889 resultados para Biofilme dentário
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Pós-graduação em Microbiologia Agropecuária - FCAV
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Objetives: The aim of this study was to verify the anticariogenic effect of acidulate solutions with low NaF concentration, using pH-cycling model and bovine enamel. Material and Methods: Enamel blocks were submitted to the surface microhardness (SMH) test and randomly divided in 12 experimental and one placebo groups. The blocks were submitted to pH cycling for 7 days, with daily applications once/day of 0.05% NaF and 0.1% NaF and twice/day of 0.02% NaF solutions. Four different pH: 4.0, 5.0, 6.0 and 7.0 were used. Next, SMH test was again used to determine the surface microhardness percentage change (%SMH). Data obtained for %SMH were homogeneous and passed through variance analyses and Tukey's test (5%) as far as fluoride concentrations and pH. Results: The results showed that pH influenced %SMH in 0.02% NaF and 0.05% NaF solutions with pH 4.0, which had less mineral loss compared to pH 7.0 (p<0.05). The 0.02% NaF - pH 4.0, and 0.05% NaF – pH 7.0 groups showed similar results (p>0.05). A dose-response relationship was observed among the tested solutions, with better anticariogenic effect for the 0.1% NaF solution. Conclusion: The results suggest that the addition of citric acid to acidulate mouth rinses reduce mineral loss.
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The aim of this study was to compare temperature increases produced by a well-known equipment, the high-speed handpieces, with a relatively new instrument, the Er:YAG laser (350 mJ/10 Hz). Thirty-five bovine mandibular incisors, which were reduced to an enamel/dentin thickness of 2,5 mm, were used. Cavity preparation was done till a depth of 2, 5 mm. A thermocouple was placed to read the temperature inside of the pulp chamber. Analysis was performed in these groups: I - high-speed handpiece without water-cooling (n=10); II - high-speed handpiece with water-cooling (n=10); III - Er:YAG laser without water-cooling (n=5); IV- Er:YAG laser with water-cooling (n=10) Group III had only 5 teeth because it was impossible to properly make the cavity preparations by the laser equipment without water cooling. The temperature increases were recorded in a computer linked to the thermocouples and the data of the groups I, II and IV were submitted to Dunn's multiple comparison test (p<0,05). The medium temperature increases were: 11,64ºC for group I, 0,96ºC for group II, 40,86ºC for group III and 2,9°C for group IV. There were no statistical differences between groups lI and IV, and these were different from group I. The cavity preparations made by the high-speed and the laser equipment generated very similar heat increases under water-cooling. The water-cooling is essential to avoid aggressive temperature increases, both when using the high-speed and the laser equipment, and with laser it is especially necessary for ablation of enamel
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Pós-graduação em Biopatologia Bucal - ICT
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An experimental study was undertaken in arder to find out lhe behavior of the required force to yield dislodgement of circumierential clasps of removable partial dentures ou two groups of samples. 1 with retentive terminais engaging and acting ou enamel 2 with retentive terminais engaging on enamel and acting on composite resm With this aim a device was designed based on a sewing machine (brand name Elgin) that could repeatedly simulate lhe introduction-removal movement of circunferencial clasps ou the samples. ln addiction the device had a platform to sustain the samples and permit measurements, a cycle counter and a dynamometer. The samples were constructed by inclusion in dental stone of extracted natural molar teeth whose retentive areas were ou natural enamel or composite resin addictions.The clasps were fabricated from wax ups of resin and wax and were cast with chromium cobalt alloy. The composite resin used was one of the last generation, monomodal type, photopolymerized and binded to the enamel by the acid etching technique. Tests were carried out in aqueous enviroment. Is was established a maximum of 5.000 cycles for each of the samples. Observatins were made from 100 to 100 cycles until 2.000 and from 200 to 200 cycles to 5.000. Results showed that variations in the amount of the required force for dislodgement of the clasps from the samples during the test periods had no significancy eather to those with retentive areas on the enamel or to those with retentive fabricated with addictions of composite resin
