Caracterização Microestrutural e Tribocorrosiva de Sistemas Metalocerâmicos Odontológicos do Tipo Ni-Cr/Porcelana E Ni-Cr/Ti/Porcelana

The partial fixed prosthodontics restoration is used to rehabilitate form and function of partial or total compromised teeth, having to remain permanently joined to remainder tooth. The most useful material on prosthodontics is the feldspar porcelain, commercialized as aluminosilicate powders. Dental porcelains are presented with limited mechanical properties to rehabilitate extensive spaces. The association with Ni-Cr metallic systems (metal-ceramic system) allows that the metallic substructure compensates the fragile porcelain nature, preserving the thermal insulation and aesthetics desirable, as well as reducing the possibility of cracking during matication efforts. Cohesive flaws by low mechanical strength connect the metallic substructure to the oral environment, characterized by a electrolytic solution (saliva), by aggressive temperature, pH cyclic changes and mechanical requests. This process results on ionic liberation that could promote allergic or inflammatory responses, and/or clinical degradation of ceramometal system. The aim of this study was to evaluate the presence of an intermediate titanium layer on the microscopic fracture behavior of porcelains on ceramometal systems. Plasma deposition of titanium films result in regular passivating oxide layers which act as barriers to protect the metallic substrate against the hazardous effects of corrosive saliva. Tribocorrosion tests were performed to simulate the oral environment and mechanical stress, making it possible the early detection of crack formation and growth on metal-ceramic systems, which estimate the adherence between the compounds of this system. Plain samples consisting of dental feldspar porcelain deposited either onto metallic substrates or titanium films were fired and characterized by scanning electron microscopy. The result showed that the titanium film improved the adherence of the system compared to conventional metal-ceramic interfaces, thus holding crack propagation

Tradução, adaptação cultural e propriedades psicométricas da versão brasileira do Short-Form of the Mobility Assessment Tool (MAT-sf)

Objectives: to translate and assess the psychometric properties of the Brazilian short-form of the Mobility Assessment Tool (MAT-sf) in Brazilians community elderly. Methds: the 12 items MAT-sf went through the process of translation and back translation into Portuguese of the Brazil, considering the semantic and cultural adaptation. In a sample of 150 aged 65-74 years living in the community, the instrument's psychometric properties were evaluated by analysis of convergent and construct validity and test-retest reliability. The main outcomes measures used for validation included in the battery of tests of physical ability, self-repor measures of functional limitations, health, depression, cognitive and sex. The test-retest reliability of the instrument was assessed using the intra-class correlation coefficient (ICC), 40 subjects were reassessed after an interval of 14 days of assessment. Results: the concurrent validity for the MAT-sf was evidenced by significant correlations with SPPB (r = 0,53), number of functional limitations (r = -0,62) and depressive symptoms (r = -0,45). The construct validity of the instrument was measured by gradual and significant increase of the MAT-sf scores with high levels of physical performance and with positive self-reported health, also found that MAT-sf scores were statistically differents according to sex. The variation in MAT-sf scores (R2 = 0,41) was explained by SPPB, number of limitations for activities of daily life and depressive symptoms. High values for test-retest reliability was evidencend by ICC = 0,94, 95% CI = 0,90 0,97. Conclusions: the Brazilian version of the short-form of the Mobility Assessment Tool has values of validity and reliability to ensure its use in elderly populations living in communities