220 resultados para Screw Extruder


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The mini-implant has become a device for anchorage quite widespread and current employee in Orthodontics. The effectiveness of mini-implant is mostly due for its stability primary, however is important to understand about factors that influence the stability. This article presents a review of literature in the database, and as a criterion for inclusion in articles published on the factors related to the stability of mini-implant carried out on humans and animals. The articles was selected according selection criteria related to stability, The factors of mini-implants stability have been described in the literature with scattered scientific information, most of them just as clinical observations. However, these factors of stability can be classified in relation to screw, professional and patient.

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This clinical report describes an adult patient referred for orthodontic treatment with mini-implants as anchorage to correct the root angulation of maxillary lateral incisors. The purpose of this report was to demonstrate the versatility of mini-implants placed in a vertical direction in esthetic areas. During orthodontic treatment, some aspects must be observed to preserve the interim restoration against the occlusal loads to avoid screw fracture. A fixed appliance was placed to correct the position of the maxillary anterior teeth and to complete the treatment. Acceptable esthetics and function were achieved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The aim of this study was to perform a physicochemical and morphological characterization and compare the mechanical behavior of an experimental Ti-Mo alloy to the analogous metallic Ti-based fixation system, for mandibular angle fractures. Twenty-eight polyurethane mandibles were uniformly sectioned on the left angle. These were divided into 4 groups: group Eng 1P, one 2.0-mm plate and 4 screws 6 mm long; group Eng 2P, two 2.0-mm plates, the first fixed with 4 screws 6 mm long and the second with 4 screws 12 mm long. The same groups were created for the Ti-15Mo alloy. Each group was subjected to linear vertical loading at the first molar on the plated side in a mechanical testing unit. Means and standard deviations were compared with respect to statistical significance using ANOVA. The chemical composition of the Ti-15Mo alloy was close to the nominal value. The mapping of Mo and Ti showed a homogeneous distribution. SEM of the screw revealed machining debris. For the plates, only the cpTi plate undergoes a surface treatment. The metallographic analysis reveals granular microstructure, from the thermomechanical trials. A statistically significant difference was found (P < 0.05) when the comparison between both internal fixation techniques was performed. The 2P technique showed better mechanical behavior than 1P.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The objective of this in vitro study was quantify the micro strain development around the internal hexagon implants, varying the type of prosthetic coping. For This reason, three implants of internal hexagon were inserted into one polyurethane block in line placement. Microunit abutments were screwed onto the implants. Tangentially the implants were bonded the strain gauges, two to the center implant. Ten structures, each one containing three copings were cast in Co-Cr alloy, that were divided into groups in the first group, plastic copings were used, and in the second group machined copings were used. The superstructure’s occlusal screws were tightened onto Microunit abutments with 10 Ncm torque, the magnitude of micro strain was recorded. The mean values of each strain gauge of each plastic copings were 363,37 ± 237,66 and the machined copings were 338,12 ± 223,01. The data were analyzed statistically by t- Student test. No statistically significant difference was found between the prosthetic copings (p= 0,867). It was concluded that to internal hexagon implants in line placement, the type of copings presented similar magnitude of micro strain after prosthetic occlusal screw was tightened

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Many structures and mechanical equipment requires a union member, and the screw is one of the most used, the cost is low, it is versatile and easy to find on the market. The resulting pre-load assembly torque associated with the cyclical external load has great influence, so it will be studied carefully. This study analyzed some of these factors, as the format of nuts, and the washer material when they are incompatible with the bolt material can cause a reduction in life of the joint fatigue

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Pós-graduação em Odontologia Restauradora - ICT

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Pós-graduação em Odontologia Restauradora - ICT

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Pós-graduação em Engenharia Mecânica - FEIS

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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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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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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)