932 resultados para Ultrasonic toothbrush
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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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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The main purpose of the present study is to integrate a geological and technological investigation of ornamental rocks of the Flores and Jacarandá granites, which are located near the Afonso Bezerra city, in the north central part of the Rio Grande do Norte State. The study area encompasses four litho-stratigrafic units: a Gneiss-Migmatitic Complex(cristalline basement), which is mainly composed of banded gneisses, usually deformed as mylonitic rocks and with several migmatic features, an Augen Gneiss, which occurs as an elongated body that constitutes the Jacarandá granite, a small granite stock, which presents a semi-circular form, named Flores granite, composed of pink, fine to medium coarse rocks, and fine to coarse alluvial sediments, which form extensive areas of large fluvial deposits. The technological characterization of the Flores and Jacarandá granites, carried out through several tests, has as the main purpose the determination of petrographic, physical, and mechanic parameters that allowed the characterization of these rocks. The test followed procedures recommended by Brazilian (ABNT Associação Brasileira de Normas Técnicas) and foreigner institutions (ASTM American Society for Testing and Materials). The petrografhic analysis indicated that the rocks investigated are granite sensu estrictu, summing an average 85-90% modal. The Flores granite is the more felsic rock, which presents mafic content ∼ 10% and monzonitic composition. The Jacarandá granite is an Augen Gneiss rock that presents sienogranitic composition and mafic modal content ∼ 15%. Several technological tests carried out (alterability, physical indices, velocity of ultrasonic wave propagation, uniaxial compression, flection resistence, Amsler desgaste, and resistence to freezing and heating) indicated that parameters and values were identical for both granites investigated. These parameters and values are consistent with the Brazilian and international standards for siliciclastic rocks of ornamental use, as well as other Brazilian ornamental granites. The analysis of all results indicates that both the Flores and Jacarandá granites present good quality, and that they are indicated for ornamental use of revetment interior and exterior of buildings
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Avaliou-se a espessura corneana central de 13 gatos normais com microscópio especular de não-contato Topcon SP-2000P e paquímetro ultra-sônico. Foi observado aumento da espessura corneana mensurada pelo paquímetro ultra-sônico comparado ao microscópio especular.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The objectives were to determine the effects of age and genetic group on characteristics of the scrotum, testes and testicular vascular cones (TVC), and on sperm production and semen quality in 107 Bos indicus, B, taurus and cross-bred bulls at three artificial insemination (AI) centers in Brazil. In addition, predictors of sperm production and semen quality were identified. In general, scrotal circumference (SC), scrotal shape score, scrotal neck perimeter, and testicular size (length, width and volume) increased (P < 0.05) with age. Although there were no significant differences among genetic groups for SC or testicular size, B. indicus bulls had the least pendulous scrotal shape, the shortest scrotal neck length, and the greatest scrotal neck perimeter (P < 0.05). Fat covering the TVC was thinner (P < 0.05) in bulls <= 36 months of age and in B. taunts bulls than in older bulls and B. indicus bulls, respectively. Age and genetic group did not affect testicular ultrasonic echotexture. B. indicus bulls tended (P < 0.1) to have the lowest average scrotal surface temperature (SST). In general, ejaculate volume, total number of spermatozoa and number of viable spermatozoa increased (P < 0.05) with age. However, there was no significant effect of age on sperm concentration, motility, major and total defects. The proportion of spermatozoa with minor defects was highest (P < 0.05) in bulls 37-60 months of age. B. indicus bulls had higher (P < 0.01) sperm concentration, total number of spermatozoa and number of viable spermatozoa than B. taunts bulls, with intermediate values for cross-bred bulls. Increased sperm production was associated with increased testicular volume, SC, TVC fat cover, and SST top-to-bottom gradient. Decreased semen quality was associated with increased SC and bottom SST, and decreased scrotal shape, scrotal neck perimeter and vascular cone diameter. In summary, age and genetic group affected the characteristics of the scrotum, testes, and TVC, sperm production and semen quality. In addition, characteristics of the scrotum, testes and TVC were associated with sperm production and semen quality in bulls and could be assessed for breeding soundness evaluation. (c) 2002 Elsevier B.V. All rights reserved.
