140 resultados para Metalurgia odontologica


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Oral exfoliative cytology (EC) is a rapid and practical complementary test that can be used in the diagnosis of various diseases. The objectives of this study were to assess dentists'knowledge of EC and to disseminate information on the technique. The study included 240 dentists from the city of Anapolis (Goias, Brazil) who answered a questionnaire regarding demographic data and data relating to EC and who then received information on the technique. The data revealed that 26.92% of the dentists did not know about EC. Among those who reported knowledge of EC, 33.91% did not know the procedures for performing the technique, and 85.38% had no experience with EC. In addition, 54.09% of the answers regarding the instrument used to collect the material and 56.82% of the answers concerning suitable fixatives were inappropriate. Although 73.02% of the dentists adequately identified the pathologies for which EC is recommended, it was concluded that the respondents had poor knowledge of EC. There is a need to increase dentists'awareness of this subject and of EC's use in diagnostic practices.

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The aim of this study was to evaluate the resorption process during the repair of autogenous bone grafts with or without coverage by an expanded polytetrafluoroethylene (e-PTFE) membrane in female rats with estrogen deficiency using the immunohistochemical technique. Eighty female rats were randomly divided into two groups (OVX and SHAM). The 40 female rats in the OVX group were subjected to ovariectomy, and the 40 female rats in the SHAM group were subjected to simulated ovariectomy. The two groups were further divided in subgroup E, which was subjected to surgery for placement of autogenous bone graft (ABG), and subgroup ME, in which the ABG was covered with an e-PTFE membrane. The animals were killed at 0, 7, 21,45 and 60 days. The specimens were analyzed using immunohistochemistry for the bone resorption markers RANK, RANK-L and Osteoprotegerin (OPG). A higher remodeling rate was observed at 7 and 21 days after the autogenous bone grafts, when the markers were more intensely expressed. At the final time point, the specimens presented similar characteristics to those observed at the initial time point. The expression of immunohistochemical markers was not altered by the estrogen deficiency. The presence of the e-PTFE membrane delayed the bone resorption process, influencing the immunohistochemical expression of markers.

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Manufacturers offer various prescriptions of preadjusted brackets for use in the "straight-wire" orthodontic technique. However, the need to incorporate bends in the rectangular wires during orthodontic finishing has led to concerns regarding the type of prescription chosen and the credibility of information provided by the manufacturer. The aim of this study was to compare the slot angulations of Roth prescription preadjusted metallic brackets for the maxillary left central incisor and maxillary left canine. For each tooth type, 10 brackets of three commercial brands (GAC, Forestadent and Morelli) were selected. Two individual metal matrices for brackets and tooth positioning were made for each group of teeth. Captured images were obtained by standardized ortho-radial photography with a digital camera. Images were exported and analyzed with the Image J software package. One-way ANOVA and Tukey statistical analyses were performed at the 5% significance level. For brackets of the maxillary left central incisor, differences in mean angulation were observed between the Morelli and GAC groups (p < 0.01) and between the Forestadent and GAC groups (p < 0.01). For brackets of the maxillary left canine, differences in mean angulation were found between the Morelli and GAC groups (p < 0.01) and between the Morelli and Forestadent groups (p < 0.05). In conclusion, despite their same prescription name, the different brands exhibited significantly different angulation measurements.

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The purpose of this study was to analyze the bone repair around commercially pure titanium implants with rough and porous surface, fabricated using powder metallurgy technique, after their insertion in tibiae of rabbits. Seven male rabbits were used. Each animal received 3 porous-surface implants in the left tibia and 3 rough-surface implants in the right tibia. The rabbits were sacrificed 4 weeks after surgery and fragments of the tibiae containing the implants were submitted to histological and histomorphometric analyses to evaluate new bone formation at the implant-bone interface. Means (%) of bone neoformation obtained in the histomorphometric analysis were compared by Student's t-test for paired samples at 5% significance level.. The results of the histological analysis showed that osseointegration occurred for both types of implants with similar quality of bone tissue. The histomorphometric analysis revealed means of new bone formation at implant-bone interface of 79.69 ± 1.00% and 65.05 ± 1.23% for the porous- and rough-surface implants, respectively. Statistically significant difference was observed between the two types of implants with respect to the amount new bone formation (p<0.05). In conclusion, the porous-surface implants contributed to the osseointegration because they provide a larger contact area at implant-bone interface.

