OBJECTIVES: The purpose of this study was to investigate changes in the composition of artificial cariogenic biofilms using a Streptococcus mutans biofilm model over a period of time. METHODS: We analyzed the dry weight, colony forming unit (CFU) number, extracellular polysaccharide (EPS) biovolume, and acid production rate of S. mutans biofilms formed on saliva-coated hydroxyapatite discs after 26 h, 50 h, 74 h, 98 h, 171 h, and 195 h. In addition, we performed a laser scanning confocal fluorescence microscopy to determine the bacterial volume, EPS biovolume, and biofilm thickness. We calculated the biofilm density using dry weight and EPS biovolume. RESULTS: Over a period of time, there was no change in the CFU number and acid production rate of S. mutans biofilms, but there was an increase in the dry weight and EPS biovolume of S. mutans biofilms. The bacterial volume, EPS biovolume, and biofilm thickness only increased in the 50-h-old biofilm; however, no change was observed in 50-195-h-old biofilms. In addition, an increase in the biofilm density was observed over time. CONCLUSIONS: These results suggest that the acid production ability of cariogenic biofilms does not change, but the biofilm density increases over time. However, due to scientific information, further research needs to be conducted in the field of dentistry to get further insights on the progression of cariogenic biofilms over time.
Biofilms ; Dentistry ; Durapatite ; Microscopy, Fluorescence ; Stem Cells ; Streptococcus mutans

PURPOSE: Controversy exists over the pain during prostate biopsy. Periprostatic nerve block is a commonly used anaesthetic technique during transrectal ultrasound (TRUS)-guided prostate biopsy. The recent trend toward increasing the number of cores has become popular. This practice further increases the need for a proper anaesthetic application. We compared the efficacy of periprostatic nerve block with or without intraprostatic nerve block. MATERIALS AND METHODS: We conducted a prospective double-blinded placebo-controlled study at our institute with 142 consecutive patients. Patients were randomly assigned into 3 groups. Group 1 received periprostatic nerve block with intraprostatic nerve block with 1% lignocaine. Group 2 patients were administered periprostatic nerve block only with 1% lignocaine. Group 3 received no anaesthesia. Patients were asked to grade their level of pain by using an 11-point linear analogue scale at the time of ultrasound probe insertion, at the time of anaesthesia, during biopsy, and 30 minutes after biopsy. RESULTS: The study groups were comparable in demographic profile, prostate-specific antigen (PSA) level, and prostate size. The mean pain scores at the time of biopsy in groups 1, 2, and 3 were 2.70, 3.39, and 4.16, respectively. Group 1 recorded the minimum mean pain score of 2.70 during prostate biopsy, which was significantly lower than the scores of groups 2 and 3 (p<0.001). There were no significant differences in pain scores among the 3 groups during probe insertion, during anaesthesia, or at 30 minutes after biopsy (p>0.05). CONCLUSIONS: Periprostatic nerve block with intraprostatic nerve block provides better pain control than does periprostatic nerve block alone in TRUS-guided prostate biopsy.
Analgesia ; Biopsy ; Biopsy, Needle ; Humans ; Lidocaine ; Needles ; Nerve Block ; Prospective Studies ; Prostate ; Prostate-Specific Antigen

Trans-trans farnesol (tt-farnesol) is a bioactive sesquiterpene alcohol commonly found in propolis (a beehive product) and citrus fruits, which disrupts the ability of Streptococcus mutans (S. mutans) to form virulent biofilms. In this study, we investigated whether tt-farnesol affects cell-membrane function, acid production and/or acid tolerance by planktonic cells and biofilms of S. mutans UA159. Furthermore, the influence of the agent on S. mutans gene expression and ability to form biofilms in the presence of other oral bacteria (Streptococcus oralis (S. oralis) 35037 and Actinomyces naeslundii (A. naeslundii) 12104) was also examined. In general, tt-farnesol (1 mmol x L(-1)) significantly increased the membrane proton permeability and reduced glycolytic activity of S. mutans in the planktonic state and in biofilms (P < 0.05). Moreover, topical applications of 1 mmol x L(-1) tt-farnesol twice daily (1 min exposure/treatment) reduced biomass accumulation and prevented ecological shifts towards S. mutans dominance within mixed-species biofilms after introduction of 1% sucrose. S. oralis (a non-cariogenic organism) became the major species after treatments with tt-farnesol, whereas vehicle-treated biofilms contained mostly S. mutans (>90% of total bacterial population). However, the agent did not affect significantly the expression of S. mutans genes involved in acidogenicity, acid tolerance or polysaccharide synthesis in the treated biofilms. Our data indicate that tt-farnesol may affect the competitiveness of S. mutans in a mixed-species environment by primarily disrupting the membrane function and physiology of this bacterium. This naturally occurring terpenoid could be a potentially useful adjunctive agent to the current anti-biofilm/anti-caries chemotherapeutic strategies.
Actinomyces ; physiology ; Biofilms ; drug effects ; Cell Membrane Permeability ; drug effects ; Colony Count, Microbial ; Durapatite ; Farnesol ; pharmacology ; Gene Expression Regulation, Bacterial ; drug effects ; Glycolysis ; Humans ; Hydrogen-Ion Concentration ; Microbial Viability ; drug effects ; Plankton ; drug effects ; Saliva ; microbiology ; Streptococcus mutans ; drug effects ; genetics ; physiology ; Streptococcus oralis ; physiology