2 resultados para Ageing process

em BORIS: Bern Open Repository and Information System - Berna - Suiça


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The aim of our study is to evaluate the performance of surface sealants and conventional polishing after ageing procedures. Eighty circular composite restorations were performed on extracted human molars. After standardised roughening, the restorations were either sealed with one of three surface sealants (Lasting Touch (LT), BisCover LV (BC), G-Coat Plus (GP) or a dentin adhesive Heliobond (HB)) or were manually polished with silicon polishers (MP) (n = 16). The average roughness (Ra) and colourimetric parameters (CP) (L*a*b*) were evaluated. The specimens underwent an artificial ageing process by thermocycling, staining (coffee) and abrasive (toothbrushing) procedures. After each ageing step, Ra and CP measurements were repeated. A qualitative surface analysis was performed with SEM. The differences between the test groups regarding Ra and CP values were analysed with nonparametric ANOVA analysis (α = 0.05). The lowest Ra values were achieved with HB. BC and GP resulted in Ra values below 0.2 μm (clinically relevant threshold), whereas LT and MP sometimes led to higher Ra values. LT showed a significantly higher discolouration after the first coffee staining, but this was normalised to the other groups after toothbrushing. The differences between the measurements and test groups for Ra and CP were statistically significant. However, the final colour difference showed no statistical difference among the five groups. SEM evaluation showed clear alterations after ageing in all coating groups. Surface sealants and dentin adhesives have the potential to reduce surface roughness but tend to debond over time. Surface sealants can only be recommended for polishing provisional restorations.

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Periodontitis is a multi-factorial disease and in most cases also a disease with a chronic progression. Exposure to factors which contribute to periodontitis occurs over a long period, so that at the time of diagnosis it may be difficult to identify and evaluate what co-factors have contributed to its development. These include exposure to bacteria and viruses, inflammation, genetic factors, health behaviours and a variety of social factors, socio-economic status, behavioural and nutritional habits, the ability to cope with stress and the ability of the immune system to fight infections. Many patients in their 50s also experience other conditions such as heart disease, diabetes mellitus, or rheumatoid arthritis and recent reports on the associations and potential biological mechanisms by which periodontitis can be linked to other systemic diseases suggest that the patient with periodontitis is a challenged individual. Neither individuals nor their oral health care providers are currently prepared for the challenges in oral health care as the expectation of successful ageing with remaining and aesthetically functional teeth is increasing. The scientific evidence is, however, growing, and while the opportunities to prepare for successful ageing exist they must be included in the educational process of both current and future oral health care providers and their patients.