major complications intraoperatively or postoperatively in any of the patients during the series of treatments. In synthetic bone grafting in the second stage, the implant in some patients was in the way of the infraorbital nerve. Thus, the nerve was detached and then sutured under the microscope. Postoperatively, patients had almost full restoration of sensory nerve torpor within 5 to 6 months. We devised a 3-stage treatment to “change facial features” of patients with hypoplasia of the upper half of the face due to Treacher Collins syndrome. The treatment protocol provided a very effective way to treat deformities of the upper half of the face in patients with Treacher Collins syndrome.

Concepts: Syndromes, Oral and maxillofacial surgery, Eyelid, Maxilla, Levator palpebrae superioris muscle, Treacher Collins syndrome, Zygomatic bone

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The aim of this study was to investigate the treatment of Kümmell’s disease with neurological deficits and to determine whether intravertebral clefts are a pathognomonic sign of Kümmell’s disease. A total of 17 patients who had initially been diagnosed with Kümmell’s disease were admitted, one patient was excluded from this study. Posterior decompression and vertebroplasty for the affected vertebrae were conducted. Pedicle screw fixation and posterolateral bone grafts were performed one level above and one level below the affected vertebrae. Vertebral tissue was extracted for histopathological examination. The mean time of follow-up was 22 months (range, 18 to 42 months). The anterior and middle vertebral heights were measured on standing lateral radiographs prior to surgery, one day postoperatively and at final follow-up. The Cobb angle, the visual analog scale (VAS) and the Frankel classification were used to evaluate the effects of the surgery. The VAS, anterior and middle vertebral heights and the Cobb angle were improved significantly one day postoperatively and at the final follow-up compared with the preoperative examinations (P<0.05). No significant differences were observed between the one-day postoperative results and those at final follow-up (P>0.05). The neurological function of all patients was improved by at least one Frankel grade. All patients in this study exhibited intravertebral clefts, and postoperative pathology revealed bone necrosis. One patient (not included in this study) showed an intravertebral cleft, but the pathology report indicated a non-Hodgkin’s lymphoma. The intravertebral cleft sign is not pathognomonic of Kümmell’s disease. Posterior decompression with short-segment fixation and fusion combined with vertebroplasty is an effective treatment for Kümmell’s disease with neurological deficits.

Concepts: Medicine, Pathology, Hospital, Surgery, Histopathology, Skull, Intervertebral disc, Oral and maxillofacial surgery

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Alveolar distraction osteogenesis (ADO), a novel bone augmentation technique, is gaining acceptance in restoring the vertical bone discrepancy between the transplanted graft and the residual alveolar bone after mandibular reconstruction. This case series presents the outcomes of ADO in fibula-reconstructed mandibles rehabilitated with dental implants, with an emphasis on clinical indications, surgical protocol, clinical outcomes, histologic evidence, and complications.

Concepts: Implants, Dental implant, Dentistry, Oral and maxillofacial surgery, Osseointegration, CAD/CAM Dentistry