228 resultados para pedicle screw
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Immediate reutilization of the expanding action in a case of rapid maxillary expansion surgically assisted. The orthopedic rapid maxillary expansion (RME) and rapid maxillary expansion surgically assisted (RMESA) are conducted with the aim of giving an appropriate jaw, capable of providing a normal occlusion. In extreme cases, where there is a severe atresia, it is necessary to perform an expansion beyond that allowed by the expander, followed by another conventional device or a butterfly expander, when the atresia is in the anterior maxillary region. In this situation, there are two options: wait about 90 days to allow intermaxillary suture restructuring and perform a new RME / RMESA or proceed immediately to the expansion process. Considering the biological cost, financial and clinical time, the procedure of reusing the immediate expander action becomes the technique of choice in these cases, been the operational procedure performed simplified and in just four steps. This work will show a case report where, after accomplishing the RMESA was observed that even after changing the shape of the maxillary arch, the severity of atresia could not be corrected, especially in the anterior region, and more expansion was needed. Aiming to correct the atresia in the anterior maxilla, the technique used was to reuse the immediate expander action through the change of an intraoral screw expander for a conventional butterfly type screw expander.
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Gingival recession is a common deformity that affects a large number of people. This condition is frequently associated with esthetic complains and may lead to dental hypersensitivity. Thus, various surgical procedures have been proposed to provide root coverage. Since the 1950s, free and pedicle gingival grafts have been greatly used for treating gingival recession. However, after the 1985 Miller gingival recession classification, and with the development of other appropriated techniques that use subepithelial connective tissue grafts, gingival recession treatments have resulted in more predictable outcomes, especially with respect to Class I and II sites, i.e., in the absence of interproximal bone loss. This article reported the importance of aesthetical periodontal treatment in the prosthetic rehabilitation of a patient with a class I gingival recession with 3 mm of vertical extension in the superior canine. The treatment plan consisted of root coverage using subepithelial connective tissue graft (SCTG) associated with construction of new prosthesis.
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The sagittal split ramus osteotomy (SSRO) is a surgical technique used widely to treat many congenital and acquired mandibular discrepancies. Stabilization of the osteotomy site and the potential for skeletal relapse after the procedure are still major problems. The aim of this study was to compare the mechanical stability of six methods of rigid fixation in SSRO using a biomechanical test model. Sixty polyurethane replicas of human hemimandibles were divided into six groups. In group I, the osteotomies were fixed with two four-hole titanium miniplates; in group II, with one four-hole miniplate; in group III, with one four-hole miniplate + a bicortical screw; in group IV, with a grid miniplate; in group V, with a four-hole locking miniplate; and in group VI, with a six-hole miniplate. A linear load in the premolar region was applied to the hemimandibles. The resistance forces (N) needed to displace the distal segment by 1, 3, and 5 mm were recorded and the data transmitted from the load cell to a computer. One-way analysis of variance with Tukey's post hoc test was performed to compare the means between groups. For the three displacement conditions, there was a strong tendency for the 2.0-mm plate + screw and the grid plate to have higher values.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Gingival recession is a common deformity that affects a large number of people. This condition is frequently associated with esthetic complains and may lead to dental hypersensitivity. Thus, various surgical procedures have been proposed to provide root coverage. Since the 1950s, free and pedicle gingival grafts have been greatly used for treating gingival recession. However, after the 1985 Miller gingival recession classification, and with the development of other appropriated techniques that use subepithelial connective tissue grafts, gingival recession treatments have resulted in more predictable outcomes, especially with respect to Class I and II sites, i.e., in the absence of interproximal bone loss. This article reported the importance of aesthetical periodontal treatment in the prosthetic rehabilitation of a patient with a class I gingival recession with 3 mm of vertical extension in the superior canine. The treatment plan consisted of root coverage using subepithelial connective tissue graft (SCTG) associated with construction of new prosthesis.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Medicina Veterinária - FCAV
