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Results for “DENTAL PLAQUE”

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At least 19 recordsLinked to original sources
PubMed1983

Biogenesis of methane in primate dental plaque.

Dental plaque samples collected from monkeys (Macaca mulatta) were found to contain a large amount of dissolved methane gas (0.6 nmol CH4/mg wet wt plaque). Enrichment cultures inoculated with dental plaque obtained from Macaca fascicularis produced methane when the medium contained ethanol, methanol, lactate, acetate or a hydrogen + CO2 atmosphere. Methane formation in the enrichments was inhibited by oxidation of the culture medium, autoclaving or the addition of 2-bromoethane sulfonic acid (BES). The methane producing enrichments were observed to contain fluorescent cocci occurring singly and in short chains. It was concluded that methane formation in the monkey dental plaque was the result of the presence of methanogenic bacteria.

Acetates↗
PubMedDate not supplied

Objective quantification method for measuring in vivo accumulated dental plaque.

Dental plaque was collected, dried, and weighed on a gold insert that fit into the buccal aspect of a posterior crown. The plaque weight was determined by calculating the difference between the postcollection insert weight and the precollection insert weight. This system for measurement of the dry weight of in vivo accumulated dental plaque was found to be a practical means of plaque quantification.

Adult↗
PubMed2004

The effect of xylitol chewing gum on mutans streptococci in saliva and dental plaque.

Dental caries are one of the most common infectious diseases occurred in Thai children. The chewing of xylitol, sorbitol, and even sugar gum has been suggested to reduce caries rates. The aim of the present investigation was to evaluate the effect of xylitol chewing gum on mutans streptococci (MS) in saliva and dental plaque. Ninety-one children, aged 10-12 years, with more than 1 x 10(5) MS per milliliter of saliva were included in this study. They were divided into three groups balanced according to their MS counts at baseline: one control group (no supervised gum use), and two xylitol groups (supervised 55% and 100% xylitol gum use). Whole saliva and pooled plaque samples were obtained after 90 school days. When comparing the MS counts between the groups, those chewing 100% and 55% xylitol gum showed significant reductions (p < 0.025), but a dose response effect was not demonstrated. Chewing 100% xylitol gum caused significant reductions on salivary MS scores (p < 0.025) which was little different from the 55% xylitol group. The results suggest that the use of xylitol chewing gum can reduce the levels of MS in plaque and saliva.

Chewing Gum↗
PubMed2006

Biofilms, a new approach to the microbiology of dental plaque.

Dental plaque has the properties of a biofilm, similar to other biofilms found in the body and the environment. Modern molecular biological techniques have identified about 1000 different bacterial species in the dental biofilm, twice as many as can be cultured. Oral biofilms are very heterogeneous in structure. Dense mushroom-like structures originate from the enamel surface, interspersed with bacteria-free channels used as diffusion pathways. The channels are probably filled with an extracellular polysaccharide (EPS) matrix produced by the bacteria. Bacteria in biofilms communicate through signaling molecules, and use this "quorum-sensing" system to optimize their virulence factors and survival. Bacteria in a biofilm have a physiology different from that of planktonic cells. They generally live under nutrient limitation and often in a dormant state. Such "sleepy" bacteria respond differently to antibiotics and antimicrobials, because these agents were generally selected in experiments with metabolically active bacteria. This is one of the explanations as to why antibiotics and antimicrobials are not as successful in the clinic as could be expected from laboratory studies. In addition, it has been found that many therapeutic agents bind to the biofilm EPS matrix before they even reach the bacteria, and are thereby inactivated. Taken together, these fundings highlight why the study of bacteria in the oral cavity is now taken on by studying the biofilms rather than individual species.

Bacteriological Techniques↗
PubMed1983

Stickland reactions of dental plaque.

Dental plaque samples from monkeys (Macaca fascicularis) were shown to contain proline reduction activity in coupled Stickland reactions with other amino acids and also with certain end products of bacterial glucose metabolism. The unusually high concentration of bound and free proline in the oral environment may be of importance in both the production of base and in the removal of acid from the tooth surface after dietary carbohydrate ingestion.

Amino Acids↗
PubMed1982

Extracellular iodophilic polysaccharide synthesized by Neisseria in human dental plaque.

Dental plaque collected from the label aspect of the anterior dentition of children harbored Neisseria that synthesized an extracellular iodophilic polysaccharide (EIP) from sucrose. Gas chromatograms of fully-acetylated EIP derivatives indicated that glucose (97%) and galactose (3%) were the only monosaccharide constituents present. The characterization of the partially-methylated alditol acetate (PMAA) derivatives of EIP indicated that it was primarily a linear 1,4 glucan (75.5%), with some 1,6 glucan (8.4%). The relative linearity of EIP (96.6%) as compared to that of amylose and glycogen was confirmed by spectrophotometric absorption studies.

Child↗
PubMed2000

Saliva and dental plaque.

