Utilização de probióticos para o controle da prevalência de Candida oral em pacientes edentados totais / The use of probiotics for control of the prevalence of oral Candida in total edentulous patients

Probióticos são microrganismos vivos que conferem benefícios à saúde dos indivíduos, quando administrados em quantidades adequadas. Além de promoverem uma melhora no sistema gastrointestinal, os probióticos são conhecidos por sua capacidade de inibirem o crescimento de microrganismos patogênicos. O presente trabalho objetivou avaliar a influência dos probióticos na redução da prevalência de Candida oral de indivíduos usuários de próteses totais. Para realização deste estudo foi elaborado o bioproduto contendo probióticos, Lactobacillus rhamnosus e Lactobacillus acidophilus. O protocolo do estudo foi duplo-cego randomizado, sendo que os sujeitos da pesquisa foram divididos aleatoriamente em dois grupos: experimental (probióticos) e controle (placebo). Os participantes utilizaram o produto durante cinco semanas e o resultado foi avaliado segundo a contagem de leveduras isoladas em unidades formadoras de colônias (UFC/mL), antes e após a intervenção. Paralelamente, a esta fase clínica da pesquisa, foram testadas in vitro a ação de outras cepas de Lactobacillus com a finalidade de verificar a associação entre a cepa de Lactobacillus com a redução das espécies de Candida isoladas do palato e das próteses, bem como, com a sensibilidade aos antifúngicos, miconazol e nistatina. Também foi pesquisado um dos principais mecanismos de ação contra patógenos, por Lactobacillus spp, a produção de bacteriocinas. Os resultados inferem que as cepas de probióticos testadas: foram eficazes na redução da prevalência de Candida oral de usuários de próteses totais; in vitro, inibiram o crescimento de Candida sp, sendo L. rhamnosus Lr-32 a cepa com melhor resultado e não produzem bacteriocinas quando em contato com a levedura.

Probiotics are live microorganisms that confer benefits to the health of an individual when administered in adequate amounts. In addition to promoting an improvement in a gastrointestinal system, the probiotics are known for their ability to inhibit the growth of pathogenic microorganisms. The present study sought to evaluate the capacity of probiotics strains in reducing the prevalence of oral Candida in denture wearers. For this study, the by-product was elaborated containing probiotics, such as Lactobacillus rhamnosus and Lactobacillus acidophilus. The study protocol was randomized, double-blind, being that the subjects of the research were randomly sorted into two groups: experimental (probiotics) and control (placebo). The participants utilized the product daily for five weeks and the result was evaluated according to the amount of yeasts isolated in colony-forming units (CFU), before and after the intervention. In parallel to this clinical phase, the action of other Lactobacillus strains were tested in vitro, with the purpose of verifying the relation between the strain of Lactobacillus and the reduction of Candida species isolated from the palate and the prostheses, as well as, with the sensitivity to antifungal agents, miconazole and nystatin. The production of bacteriocins is one of the main mechanisms of action by Lactobacillus spp. against pathogens, and was analised. The results imply that the strains of tested probiotics: in vivo, were effective in reducing the prevalence of oral Candida for denture wearers; in vitro, inhibited the growth of Candida sp, being that L. rhamnosus Lr-32 was the best resulting strain, and the strains did not produce bacteriocins when in contact with yeast.

Study of the surface hardness and modulus of elasticity of conventional and microwave-cured acrylic resins

The aim of this study was to evaluate the following acrylic resins: Clássico®, QC-20® and Lucitone®, recommended specifically for thermal polymerization, and Acron MC® and VIPI-WAVE®, made for polymerization by microwave energy. The resins were evaluated regarding their surface nanohardness and modulus of elasticity, while varying the polymerization time recommended by the manufacturer. They were also compared as to the presence of water absorbed by the samples. The technique used was nanoindentation, using the Nano Indenter XP®, MTS. According to an intra-group analysis, when using the polymerization time recommended by the manufacturer, a variation of 0.14 to 0.23 GPa for nanohardness and 2.61 to 3.73 GPa for modulus of elasticity was observed for the thermally polymerized resins. The variation for the resins made for polymerization by microwave energy was 0.15 to 0.22 GPa for nanohardness and 2.94 to 3.73 GPa for modulus of elasticity. The conclusion was that the Classico® resin presented higher nanohardness and higher modulus of elasticity values when compared to those of the same group, while Acron MC® presented the highest values for the same characteristics when compared to those of the same group. The water absorption evaluation showed that all the thermal polymerization resins, except for Lucitone®, presented significant nanohardness differences when submitted to dehydration or rehydration, while only Acron MC® presented no significant differences when submitted to a double polymerization time. Regarding the modulus of elasticity, it was observed that all the tested materials and products, except for Lucitone®, showed a significant increase in modulus of elasticity when submitted to a lack of hydration.