Osteogenesis-inducing calcium phosphate nanoparticle precursors applied to titanium surfaces

This study investigated the effects of the morphology and physicochemical properties of calcium phosphate (CaP) nanoparticles on osteogenesis. Two types of CaP nanoparticles were compared, namely amorphous calcium phosphate (ACP) nano-spheres (diameter: 9-13 nm) and poorly crystalline apatite (PCA) nano-needles (30-50 nm x 2-4 nm) that closely resemble bone apatite. CaP particles were spin-coated onto titanium discs and implants; they were evaluated in cultured mouse calvarial osteoblasts, as well as after implantation in rabbit femurs. A significant dependence of CaP coatings was observed in osteoblast-related gene expression (Runx2, Col1a1 and Spp1). Specifically, the PCA group presented an up-regulation of the osteospecific genes, while the ACP group suppressed the Runx2 and Col1a1 expression when compared to blank titanium substrates. Both the ACP and PCA groups presented a more than three-fold increase of calcium deposition, as suggested by Alizarin red staining. The removal torque results implied a slight tendency in favour of the PCA group. Different forms of CaP nanostructures presented different biologic differences; the obtained information can be used to optimize surface coatings on biomaterials. © 2013 IOP Publishing Ltd.

Prevalence of deciduous tooth erosion in childhood

Objectives: The objective of this study was to estimate the prevalence of deciduous tooth erosion and to identify possible associations with sex, age and toothbrushing frequency in children aged 4-6 years. Methods: The sample was drawn from attendants (n = 7058) of 57 public preschools in a Brazilian city. Tooth wear index was used to evaluate erosion. Descriptive statistical analysis consisted of the calculation of the prevalence of dental erosion; chi-squared and Fisher's exact tests were performed to verify the association between dental erosion and sex, age and toothbrushing frequency. Results: Two thousand and seven hundred and fifty-nine preschool students were examined. Deciduous tooth erosion was observed in 0.6% of children and its incidence did not differ between sexes. The highest prevalence was observed in children aged 6 years (58.3%) and the most affected sextants were the fourth (22.86%) and sixth (20.00%), indicating that lingual and occlusal tooth surfaces were most frequently involved. The degree of involvement was classified as incipient in 54.29% of children and moderate in 45.71%. The significance level was set at 5%. No association was found between erosion and sex, age or toothbrushing frequency. Conclusions: The prevalence of deciduous tooth erosion was low in Brazilian children, and this disorder is not considered a public health problem in this part of the population. © 2013 John Wiley & Sons A/S.

Commercially pure titanium implants with surfaces modified by laser beam with and without chemical deposition of apatite. Biomechanical and topographical analysis in rabbits

Objectives: The purpose of this study was to evaluate the surfaces of commercially pure titanium (cp Ti) implants modified by laser beam (LS), without and with hydroxyapatite deposition by the biomimetic method (HAB), without (HAB) and with thermal treatment (HABT), and compare them with implants with surfaces modified by acid treatment (AS) and with machined surfaces (MS), employing topographical and biomechanics analysis. Methods: Forty-five rabbits received 75 implants. After 30, 60, and 90 days, the implants were removed by reverse torque and the surfaces were topographically analyzed. Results: At 30 days, statistically significant difference (P < 0.05) was observed among all the surfaces and the MS, between HAB/HABT and AS and between HAB and LS. At 60 days, the reverse torque of LS, HAB, HABT, and AS differed significantly from MS. At 90 days, difference was observed between HAB and MS. The microtopographic analysis revealed statistical difference between the roughness of LS, HAB, and HABT when compared with AS and MS. Conclusions: It was concluded that the implants LS, HAB, and HABT presented physicochemical and topographical properties superior to those of AS and MS and favored the osseointegration process in the shorter periods. In addition, HAB showed the best results when compared with other surfaces. © 2012 John Wiley & Sons A/S.

Histologic and biomechanical evaluation of 2 resorbable-blasting media implant surfaces at early implantation times

This study evaluated 3 implant surfaces in a dog model: (1) resorbable-blasting media + acid-etched (RBMa), alumina-blasting + acid-etching (AB/AE), and AB/AE + RBMa (hybrid). All of the surfaces were minimally rough, and Ca and P were present for the RBMa and hybrid surfaces. Following 2 weeks in vivo, no significant differences were observed for torque, bone-to-implant contact, and bone-area fraction occupied measurements. Newly formed woven bone was observed in proximity with all surfaces.