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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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 evaluate the mean of alveolar bone loss (%) in radiographies of patients referred to specialist for periodontal treatment. Full mouth series of periapical radiographies (paralelism technique) were used. A total of 9808 proximal surfaces in 4804 teeth of 213 patients (90 males and 123 females), mean age, 44.3 years, were assessed. The alveolar bone loss was measured in relation to root lenght expressed as an average similar to Schei 's technique (1959) without the use of ruler. The references used were the distances cement-enamel juntion (CEJ) - alveolar crest (AC) and CEJ- dental apex taken with a digimatic caliper. The results showed that the mean values of alveolar bone loss (%ABL) was 22.39%. Men showed higher mean values of %ABL than women; the %ABL increased with the age, but the difference among age groups was no statistical significant (p>0.05); the mean values of %ABL of distal surfaces was higher than mesial surfaces (p<0.01), ríght quadrants exhibited higher %ABL values than left quadrants (p<0.01); maxillary sites showed mean values of %ABL higher than mandibular sites; the highest mean values of %ABL was found in molar group, followed by incisor groups, and premolar group; the canine group exhibited lower mean values of %ABL; the differences among the groups was considered statitistically significant (p<0.01). lt was suggested the usage of this technique in the dentistry offices and radiological services for the patient 's documentation and assortment and for later comparison about alveolar bone level
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Pós-graduação em Odontologia Restauradora - ICT
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Objective: to evaluated the effect of treating root-adhered necrotic periodontal ligament (PDL) with citric acid on the healing process in delayed rat tooth replantation. Material and Methods: Forty Wistar rats, assigned to 4 groups (n=10), had their upper right incisor extracted and kept dry on a workbench. For Group I (control), the teeth were replanted after a 5 min extra-alveolar time. For the other groups, replantation was hydroxide-based paste and the teeth were replanted with no root surface treatment. In Group III, the teeth were immersed in citric acid (pH 1) for replanted. In Group IV, instead of the immersion, the roots were scrubbed with gauze soaked in citric acid and the teeth were replanted. The animals difference (p > 0.05) was found among the groups regarding the areas difference (p < 0.05) between the control group and Group IV regarding ankylosis. The control group showed the least replacement resorption percent means compared to the other groups (p < 0.05). The root structure was more affected by replacement resorption and ankylosis in Group IV statistically (p > 0.05). Conclusion: the treatment of root surface-adhered necrotic periodontal ligament with citric acid was not able to prevent the delayed rat tooth replantation.
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Objective: to evaluated the effect of treating root-adhered necrotic periodontal ligament (PDL) with citric acid on the healing process in delayed rat tooth replantation. Material and Methods: Forty Wistar rats, assigned to 4 groups (n=10), had their upper right incisor extracted and kept dry on a workbench. For Group I (control), the teeth were replanted after a 5 min extra-alveolar time. For the other groups, replantation was done after 60 min. In Group II, the root canals were filled with a calcium hydroxide-based paste and the teeth were replanted with no root surface treatment. In Group III, the teeth were immersed in citric acid (pH 1) for 3 min, the canals were filled with calcium hydroxide and the teeth were replanted. In Group IV, instead of the immersion, the roots were scrubbed with gauze soaked in citric acid and the teeth were replanted. The animals were sacrificed 60 days postoperatively. Results: Regarding replacement resorption, there was statistically significant difference (p < 0.05) between the control group and the other three groups. No statistically significant difference (p > 0.05) was found among the groups regarding the areas of inflammatory resorption. There was also a statistically significant difference (p < 0.05) between the control group and Group IV regarding ankylosis. The control group showed the least replacement resorption percent means compared to the other groups (p < 0.05). The root structure was more affected by replacement resorption and ankylosis in Group IV compared to the Groups II and III, but this difference was not significant statistically (p > 0.05). Conclusion: the treatment of root surface-adhered necrotic periodontal ligament with citric acid was not able to prevent the occurrence of ankylosis, root resorption and inflammatory resorption in delayed rat tooth replantation.