BACKGROUND Mutans streptococci (Streptococcus mutans and S. sobrinus) are considered to be major etiologic agents of dental caries. Using a polymerase chain reaction method, we detected those bacteria from 145 outpatients (6-30 years old) with intellectual disabilities (ID) and their presence was compared with the incidence of dental caries. METHODS Plaque samples were collected from all erup...

A more sensitive test agar was developed to detect oral microbes with relatively low dextranase activity and to identify dextranase-negative mutants. Several oral streptococci that had previously been scored as dextranase negative readily decolorized the new, blue dextran-containing medium. To assess whether dextranase plays a role in glucan synthesis by oral streptococci, various glucan synthe...

The inhibitor), effect of hop bract polyphenols (HBP) on cariogenic streptococci was investigated. It wu'as fbund that the high molecular weight polyphenol (estimated about 36,OeO-40,OOO) inhibited the cellular adherence of Streptoeoccus mutans MT8148 (serotype C) and Streptoeoeeus sobrinus ATCC 33478 (serotype g) at msuch smaller concentrations than the polyphenols extracted from oe)ong tea or...

The extracellular dextrans produced from sucrose by Streptococcus mutans strains BHT and GS-5 did not prevent the synthesis or release of active bacteriocins by these two strains. In addition, several streptococci that were genetically sensitive to these bacteriocins, and that could synthesize a variety of extracellular dextrans and levans from sucrose, remained phenotypically sensitive when gr...

Despite the use of conventional physical and chemotherapeutic agents for caries management, dental caries still continues to be the most prevalent oral infectious disease. Thus, there is a need of additional caries prevention approaches. Strain replacement therapy is one such novel approach. In this, relatively avirulent strains of Streptococcus mutans produced by recombinant DNA technology are...

Dental caries on population presents a tremendous challenge to the dental profession in population. In the attempt to lower the sugar consumption in population is to exchange the number of sugar sweeteners which manufacture produced for used in foods, drinks and candy with non-sugar sweetener as sorbitol. Sorbitol is effective as non cariogenic substitutes for use in place of glucose. Objective...

A group of streptococci possessing the characteristics of Streptococcus miteor (S. mitis) was found to predominate on nonkeratinized human oral mucosa. These organisms averaged from 76 to 89% of the total flora cultivable on anaerobically incubated blood agar plates from cheek, lip, and ventral tongue surfaces. They averaged 34, 40, and 18% of the streptococci in dental plaque, in saliva, and o...

In Streptococcus mutans, the global response regulator CovR plays an important role in biofilm formation, stress-tolerance response, and caries production. We have previously shown that CovR acts as a transcriptional repressor by binding to the upstream promoter regions of its target genes. Here, we report that in vivo, CovR activates the transcription of SMU.1882, which encodes a small peptide...

Flavonoids have been considered the main biologically active components in propolis. However, a new variety of flavonoid-free propolis was recently found and chemically classified as type 6. Because it showed activity against oral microorganisms, this study evaluated the effects of the crude ethanolic extract of this propolis and its chemical fractions on the activity of purified glucosyltransf...

The objective of this study was to evaluate the bacterial profile in root canals of human primary teeth with necrotic pulp and periapical lesions using bacterial culture. A total of 20 primary teeth with necrotic pulp and radiographically visible radiolucent areas in the region of the bone furcation and/or the periapical region were selected. After crown access, 4 sterile absorbent paper points...