989 resultados para Dental Enamel Solubility


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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)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Disorders localized to the musculoskeletal system are a common problem among dental personnel. This study has the aim of surveying epidemiological studies reporting positive associations between dental practice and musculoskeletal disorders (MSKDs). The focus was to evaluate the size of reported risk increase and the extent to what alternative causal explanations were considered. Reports with significant links (p value .05) were systematically selected from 2 electronic databases. Twenty-five studies were identified. Risk measures were reported in 8 studies, and all of them presented weak associations. The impact of at least 1 competing explanations was analyzed in 32% of studies, but adjustment was considered not adequate in half of them. The evidence on dentistry as a profession with potential risk for development of MSKDs remains questionable. Further research is needed to more carefully elucidate the risk and the impact of MSKDs in this particular occupational group.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Aim:To examine how much final-year undergraduate dental students know about postural dental ergonomic requirements, and how well they apply these requirements clinically.Background:Dentists are vulnerable to diverse mechanical (e.g. postural) and non-mechanical occupational risks.Materials and Methods:Eight postural requirements found in normalising documents were identified, reproduced, photographed, and analysed to develop a test of visual perception (TVP). Photographs of the 69 participating students were taken during their clinical care to ascertain ergonomics compliance, after which the students were administered the TVP. Pearson's test was used to correlate the level of knowledge (TVP) and its clinical application (photographic analysis) among the 552 observations made for each test (total of 1104 observations).Results:65.7% of the TVP questions were answered correctly and 35% of the photographic cases were in compliance with ergonomic requirements (+ 0.67, P < 0.0001).Conclusion:The knowledge of ergonomics postural requirements and their clinical application among the dental students surveyed were not satisfactory. The reasons for the learning difficulties encountered by the students should be identified to improve the learning process. The didactic use of digital images in this study may help in this endeavour.

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This in vitro study evaluated the effect of erosive pH cycling on the percentage of surface micro-hardness change (%SMHC) and wear of different restorative materials and bovine enamel restored with these materials. Eighty enamel specimens were randomly divided into eight groups according to the restorative materials and immersion media used: GI/GV-resin-modifled glass-ionomer, GII/GVI-conventional glass-ionomer, GIII/GVII-resin composite and GIV/GVIII-amalgam. Over a period of seven days, groups GI to GIV were immersed in a cola drink (ERO) for 5 minutes, 3x/day and kept in artificial saliva between erosive cycles. Groups GV to GVIII were immersed in artificial saliva (SAL) throughout the entire experimental period (control). Data were tested for significant differences using ANOVA and Tukey's tests (p < 0.05). For %SMHC, considering the restorative materials, no significant differences were detected among the materials and immersion media. Mean wear was higher for the resin modified glass ionomer cement when compared to conventional cement, but those materials did not significantly differ from the others. For enamel analyses, erosive pH cycling promoted higher wear and %SMHC compared to saliva. There were no significant differences in wear and %SMHC of enamel around the different restorative materials, regardless of the distance from the restorative material (50, 150 or 300 mu m). In conclusion, there were only subtle differences among the materials, and these differences were not able to protect the surrounding enamel from erosion.

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Reimplantation of primary teeth has been the subject of various clinical and histological studies, but very little is known about the effect of this treatment on primary teeth. The aim of the present study was to histologically evaluate the biological response of dog primary teeth after immediate reimplantation. Twelve dogs were divided into two groups according to postoperative time: 1 week and 3 weeks. Twenty-one upper and lower intermediate incisors were extracted and submitted to endodontic treatment, reimplantation and splinting. The 21 homologous teeth not submitted to treatment served as controls. The animals were killed after the respective experimental periods, and the obtained specimens were processed for histological analysis. Most dogs of the 1-week group exhibited the following alterations: gingival epithelium was inserted in the cemento-enamel junction, with a small number of chronic inflammatory cells being observed in the gingival corium; the periodontal ligament was partially reestablished, with a more expressive chronic inflammatory infiltrate being observed in the apical third; small root resorption was observed on the palatine/lingual side in the apical third. In contrast, in 3-week animals, gingival epithelial insertion was predominantly absent on the buccal side, and a moderate chronic inflammatory infiltrate was present; the periodontal ligament generally showed no bone-cementum reinsertion especially on the palatine/lingual side, with an expressive inflammatory infiltrate in the apical region, and large root resorption was mainly observed on the palatine and lingual sides. In conclusion, reimplantation causes histological alterations in the tooth and its supporting periodontal structures that suggest the impossibility of its maintenance.

