Acrylic resin has been used in the manufacture of prostheses, however, in the oral cavity, this material starts to retain microorganisms capable of causing gingival inflammation due its porosities. The aim of this study was to evaluate the influence of the use of silicon dioxide as a coating layer applied onto acrylic resin, on the adhesion of Candida albicans (Ca). After the incubation period in Sabouraud Dextrose Broth, a total of 1 ml of the Ca suspension was added to plate wells, each well containing a specimen of acrylic resin. The adhesion ability of Ca on acrylic resin was determined by counting colonies. Three groups (n = 6) of acrylic resin were assessed: with polishing (RP); without polishing (RW); with polishing and coating layer of silicon dioxide (RPC). Ca deposited on the surface of the acrylic resin was also observed using Scanning Electron Microscopy (SEM). Statistical assessment by Kruskal-Wallis and Student-Newman-Keuls Method were done (α = 2%). There was significant difference among the groups. The RPC group showed the lowest growth, with an average of 5.59 Log CFU/cm²; there was a statistically significant difference in relation to group RW, which presented a growth of 6.07 Log CFU/cm² and to group RP with 5.91 Log CFU/cm 2 (p < 000.1). SEM images demonstrated that in the RP and RPC group, the surface of the resin had greater regularity, and smaller number of microorganisms. The application of silicon dioxide coating on acrylic resin appears to be a promising alternative, and its use can help in reducing the adhesion of Ca in prostheses.

Biofilm on acrylic resin dental prostheses may cause gingival inflammation. This study evaluated the influence of a silicon dioxide coating layer applied onto acrylic resin on the adhesion of microorganisms. Blocks (5 x 5 x 3 mm) of acrylic resin were evaluated for surface roughness and divided into two groups: control (CG) and coated with silicon dioxide (LG group). The specimens were evaluated by scanning electron microscopy (n = 1) and by contact angle analysis (n = 3). For the in situ study, 20 volunteers wore acrylic palatal devices containing three samples from each group (n = 60) for 2 days. The biofilm formed was quantified by metabolic activity and total biomass using the crystal violet assay. The results were subjected to Bartlett's normality test and Gamma model with random effect for the response variable (α = 5%). The mean contact angle of the coated group was significantly lower than that of the uncoated group (p < 0.05). The metabolic activity of microorganisms in the biofilm on the blocks treated with coating was significantly lower than that of control blocks (p = 0.02). Regarding the amount of extracellular matrix produced by the microorganisms, there was no difference between the CG and LG group (p = 0.05). The application of a silicon dioxide coating on acrylic resin reduced the activity of the polymicrobial biofilm formed in situ. This coating may be advantageous for patients with conventional complete dentures or implants made of acrylic resin and who have motor difficulties that prevent them from cleaning their prostheses properly.

Objetivo: o objetivo do presente estudo foi determinar a precisão da posição de entrada, apical e angular da instalação de implantes utilizando um sistema guiado através de navegação dinâmica, e compará-lo à técnica sem utilização de guias, realizando cirurgias em ambientes clinicamente simulados. O estudo contemplou as medidas de precisão geral da instalação de implantes, realizada por estudantes de Odontologia utilizando planejamento virtual em modelos dentados. Métodos: dois estudantes de Odontologia sem experiência prévia em Implantodontia instalaram 44 implantes em modelos de mandíbula e maxila. O planejamento de todos os implantes foi realizado virtualmente. As imagens de tomografia computadorizada de feixe cônico (TCFC) foram importadas para um software e sobrepostas para realizar o planejamento virtual. Os primeiros 22 implantes foram instalados utilizando a técnica sem assistência. Os 22 implantes restantes foram instalados utilizando-se um sistema de navegação dinâmica. Novas tomadas tomográficas foram realizadas após a instalação dos implantes. Os dados das TCFCs de planejamento pré-operatório e pós-cirúrgicas foram enviados para análise comparativa. As técnicas guiada e livre foram comparadas entre si e também com a literatura sobre implantes instalados em modelos usando sistemas de guias estáticos e dinâmicos. Resultados: os implantes instalados utilizando o sistema de navegação dinâmica foram significativamente mais precisos, quando comparado à técnica livre. Conclusão: a cirurgia guiada por navegação dinâmica é precisa, promissora e de fácil aprendizado para cirurgiões-dentistas em início de carreira.