The purpose of this study was to evaluate the influence of the substratum position and the saliva acquired pellicle (AP) on Candida albicans biofilm development. Poly(methylmethacrylate) (PMMA) disks were fabricated and randomly allocated to experimental groups: HNP (disks placed in a horizontal position and uncoated by pellicle), VNP (disks placed in a vertical position and uncoated by pellicle), HCP (disks placed in a horizontal position and coated by pellicle), and VCP (disks placed in a vertical position and coated by pellicle). Disks were placed in a 24-well plate and a suspension of 107 cells/mL of Candida albicans was added to each well for biofilm development. The plates were aerobically incubated at 35°C. The biofilms were evaluated at 1.5 (adhesion time point), 24, 48, 72, and 96 hours. The number of viable cells was quantified in terms of the colony-forming units per milliliter (CFU/mL). Metabolic activity was measured by the XTT assay. The biofilm structure was analyzed by scanning electron microscopy. The data were analyzed by three-way ANOVA followed by Tukey's test, with significance set at 5%. The vertical groups showed less biofilm formation and lower metabolic activity than the horizontal groups (p< 0.05). Significant differences in cell viability and metabolic activity were observed between the adhesion and other time points (p< 0.05), but these variables were not affected by the presence of the pellicle (p > 0.05). It can be concluded that the substratum position influenced biofilm development.
This clinical study investigated if daily immersion in denture cleansers reduces microbial counts on removable partial denture's (RPD) biofilm. Twenty-five RPD wearer volunteers were selected and instructed to complement the hygiene of their dentures by immersing them in an enzymatic peroxide-based denture cleanser (Polident® 3 minute) once a day for 3 min for a period of 15 days. The biofilm was collected from RPD surfaces with a swab immediately before (baseline) and after the experimental period. The samples were placed in sterile saline solution, sonicated at 7 W and then plated on specific culture media to quantify total microorganisms, total streptococci and Candida spp. counts. Data from both collections were compared by paired t-test (α=0.05). It was observed a significant reduction on total microorganisms' counts in RPD biofilm after denture cleanser use (p=0.007). This reduction was also observed for total streptococci (p=0.0428), but no difference was observed on Candida spp. counts. It was concluded that daily use of denture cleanser improved denture hygiene by reducing total microorganisms and total streptococci from RPD surface but had no effect on Candida spp. population.
Este estudo clínico investigou se a imersão diária de próteses parciais removíveis (PPR) em limpador químico reduz as contagens de micro-organismos no biofilme. Vinte e cinco voluntários que utilizavam PPR foram selecionados e instruídos a complementar a higiene das PPRs imergindo suas próteses em um limpador químico enzimático (Polident® 3 minute) uma vez por dia, por 3 min, durante 15 dias. O biofilme foi coletado da superfície das próteses com auxílio de um swab imediatamente antes (baseline) e após o período experimental. A amostra foi imersa em solução salina estéril, submetida a sonicação a 7 W, e semeada em meios de cultura específicos para quantificar micro-organismos totais, estreptococos totais e Candida spp. Os dados de ambas as coletas foram comparados pelo teste t pareado (α=0,05). Foi observada uma redução significativa nas contagens de micro-organismos totais no biofilme da PPR após o uso do limpador químico (p=0,007). Essa redução também foi observada para estreptococos totais (p=0,0428), mas não foi observada diferença nas contagens de Candida spp. Concluiu-se que o uso diário do limpador químico melhorou a higienização das próteses por reduzir o número de micro-organismos totais e estreptococos totais na superfície da PPR, mas não teve efeito sobre a população de Candida spp.