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The effect of mouth rinses containing fluoride (100 mu g/ml) and sodium trimetaphosphate (TMP) on enamel erosion was evaluated in vitro. Bovine enamel blocks were subjected to erosive challenges 4 times per day for 5 min, followed by treatment with placebo, 225 mu g F/ml, 100 mu g F/ml, 100 mu g F/ml and TMP (0.2, 0.4 and 0.6%) solutions (30 s) and storage in artificial saliva, over a duration of 5 days. TMP groups showed lower enamel wear than fluoride-only and placebo groups (p < 0.05). Addition of TMP at a TMP:NaF molar proportion between 1.24:1 and 3.72:1 to a solution containing 100 mu g F/ml presented a greater protective effect under erosive conditions than a solution containing 225 mu g F/ml, in the absence of TMP. Copyright (C) 2011 S. Karger AG, Basel

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This article reports a longitudinal follow-up of a 15-month-old child with dental trauma resulting from an attack by a dog. The injury consisted of laceration of the facial tissues and loss of the upper central deciduous incisors, in addition to loss of bone tissue in the same area. A malformation of the crown of the right central permanent incisor and complete change of the shape of the left central permanent incisor were observed. The etiological factors of childhood injuries as well as the importance of dental emergency care are discussed and the 14-year clinical and radiographic follow up of the case is presented.

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Objectives: This study aimed to verify the dental caries prevalence in Baixo Guandu, the first Brazilian city to fluoridate its public water supplies; to compare the findings with the data from the national survey; and also to compare the prevalence in the 12-year-old age group with the data obtained before the beginning of the fluoridation. Methods: All the lifetime residents aged 5, 12, 15 to 19, and 35 to 44 years old were clinically examined (World Health Organization). Results: The means of dmft/DMFT were lower than in the Brazilian population living in fluoridated communities. The DMFT Index in 12-year-old residents decreased between 1953 and 2005 from 8.61 to 1.55. Conclusions: The addition of fluoride to public water supplies was an important ally in the improvement of the oral health of Baixo Guandu inhabitants.

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Background: Prune belly syndrome is a rare condition produced by an early mesodermal defect that causes abdominal abnormalities. However, the literature indicates that disturbances related to ectodermal development may also be present. This is the first case report in the literature to suggest that dental abnormalities are part of the broad spectrum of clinical features of prune belly syndrome. Because the syndrome causes many serious medical problems, early diagnosis of abnormalities involving the primary and permanent dentitions are encouraged.Case presentation: The authors report the clinical case of a 4-year-old Caucasian boy with prune belly syndrome. In addition to the triad of abdominal muscle deficiency, abnormalities of the gastrointestinal and urinary tracts, and cryptorchidism, a geminated mandibular right central incisor, agenesis of a mandibular permanent left incisor, and congenitally missing primary teeth (namely, the mandibular right and left lateral incisors) were noted.Conclusion: This original case report about prune belly syndrome highlights the possibility that dental abnormalities are a part of the broad spectrum of clinical features of the syndrome. Therefore, an accurate intra-oral clinical examination and radiographic evaluation are required for patients with this syndrome in order to provide an early diagnosis of abnormalities involving the primary and permanent dentitions.

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Objectives: the purpose of this study was to investigate the penetration of a conventional adhesive material into enamel bleached with 16% carbamide peroxide and 38% hydrogen peroxide using optical light microscopy.Methods: Extracted human teeth were randomly divided into eight experimental groups with six specimens each, according to the bleaching material and time interval after bleaching and before the bonding procedure. Groups were designated as follows: control group, restorations in unbleached teeth; restorations performed immediately after bleaching; restorations performed 7 days after bleaching; restorations performed 14 days after bleaching; and restorations performed 30 days after bleaching. The length of resin tags was measured with an Axiophot photomicroscope at 400x magnification for the calculation of the proportion of tags of study groups compared to the respective control groups. Analysis of variance was applied for comparison between groups; data were transformed into arcsine (p < 0.05).Results: the specimens of experimental groups, in which restorations were performed 7, 14, and 30 days after bleaching, showed better penetration of adhesive material into enamel than specimens restored immediately after bleaching. There was no statistically significant difference between the bleaching materials employed or in the interaction between bleaching agent and time interval.Conclusions: This suggests that a time interval of at least 7 days should be allowed between enamel bleaching and placement of adhesive bonding agents for accomplishment of composite resin restorations.

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This study evaluated the microtensile bond strength test (mu T), micromorphology of resin-enamel interface (RET) and etching patterns (EP) promoted by the etch-and-rinse adhesive, Prime&Bond NT (PB), and two self-etching adhesives, Clearfil SE Bond (SE) and Adper Prompt L-Pop (APR), to ground bovine enamel surfaces' when applied at temperatures of 5 degrees C (C), 40 degrees C (H) and 20 degrees C (R). Materials and Methods. Sixty-three bovine incisors were randomly divided into nine experimental groups (n=7) according to adhesive systems and temperatures. The buccal enamel surfaces were flattened with 600-grit SiC paper and abraded with a diamond bur under water-cooling. The adhesive systems were applied according to the manufacturer's instructions. After the restorative procedures, the specimens were sectioned into five slabs. Four slabs were prepared for mu T and one for interface analysis. For etching pattern analysis, the remaining 16 bovine enamel fragments were used (n=2). The adhesives were applied and the surfaces were rinsed with organic solvents after application. The specimens for RET and EP analysis were prepared for SEM analysis. Results. No significant differences among the adhesives were found at R temperature. However, at 5 degrees C, PB and APR presented lower bond strength than SE. At H temperature, higher bond strength was observed for PB than for APR and SE. At C and H temperature, formation of the interdiffusion zone was impaired and the treated enamel surfaces presented an undefined EP.