Caries progression and inhibition in human and bovine root dentine in situ

Since the use of bovine instead of human dentine to evaluate cariogenic and anticariogenic substances is not well established, this in situ study was conducted. Eleven volunteers wore palatal acrylic devices containing 4 dentine slabs (2 human and 2 bovine). Sucrose solution (20%) was dripped over all slabs 4 times a day, simulating a cariogenic challenge. Dentifrice slurries, fluoridated or not, were dripped over specified dentine slabs 3 times a day to evaluate caries reduction. After 14 days, the biofilm formed on the dentine slabs was collected for microbiological analysis. In dentine, mineral loss (DeltaZ) and lesion depth (LD) were determined by cross-sectional microhardness and by polarized light microscopy, respectively. The total streptococci and mutans streptococci counts in the biofilm formed either on human or on bovine slabs, whether treated or not with fluoride dentifrice, were not statistically different. The DeltaZ and the LID values of dentine treated with fluoride dentifrice were significantly lower than the values of dentine treated with non-fluoride dentifrice. The differences in the DeltaZ and LD values between the human and bovine dentine were not statistically significant. The results suggest that bovine dentine can be used instead of human to evaluate caries development and inhibition. Copyright (C) 2003 S. Karger AG, Basel.

Evaluation of tensile tetention of Y-TZP crowns after long-term aging: Effect of the core substrate and crown surface conditioning

This study evaluated the effect of the core substrate type (dentin and composite resin) on the retention of crowns made of yttrium oxide stabilized tetragonal zirconia polycrystal (Y-TZP), submitted to three inner surface conditionings. For this purpose, 72 freshly extracted molars were embedded in acrylic resin, perpendicular to the long axis, and prepared for full crowns: 36 specimens had crown preparations in dentin; the remaining 36 teeth had the crowns removed, and crown preparations were reconstructed with composite resin plus fiber posts with dimensions identical to the prepared dentin. The preparations were impressed using addition silicone, and 72 Y-TZP copings for the tensile test were produced. Cementation was performed with a dual-cured cement containing phosphate monomers. For cementation, the crown preparation (dentin or resin) was conditioned with the adhesive system, and the ceramic was subjected to one of three surface treatments: isopropyl alcohol, tribochemical silica coating, or thin low-fusing glassy porcelain layer application plus silanization. After 24 hours, all specimens were submitted to thermocycling (6000 cycles) and placed in a special tensile testing device in a universal testing machine to determine failure loads. The failure modes of all samples were analyzed under a stereomicroscope. Two-way analysis of variance showed that the surface treatment and substrate type (alpha=0.05) affected the tensile retention results. The dentin substrate presented the highest tensile retention values, regardless of the surface treatment. When the substrate was resin, the tribochemical silica coating and low-fusing glaze application plus silanization groups showed the higher retention values.

Microtensile Bond Strenh Between Indirect Composite Resin Inlays and Dentin: Effect of Cementation Strategy and Mechanical Aging

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise dos processos de infiltração, percolação, retenção e evaporação em solos arenoso e residuais utilizando lisímetro

The mobility of water in the soil is a difficult process to be quantified. During precipitation, there is a portion of the water that infiltrates, which is very important for recovering the groundwater balance. This work studies the mobility of water in sandy soils with different textures and residual soils through experiments mounted in lysimeters. The lysimeters were mounted on acrylic cylinder with 11.3 cm diameter and 25.0 cm in length. The sand was deposited using the process sand rain. In the tests it was maintained a hydraulic head of two centimeters above the surface with the aid of a Mariotte flask. The portions of water were controlled in the experiments using relations between weight and volume measurements over time. The data were obtained by monitoring the input and output volumes of water through calibrated reservoir and system weight by an electronic balance. The infiltration front was monitored with the aid of a digital camera. The results indicate that the smaller the particle size of the sand, the lower the speed of the saturation front, the higher the retained volume, the smaller the basic rate of infiltration and the lowest speed of percolation. Moreover, the rate of water loss in the evaporation process indicated no significant difference with variation of the particle size of the samples

Ocorrência de opacidade de cápsula posterior em cães pós-facoemulsificação, com ou sem a utilização de lente intraocular dobrável e efeitos do Nd: Yag Laser

Pós-graduação em Cirurgia Veterinária - FCAV

Análise das microdeformações geradas ao redor de implantes de hexágono externo sob a aplicação de cargas verticais em pilares microunit retos e angulados

Pós-graduação em Odontologia Restauradora - ICT

Avaliação da adesão de Staphylococcus spp. em resina acrílica específica para prótese ocular e alteração de cor de botões de íris artificiais, variando a cor e as técnicas de obtenção, ambos após desinfecção química

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

Resistência à tração de coroas de NiCr cimentadas sobre munhões de liga de titânio, com 4 diferentes tipos de cimentos

In this work of tensile strength was evaluated the efficacy of 4 cements (S. S. White zinc phoshate, Ketac Cem Easymix glass ionomer, RelyX Luting 2 composite resin/glass ionomer and Panavia 21 TC special acrylic resin) used to fix NiCr crowns to usinated titanium alloy abutments. Were used 40 abutments distributed in groups of 10 elements, to each material. The mechanical essays were developed at a MTS 810 universal machine, adjusted to a 0.5 mm/m velocity. The ANOVA applied to data pointed out the existence of significant differences between groups; the subsequent Tukey´s test (p<0.05) also detected significant differences, except at comparisons of phosphate versus RelyX and phosphate versus Ketac Cem. The better performance was presented by Panavia 21 (1,127.996 N); RelyX (478.197 N) showed itself similar only to phosphate (430.662 N), wich had a performance similar to that of Ketac Cem (227.705 N).

Insecticidal Effect of Extracts from Native Plants of Mato Grosso do Sul State on Sitophilus zeamais Mots (Coleoptera: Curculionidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação histopatológica da cápsula posterior associada ao implante intraocular com superfície modificada: estudo experimental em coelhos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Dispositivo microfluídico de borracha natural (LAB-ON-A-CHIP)

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

Efeito do tipo de adesivo e do seu mecanismo de ativação, assim como da viscosidade da resina composta, na resistência de união à dentina antes e após envelhecimento artificial

Pós-graduação em Odontologia Restauradora - ICT

Preparação e caracterização de nanocompósitos de Fe@SiO2, Fe@Fe3O4 e Fe3O4@PNIPAM

Pós-graduação em Química - IQ

Caracterização química e resistência à flexão de uma resina acrílica após a incorporação de um polímero com atividade antimicrobiana

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Resistência à flexão de uma resina acrílica após a incorporação de um polímero antimicrobiano

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)