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Avaliaram-se os efeitos da progesterona (P4) sobre o crescimento folicular e na endocrinologia reprodutiva em ovelhas Bergamácia. Quatorze ovelhas sincronizadas com prostaglandinas (PGF2alfa ) foram distribuídas em dois grupos (n=7/grupo): grupo-controle e grupo tratado com progesterona (CIDR) depois da ovulação (dia zero). Desde o dia anterior à aplicação de PG até o dia 10, realizaram-se monitoramentos ultra-sonográficos para estabelecer o crescimento folicular. Amostras de sangue foram colhidas para a determinação de P4 desde o dia anterior à aplicação de PG até o dia 10 depois da ovulação. Para o perfil dos pulsos de hormônio luteinizante (LH), as colheitas de sangue ocorreram em intervalos de 30 minutos por um período de oito horas, nos dias um e seis. As taxas de crescimento diferiram (P<0,001) entre os grupos, 0,91±0,15 e 0,70±0,16mm/dia para os grupos controle e tratado, respectivamente. Os dias do platô dos animais controle e tratados foram de 1,9±0,72 e 2,9±0,45 (P<0,05), respectivamente. As concentrações médias de progesterona (P<0,001) foram diferentes entre os tratamentos. A freqüência dos pulsos diferiu no primeiro dia do ciclo (P<0,01), com valores de 2,55±0,09 pulsos/8 horas no grupo-controle e de 1,49±0,11 pulsos/8 horas no grupo tratado. No sexto dia, o grupo-controle 2,20±0,09 pulsos/8 horas apresentou maior número de pulsos (P<0,05) que o grupo tratado, 1,22±0,11 pulsos/8 horas. Os efeitos inibitórios da progesterona exógena no diâmetro do folículo dominante foram mediados pela redução na freqüência dos pulsos de LH.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Objectives: This pilot study aims to investigate the prevalence of noncarious cervical lesions (NCCLs) in a student population at the Faculty of Dentistry of Aracatuba-UNESP and to assess the potential relation between buccal hygiene habits and the presence and number of NCCLs.Methods: This study was conducted with a sample of 58 young volunteers (15 men and 43 women; mean age, 23.6 +/- 1.8 years and 22.3 +/- 2.4 years, respectively). The research was divided into three steps: 1) clinical assessment; 2) oral-hygiene practices self-report questionnaire; and 3) analysis of toothbrush filament deformations. After the clinical exam the participants were divided into two groups, a control group (without NCCLs) and a test group (NCCLs), according to NCCL presence. The data were statistically analyzed with SPSS 16.0 software, using t-test, chi(2), Fisher exact test, and Spearman correlation.Results: NCCLs were present in 53% of the subjects. The presence of NCCLs was marginally statistically associated with age (p=0.15) and proportionally more prevalent in male (80%) subjects (p=0.01). NCCLs were more concentrated in the posterior-superior quadrant (93%) in both the right (90%) and left (55%) sides of the mouth. The direct rank correlation was presented between presence of NCCLs and toothbrush firmness; and between number of NCCLs and age and force applied during toothbrushing.Conclusion: Within the limitations of this pilot study, the use of medium and hard toothbrushes and greater force applied during toothbrushing might contribute to the development and/or aggravation of NCCLs.
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The health of a peri-implant tissue is a critical factor for the long-term success of treatment with extraoral implants. However, infection and inflammation may occur and lead to implant loss and prostheses failure. Therefore, some postsurgical care as hygiene with soap and water, soft toothbrush, and Superfloss type dental floss and medication with anti-inflammatory and antibiotic are suggested to avoid complications. In addition, a thin and smooth layer of subcutaneous tissue in the peri-implant area should be preserved during implant insertion to favor the assistance recommended in this phase.
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This in situ/ex vivo study evaluated whether saliva stimulated by chewing gum could prevent or reduce the wear and the percent change in microhardness (%SMH) of bovine and human enamel submitted to erosion followed by brushing abrasion immediately or after 1 h. During 2 experimental 7-day crossover phases, 9 previously selected volunteers wore intraoral palatal devices, with 12 enamel specimens (6 human and 6 bovine). In the first phase, the volunteers immersed the device for 5 min in 150 ml of cola drink, 4 times per day (at 8, 12, 16 and 20 h). Immediately after the immersions, no treatment was performed in 4 specimens, 4 other specimens were immediately brushed (0 min) using a fluoride dentifrice, and the device was replaced into the mouth. After 60 min, the remaining 4 specimens were brushed. In the second phase, the procedures were repeated, but after the immersions, the volunteers stimulated the salivary flow rate by chewing a sugar-free gum for 30 min. Changes in wear and %SMH were measured. ANOVA and Tukey's test showed statistical differences (p < 0.05) for the following comparisons. The chewing gum promoted less wear and %SMH. A decreasing %SMH and an increasing enamel wear were observed in the following conditions: erosion only, 60 min and 0 min. The human enamel presented greater %SMH and less wear compared to bovine enamel. The data suggest that the salivary stimulation after an erosive or erosive/abrasive attack can reduce the dental wear and the %SMH.
