Biofilm Mass (biofilm + mass)

Distribution by Scientific Domains


Selected Abstracts


Effect of chlorhexidine mouth rinse on Streptococci counts of tooth-tissue-borne palatal expander biofilm

ORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 3 2008
IT Maruo
Structured Abstract Authors,,, Maruo IT, Rosa EAR, Maruo H, Tanaka O, Guariza Filho O, Ignácio SA, Camargo ES Objectives,,, To assess total Streptococci (TS) counts and biofilm mass over tooth-tissue-borne palatal expander (TTBPE), as well as the effect of chlorhexidine (CHX) mouth rinse on these variables. Design,,, A cross-sectional study design employed clinical procedures and laboratorial techniques. Setting and Sample Population,,, Patients who had TTBPE removal indicated were divided into two groups: a CHX group (n = 26) in which three times a day of 0.2% CHX digluconate mouth rinses were prescribed 7 days before TTBPE removal; and a control (CON) group (n = 25) in which no antimicrobial treatment was applied. Experimental Variable,,, ,Gender', ,Age', and ,TTBPE wear time' were recorded. After TTBPE removal, biofilm mass was determined by the difference between (TTBPE + biofilm) and (TTBPE only) masses. TS counts were determined by biofilm suspension followed by progressive dilutions and culture on Mitis Salivarius agar with incubation at 37°C for 72 h. Outcome Measure,,, Biofilm mass (mg) and Colony Forming Units of TS,/,mg of biofilm (CFU-TS,/,mg) were calculated. Results,,, Total Streptococci mean values in CHX (6.77 × 106CFU-TS,/,mg) were statistically lower (p < 0.01) than those in CON (3.82 × 107CFU-TS,/,mg), but there was no statistical difference (p > 0.05) between CHX (168.88 mg) and CON (182.04 mg) masses nor statistical correlation (p > 0.05) between biofilm mass and CFU-TS,/,mg in the two groups. Conclusion,,, Chlorhexidine reduces the TS counts in TTBPE, but has no effect on biofilm mass. [source]


Biofilm Growth and Bed Fluidization in a Fluidized Bed Reactor Packed with Support Materials of Low Density,

ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 2 2004
R.A. Saucedo-Terán
Abstract Support materials of low-density for fluidized bed reactors provide several operational advantages, including lower energy requirements and proper biofilm growth balance. The aim of this investigation was to study the extent of biofilm growth and bed fluidization in an experimental reactor, using polyester resin (,pr,=,1220,kg/m3) and vitrified expanded perlite (,vep,=,1710,kg/m3) as alternative support materials to conventional silica sand. A noteworthy amount of biofilm was observed to be attached to both support materials from the very beginning of the bioreactor operation. Nevertheless, there were significant variations in biofilm growth and activity over the course of the experimental trials. For both perlite and polyester beds, the highest biofilm mass and the highest total number of mesophilic bacteria were observed between the 7th and the 10th day, showing a steady state trend at the end of the experimental runs. The chemical oxygen demand (COD) removal levels were concomitant with biofilm mass and total mesophilic bacteria changes, although the polyester bed efficiency was slightly higher than that for the perlite bed. As expected, the polyester bed was fluidized at a lower re-circulation flow compared to the perlite bed. Reactor back-washing was not required for these support materials since biomass excess was adequately separated by means of a special internal device. The efficiencies of removal of organic matter achieved were acceptable (up to 78,%) despite the low volume of the support material (25,%) and the low hydraulic retention time (30,min). [source]


Interaction between phosphorus and biodegradable organic carbon on drinking water biofilm subject to chlorination

JOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2010
S.-K. Park
Abstract Aims:, To examine whether phosphorus and biodegradable organic carbon interact to impact biofilm density and physiological function of biofilm-forming bacteria under conditions relevant to chlorinated drinking water distribution systems. Materials and Results:, The 2 × 2 factorial experiments with low and high levels of phosphorus and biodegradable organic carbon were performed on 4 -week-old drinking water biofilms in four separate pipe systems in the presence of chlorine. Experimental results revealed that biofilm heterotrophic plate count levels increased with the increase in biodegradable organic carbon concentration, showed no response to increases in levels of phosphorus and was not affected by interaction between phosphorus and biodegradable organic carbon. However, a significant positive interaction between phosphorus and biodegradable organic carbon was found to exist on biofilm mass and physiological function and/or metabolic potentials of biofilm communities; the effects of biodegradable organic carbon on biofilm mass and physiological function of biofilm-forming bacteria were accelerated in going from low to high level of phosphorus. Conclusions:, Biodegradable organic carbon was found to be the primary nutrient in regulating biofilm formation in drinking water regardless of the presence of chlorine. It can be therefore concluded that the removal of an easily biodegradable organic carbon is necessary to minimize the biofilm growth potential induced by the intrusion of phosphorus. Significance and Impact of the Study:, Phosphorus introduced to drinking water may interact with biodegradable organic carbon, thus leading to measurable impact on the biofilm formation. [source]


Effect of chlorhexidine mouth rinse on Streptococci counts of tooth-tissue-borne palatal expander biofilm

ORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 3 2008
IT Maruo
Structured Abstract Authors,,, Maruo IT, Rosa EAR, Maruo H, Tanaka O, Guariza Filho O, Ignácio SA, Camargo ES Objectives,,, To assess total Streptococci (TS) counts and biofilm mass over tooth-tissue-borne palatal expander (TTBPE), as well as the effect of chlorhexidine (CHX) mouth rinse on these variables. Design,,, A cross-sectional study design employed clinical procedures and laboratorial techniques. Setting and Sample Population,,, Patients who had TTBPE removal indicated were divided into two groups: a CHX group (n = 26) in which three times a day of 0.2% CHX digluconate mouth rinses were prescribed 7 days before TTBPE removal; and a control (CON) group (n = 25) in which no antimicrobial treatment was applied. Experimental Variable,,, ,Gender', ,Age', and ,TTBPE wear time' were recorded. After TTBPE removal, biofilm mass was determined by the difference between (TTBPE + biofilm) and (TTBPE only) masses. TS counts were determined by biofilm suspension followed by progressive dilutions and culture on Mitis Salivarius agar with incubation at 37°C for 72 h. Outcome Measure,,, Biofilm mass (mg) and Colony Forming Units of TS,/,mg of biofilm (CFU-TS,/,mg) were calculated. Results,,, Total Streptococci mean values in CHX (6.77 × 106CFU-TS,/,mg) were statistically lower (p < 0.01) than those in CON (3.82 × 107CFU-TS,/,mg), but there was no statistical difference (p > 0.05) between CHX (168.88 mg) and CON (182.04 mg) masses nor statistical correlation (p > 0.05) between biofilm mass and CFU-TS,/,mg in the two groups. Conclusion,,, Chlorhexidine reduces the TS counts in TTBPE, but has no effect on biofilm mass. [source]