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This in vitro study compared the effect of bleaching agents modified by the addition of calcium and/or fluoride and the application of a nano-hydroxyapatite paste after bleaching, on the susceptibility of enamel to erosion. Bovine enamel cylindrical samples (3 mm diameter) were assigned to six groups (n = 20 specimens/group) according to the bleaching agent: no bleaching (C-control), 7.5% hydrogen peroxide gel (HP), HP with 0.5% calcium gluconate (HP+Ca), HP with 0.2% sodium fluoride (HP+F), HP with calcium and fluoride (HP+Ca+F) and HP followed by the application of a nano-hydroxyapatite agent (HP+NanoP). The gels were applied on the enamel surface (1 h) followed by cyclic erosive challenges (Sprite Zero®-2 min), for 14 days. The paste was applied after bleaching for 5 min (HP+NanoP). The enamel surface alteration was measured by contact profilometry (µm) (after 7 and 14 days). C-control (mean ± SD: 2.29 ± 0.37 at 7 days/4.86 ± 0.72 at 14 days) showed significantly lower loss compared to the experimental groups. HP+Ca (3.34 ± 0.37/6.75 ± 1.09) and HP+F (4.49 ± 0.92/7.61 ± 0.90) presented significantly lower enamel loss than HP (4.18 ± 0.50/10.30 ± 1.58) only for 14 days and HP+Ca+F (4.92 ± 1.03/8.12 ± 1.52) showed values similar to the HP+F group. The HP+NanoP (5.51 ± 1.04/9.61 ± 1.21) resulted in enamel loss similar to the HP after 14 days. It was found that 7.5% hydrogen peroxide increased the susceptibility of enamel to erosion. The addition of calcium or fluoride to the bleaching gel reduced the erosion effect, while the nano-hydroxyapatite agent did not provide any protective effect.

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Pós-graduação em Engenharia Mecânica - FEG

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The rehabilitation with mandibular distal extension removable partial dentures (DERPD) is complex and the use of implants has been improving the functioning of this approach. The insertion bony level around of the last support tooth is an aggravating factor, since it can harm the longevity of the treatment. Thus, the aim of this research was to evaluate the displacement tendency of a mandibular DERPD associated to an implant, with different insertion bony levels and different connections between the RPD and the support tooth, by finite element analysis. Eight models were made: MA - DERPD, incisal rest, no bony loss; MB - DERPD, distal plate, no bony loss; MC - DERPD, incisal rest, no bony loss, with implant and ERA system; MD - DERPD, distal plate, no bony loss, with implant and ERA system; ME - DERPD, incisal rest, bony loss; MF - DERPD, distal plate, bony loss; MG - DERPD, incisal rest, bony loss, with implant and ERA system; MH - DERPD, distal plate, bony loss, with implant and ERA system. Loads of 50 N in each peak were applied. Displacement maps were obtained and showed that implant favors this association and the bony loss harms the prognostic of the prosthesis. It is concluded that: the introduction of the implant with ERA system reduced the displacement tendency of the tooth and supporting structures; introduction of distal plate reduced the movement tendency of the support tooth; the decrease of the periodontal support didn't influence significantly the displacement tendency of the models with distal plate distal, but it influenced the models with distal incisal rest.

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The use of computers in dental clinics has brought many benefits to dentist, helping them in various technical, administrative and legal. This study aimed to verify whether dentist, students of the post-graduate course in Orthodontics and Implantodontia of the Brazilian Association of Dentistry (ABO), regional Araçatuba-SP, using computers and digital documentation in clinical practice. They were invited to participate in the study all 60 students enrolled in courses of Orthodontics and Implantodontia of those institutions, in the year 2007 and those who consented (n = 52) answered a questionnaire containing questions open and closed on the subject . As the profile of the participants, 64.5% are male, 51.9% are between 30-39 years of age and 48.1% completed the graduation in the 90th. A 69.3% said they didn't receive any notion of computing during graduation and 67.3% use the computer in the office, mainly for management of the same (34.3%). Regarding the use of electronic record 55.8% reported using this technology, while 44.2% denied. 32.7% do not believe that electronic records that can serve as proof of judicial and 35.7% believe that the electronic records should be archived for 20 years. It follows that most professionals use the computer in the office and also the digital records, but does not feel secure about the legal validity of such documents, unknown, including the appropriate time of its filing.