Dental plaque is being redefined as oral biofilm. Diverse overlapping microbial consortia are present on all oral tissues. Biofilms are structured, displaying features like channels and projections. Constituent species switch back and forth between sessile and planktonic phases. Saliva is the medium for planktonic suspension. Several major functions can be defined for saliva in relation to oral biofilm. It serves as a medium for transporting planktonic bacteria within and between mouths. Bacteria in transit may be vulnerable to negative selection. Salivary agglutinins may prevent reattachment to surfaces. Killing by antimicrobial proteins may lead to attachment of dead cells. Salivary proteins form conditioning films on all oral surfaces. This contributes to positive selection for microbial adherence. Saliva carries chemical messengers which allow live adherent cells to sense a critical density of conspecifics. Growth begins, and thick biofilms may become resistant to antimicrobial substances. Salivary macromolecules may be catabolized, but salivary flow also may clear dietary substrates. Salivary proteins act in ways that benefit both host and microbe. All have multiple functions, and many do the same job. They form heterotypic complexes, which may exist in large micelle-like structures. These issues make it useful to compare subjects whose saliva functions differently. We have developed a simultaneous assay for aggregation, killing, live adherence, and dead adherence of oral species. Screening of 149 subjects has defined high killing/low adherence, low killing/high adherence, high killing/high adherence, and low killing/low adherence groups. These will be evaluated for differences in their flora.

Anti-Bacterial Agents↗
PubMed2001

In situ study of sucrose exposure, mutans streptococci in dental plaque and dental caries.

The purpose of this study was to investigate the relationship among frequency of sucrose exposure, mutans streptococci levels and dental caries. Adult volunteers took part in this crossover study performed in 4 phases of 28 days each. The volunteers wore intra-oral palatal appliances containing blocks of human dental enamel and dripped 20% sucrose solution onto the dental blocks from 0 to 8 times/day. After each phase, the colony forming units (CFU) were determined in dental plaque and enamel dental caries was evaluated using cross-sectional hardness. Sucrose frequency had no statistically significant effect on mutans streptococci levels. In the enamel cross-sectional hardness tests, significant differences (p < 0.05) in relation to area of mineral loss were observed only when sucrose exposure was 8 times/day. Similar results were obtained when cross-sectional hardness was assessed at each distance from enamel surface.

Adult↗
PubMed1999

Microbiologic aspects of dental plaque and dental caries.

Dental plaque is an example of a microbial biofilm with a diverse microbial composition; it is found naturally on teeth and confers advantages to the host, for example, by preventing colonization by exogenous, and often pathogenic, micro-organisms. In individuals with a high frequency sugar diet, or with a severely compromised saliva flow, the levels of potentially cariogenic bacteria (acid-producing and acid-tolerating species) can increase beyond those compatible with enamel health. This article discusses antimicrobial strategies to control dental caries, including; reducing plaque levels, in general or specific cariogenic bacteria in particular, by antiplaque or antimicrobial agents; reducing bacterial acid production by replacing fermentable carbohydrates in the diet with sugar substitutes, or by interfering with bacterial metabolism with fluoride or antimicrobial agents.

Anti-Bacterial Agents↗
PubMed1976

Correlation between streptococci of human dental plaques and dental caries.

Plaque samples from 27 buccal tooth surfaces were obtained with sterile McCall curettes from available third molars. Bacteriological sampling and biochemical tests were carried out to identify four groups of streptococci, i.e. Str. mutans, Str. spp., Str. sanguis and Str. mitis. Clinical examinations carried out 6 months after the dental scrapings were taken showed a strong positive correlation between detectable lesions and Str. mutans.

Dental Caries↗
PubMed1987

Relationship between dental plaque indices and bacteria in dental plaque and those in saliva.

A variety of indices has been developed for the quantitation of dental plaque. The aim of this study was to determine the correlation between the Löe plaque index and the number of bacteria on the same tooth. Furthermore, the effect of plaque accumulation on the salivary counts of some dental plaque organisms was estimated. Twenty volunteers were asked to abstain from all oral hygiene for a one-week period. Clinical indices and bacteriological samples were taken at the start and at the end of the experimental period. After an interval of seven days, the experiment was repeated. The relationship between the Löe plaque index and the total bacterial counts on the same area of the tooth was found to be highly significant. After seven days without oral hygiene, the total counts and the Actinomyces viscosus/naeslundii and Streptococcus sanguis counts in dental plaque had increased by approximately two log units, while the Streptococcus mutans counts had increased by more than one log unit. The large increase in the number of bacteria on the teeth was reflected in the salivary counts of the Actinomyces species, but not in the S. sanguis or S. mutans counts. This was due to differences in ecological habitats of these species in the mouth. Highly significant correlations were found between the S. mutans level in dental plaque and the salivary level, and between the S. mutans counts of the subjects in the first and second trials of the experiment.

Actinomyces↗