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Odontologia Restauradora - ICT
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Pós-graduação em Odontologia - FOA
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The study of short implants is relevant to the biomechanics of dental implants, and research on crown increase has implications for the daily clinic. The aim of this study was to analyze the biomechanical interactions of a singular implant-supported prosthesis of different crown heights under vertical and oblique force, using the 3-D finite element method. Six 3-D models were designed with Invesalius 3.0, Rhinoceros 3D 4.0, and Solidworks 2010 software. Each model was constructed with a mandibular segment of bone block, including an implant supporting a screwed metal-ceramic crown. The crown height was set at 10, 12.5, and 15 mm. The applied force was 200 N (axial) and 100 N (oblique). We performed an ANOVA statistical test and Tukey tests; p < 0.05 was considered statistically significant. The increase of crown height did not influence the stress distribution on screw prosthetic (p > 0.05) under axial load. However, crown heights of 12.5 and 15 mm caused statistically significant damage to the stress distribution of screws and to the cortical bone (p <0.001) under oblique load. High crown to implant (C/I) ratio harmed microstrain distribution on bone tissue under axial and oblique loads (p < 0.001). Crown increase was a possible deleterious factor to the screws and to the different regions of bone tissue. (C) 2014 Elsevier Ltd. All rights reserved.
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Craniofacial trauma can lead to several complications. The combined fractures of anterior and posterior walls of the frontal bone are almost always followed by lesions in nasofrontal orifices and disruption of nasofrontal ostia or ducts, a significant factor for the development of early and late complications after sinus fractures. This article reports a case of trauma patient, who underwent neurological evaluation and at first showed good general condition. Computed tomography noted fracture of the anterior and posterior walls of the frontal sinus and small foci of pneumocephalus in the cerebral cortex. The patient was monitored periodically and 9 days after trauma showed increased areas of pneumocephalus in prefrontal cortex, cerebrospinal fluid draining, and large dura mater lesion, with signs of necrosis and inflammation (meningitis). The necrotic tissues were removed, and dura mater was repaired through the approximation with resorbable wire polyglactin 910 5-0, oxidized cellulose application, and bonding with human fibrin sealant (fibrinogen, thrombin, and calcium chloride). Sinusectomy, frontal sinus, and nasofrontal duct obliteration with pedicled pericranium flap were performed. Tomographically, a reanatomization was noted in frontal region, and a 12-month follow-up showed no complication. The use of fibrin glue to repair dura mater lacerations, as well as the pedicle pericranium flap for frontal sinus and nasofrontal duct obliteration, is an efficient method for treating fractures of the frontal bone.
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The aim of this study was to evaluate stress distribution in the fixation screws and bone tissue around implants in single-implant supported prostheses with crowns of different heights (10,12.5, 15 mm crown-to-implant ratio 1:1, 1.25:1, 1.5:1, respectively). It was designed using three 3-Dmodels. Each model was developed with a mandibular segment of bone block including an internal hexagon implant supporting a screw-retained, single metalceramic crown. The crown height was set at 10, 12.5, and 15 mm with crown-to-implant ratio of 1:1, 1.25:1, 1.5:1, respectively. The applied forces were 200 N (axial) and 100 N (oblique). The increase of crown height showed differences with the oblique load in some situations. By von Mises'criterion, a high stress area was concentrated at the implant/fixation screw and abutment/implant interfaces at crown-to-implant ratio of 1:1, 1.25:1, 1.5:1, respectively. Using the maxiinum principal criteria, the buccal regions showed higher traction stress intensity, whereas the distal regions showed the largest compressive stress in all models. The increase of C/I ratio must be carefully evaluated by the dentist since the increase of this C/I ratio is proportional to the increase of average stress for both screw fixation (C/I 1:1 to 1:1.25 ratio = 30.1% and C/I 1:1 to 1 :1.5 ratio = 46.3%) and bone tissue (C/I 1:1 to 1:1.25 ratio = 30% and C/I 1:1 to 1:1.5 ratio = 51.5%). (C) 2014 Elsevier B.V. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)