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Early treatment of functional unilateral posterior crossbite during the mixed dentition is extremely important for contemporary Orthodontics, provides the correct positioning of osseous bases, teeth and temporomadibular joint when the stomatognathic system is in growth and development. These results generally develop into an adequate craniofacial relationship, reducing the necessity for more complex treatments at permanent dentition. The subject of this paper was to report patient 8 years old, diagnosed with functional unilateral posterior crossbite, and was treated by an expander appliance type Quad-helix emphasizing the long-term stability. The malocclusion was corrected in 3 months of active use of the appliance, 3 months for retention purposes and followed up during 7 years post-treatment. The stability in long term of functional unilateral posterior crossbite treated is closely related with early diagnostic, the elimination of the etiological factor associated with a correct appliance and the mechanic of treatment.

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The different kind of appliances for the treatment of posterior crossbite make that the orthodontist assess some criterions for their selection and success for the treatment. The aim of this paper was to compare two methods of treatment of the posterior crossbite by two case reports treated with Quad-helix and removable plate. Concluding that the Quad-helix is the appliance of first choice in relation of the removable plate for the short time of active treatment, the less visits and chair time, the fewer cost of treatment and the smaller cooperation of the patient.

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The number of lawsuits against dental surgeons has increased considerably in the recent years. Probably this is due to a change in the behavior of the patients, from a passive role in the past to a more demanding stance now. A transversal study was carried out to evaluate the point of view of lawyers in Araçatuba, SP, Brazil, about the professional liability of dentist, the major reasons for treatment failure, the dental specialties more involved in legal actions, their attitudes if they were submitted to an unsuccessful dental treatment, their opinion on what the dentist should do when a patient does not accept the treatment provided, and, finally, what a dentist should do when facing a civil liability action. A questionnaire was sent to 318 lawyers, and 151 of them answered it. The results show that for most lawyers an occasional failure in the treatment occurs due to professional incompetence and, in their opinion, the specialty more involved in legal problems is orthodontics (64.7%). Of the lawyers interviewed, 27.0% affirmed they would seek another dentist and also a lawyer, if they were subjected to an unsuccessful dental treatment. For 36.5% of them, the dentist should give further information and explain the reasons why the treatment did not meet the patient's expectations. According to 36.1% of the interviewees the best policy to be adopted by the dentist in case of a civil liability action would be an extra judicial settlement.

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The aim of this study was to evaluate the occlusal condition of 12 year-old children examined by the Oral Health Brazil 2003 Project in Cáceres city. The sample consisted of 170 children, boys and girls, selected at random among 20 schools that took part in this project. It was used for the analysis of the occlusal condition the Dental Aesthetic Index (DAI), as manual of basic epidemic rising in Oral Health extolled by the World Health Organization which describes the occlusal conditions in relation to dentition, space and occlusion of the permanent dentition. It was observed that the prevalence of the normal occlusion and of the malocclusion were, respectively, 21.18% and 78.82%. This last one was present due to the tooth crowding (74.93%), spacing in the incisor segment (23.88%), diastema (17.17%), anterior maxillary misalignment (58.95%) and anterior mandibular (61.19%), excessive overjet (11.94%), negative overjet (4.47%), open bite (1.5%) and molar relationship Class II or III (26.87%). It was concluded that the studied sample presents a high index of factors to compose the malocclusion.

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Miners activity results in a significant volume of waste, which is normally deposited in piles. This paper analyzes the behavior of geotextile barrier to control fine soil runoff in a quarry. Two types of geotextile was investigated in order to evaluate the retention efficiency and deterioration after several use.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)