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This in situ/ex vivo study assessed the effect of different concentrations of fluoride in dentifrices on dentin subjected to erosion or to erosion plus abrasion. Ten volunteers took part in this crossover and double-blind study performed in 3 phases (7 days). They wore acrylic palatal appliances containing 4 bovine dentin blocks divided in two rows: erosion and erosion plus abrasion. The blocks were subjected to erosion by immersion ex vivo in a cola drink (60 s, pH 2.6) 4 times daily. During this step, the volunteers brushed their teeth with one of three dentifrices D (5,000 ppm F, NaF, silica); C (1,100 ppm F, NaF, silica) and placebo (22 ppm F, silica). Then, the respective dentifrice slurry (1: 3) was dripped on dentin surfaces. While no further treatment was performed in one row, the other row was brushed using an electric toothbrush for 30 s ex vivo. The appliances were replaced in the mouth and the volunteers rinsed with water. Dentin loss was determined by profilometry and analyzed by 2-way ANOVA/Bonferroni test (alpha = 0.05). Dentin loss after erosive-abrasive wear was significantly greater than after erosion alone. Wear was significantly higher for the placebo than for the D and C dentifrices, which were not significantly different from each other. It can be concluded that the presence of fluoride concentrations around 1,100 ppm in dentifrices is important to reduce dentin wear by erosion and erosion + abrasion, but the protective effect does not increase with fluoride concentration. Copyright (C) 2008 S. Karger AG, Basel.
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The aim of this study was to evaluate the periapical healing after the use of membrane, bone graft, and mineral trioxide aggregate (MTA) in apical surgery of dogs' teeth. Apical lesions were induced in 48 roots of 6 dogs after coronal access and pulpal removal. Apical surgery consisted of osteotomy with trephine bur for the standardization of the critical surgical cavities, followed by apicoectomy, curettage, preparation of the root-end cavities with the aid of the ultrasonic device, and retrofilling with MTA. The surgical sites were divided into: group 1-filled with blood; group 2-filled with blood and recovered with membrane; group 3-filled with bone graft; and group 4-filled with bone graft and recovered with membrane. The results showed that the inflammatory infiltrate, the periapical healing process, and the behavior of MTA was the same in all groups, including the mineralization stimulation. It was concluded that the use of membranes and bone graft materials isolated or associated in apical surgery did not alter the periapical healing process after the root-end filling with MTA. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: 309-314)
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Purpose: To analyze the smear layer and the hybrid layer in noncarious and carious dentin prepared by different cutting instruments and restored with composite resin. Study design: Cavities were randomly prepared in 160 specimens (noncarious and artificial carious dentin) by high-speed diamond tips (KG Sorensen 1013), air abrasion system (Prepstart, Danville Engineering), ultrasonic tip (CVDentus 8.3231-1), and ultrasonic tip associated with ultrasonic cavitation by water for 10 s. Half of the cavities in each group were conditioned with 37% phosphoric acid for 15 s. The amount of smear layer and dentinal tubules present were analyzed using scanning electron microscopy and graded from 0 to 3. Cavities were prepared in another 20 noncarious specimens and 20 carious specimens and restored with adhesive composite resin system. The restorations were hemisected longitudinally and analyzed using scanning electron microscopy to evaluate the hybrid layer and resinous prolongation characteristics, using scores ranging from 1 to 6. Results: The data were statistically analyzed using Kruskal-Wallis and Dunn tests at 5% of significance level. There was evidence that the most efficient smear layer removal was the acid etching in the noncarious dentin and the water ultrasonic cavitation in the carious dentin. The hybrid layer formed on the noncarious and carious dentin prepared by the ultrasonic tip was more regular than in the specimens prepared by high-speed diamond tip, with many resinous prolongations. Conclusion: The ultrasonic tip seems to be a promising tool for carious dentin cavity preparation. Microsc. Res. Tech. 73:597-605, 2010. (C) 2009 Wiley-Liss, Inc.