Estimates of hourly diffuse radiation on tilted surfaces in southeast of brazil

The global radiation incident on a tilted surfaces consists of components direct, diffuse and reflected from the ground. On a hourly database, the direct radiation can be calculated by geometric projections (ratio of the incidence angle to the solar zenith angle). The reflected radiation has a small effect on calculations and may be calculated with an isotropic model. Both components presents dependence of measures in incidence or horizontal surface. The great difficulty is to evaluate the diffuse radiation by variations of circumsolar, brightness horizontal, isotropic and anisotropic subcomponents. This study evaluated twenty models to estimate hourly diffuse radiation incident on tilted surfaces at 12.85° (latitude - 10°), 22.85° (latitude) and 32.85° (latitude + 10°) facing to North, under different cloudiness sky conditions, in Botucatu, São Paulo State, Brazil (22°53' S, 48°26' W and 786 m above the mean sea level). In contrast, models for estimating the diffuse component show major differences, which justify the validation for local calibrations. There is a decrease of the maximum total radiation scattered with increasing atmospheric transmissivity and inclination angle. The best results are obtained by anisotropic models: Ma and Iqbal, Hay, Reindl et al. and Willmott; isotropic: Badescu and Koronakis, and the Circumsolar model. The increase of the inclination angle allows for a reduction in the performance of statistical parametric models for estimating the hourly diffuse radiation.

Tribocorrosion behaviour of anodic treated titanium surfaces intended for dental implants

Tribocorrosion plays an important role in the lifetime of metallic implants. Once implanted, biomaterials are subjected to micro-movements in aggressive biological fluids. Titanium is widely used as an implant material because it spontaneously forms a compact and protective nanometric thick oxide layer, mainly TiO2, in ambient air. That layer provides good corrosion resistance, and very low toxicity, but its low wear resistance is a concern. In this work, an anodizing treatment was performed on commercial pure titanium to form a homogeneous thick oxide surface layer in order to provide bioactivity and improve the biological, chemical and mechanical properties. Anodizing was performed in an electrolyte containing β-glycerophosphate and calcium acetate. The influence of the calcium acetate content on the tribocorrosion behaviour of the anodized material was studied. The concentration of calcium acetate in the electrolyte was found to largely affect the crystallographic structure of the resulting oxide layer. Better tribocorrosion behaviour was noticed on increasing the calcium acetate concentration. © 2013 IOP Publishing Ltd.

Desempenho de métodos baseados na indução de fluorescência para a detecção de lesões de cárie em superfícies oclusais e proximais: estudos in vitro

Pós-graduação em Ciências Odontológicas - FOAR

Eficiência de três cimentos de ionômero de vidro como dissipadores de cargas em bases de restaurações de resina composta: análise por meio da extensometria elétrica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparação entre a inspeção visual, radiografia interproximal e a fluorescência a laser em relação ao diagnóstico de lesões cariosas oclusais e a determinação do plano de tratamento

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

Influência do substrato, dentes decíduos e permanentes, e da aplicação de clorexidina na resistência de união de sistemas adesivos à dentina

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

Desempenho de sistema de diagnóstico óptico para detecção de lesões de cárie

Pós-graduação em Ciências Odontológicas - FOAR

Resistência adesiva de um sistema auto-condicionante e um convencional simplificado, aplicados à dentina tratada com diferentes condicionadores

Pós-graduação em Odontologia - FOAR

Desenvolvimento de um paralelizador intra-oral e verificação de sua precisão como método de transferência de planos de guia: Estudo laboratorial

Pós-graduação em Odontologia Restauradora - ICT

Avaliação da influência da inclinação das cúspides e da direção das cargas oclusais na distribuição das tensões em próteses implanto-suportadas: estudo através do método dos elementos finitos tridimensionais

Pós-graduação em Odontologia - FOA

Infiltração marginal em restaurações de resina composta após tratamento dentinário com abrasão a ar e sistemas adesivos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)