Criteria for the assessment of adverse effects of chemotherapy on the oral microflora.

Any assessment of an antimicrobial agent for the prevention of dental caries must include a consideration of its possible adverse effects on the oral flora. It must include an examination of the resistance developed by the target pathogens and either developed by, or inherently present in, microorganisms that are known to cause opportunistic infections (yeasts, enteric organisms, Pseudomonas, clostridia, and Staphylococcus aureus). Streptococcus pyogenes should also be included.

Biotin-containing protein as a cause of false positive clones in gene probing with streptavidin/biotin.

Using a streptavidin/biotin labeling technique, we unintentionally cloned a gene encoding a biotin carboxyl carrier protein, a subunit of biotin-dependent enzymes, from a genomic library of Streptococcus mutans strain UT-041. In colony lifts, the clone reacted positively to the streptavidin-containing detection system but could not be detected in Southern blot analysis. The amino acid sequence of the gene product, deduced from its nucleotide sequence, demonstrated all the features common to biotin carboxyl carrier proteins from other bacteria, indicating that the biotin carboxyl carrier protein in the clone had produced a "false-positive" (DNA probe-independent) reaction by binding to the streptovidin.

The effect of chlorhexidine varnish treatment on salivary mutans streptococcal levels in child orthodontic patients.

A chlorhexidine dental varnish was applied to the teeth of 26 children, ten to 17 years of age, in an attempt to limit the increase in colonization by mutans streptococci that normally accompanies the placement of fixed orthodontic appliances and to assess the acceptance of the application procedure. Despite the insertion of the appliances in the month following the varnish application, the numbers of detectable salivary mutans streptococci in the children were found to remain significantly lower than baseline values for seven months (p less than 0.01).

Clinical trial in adults of an antimicrobial varnish for reducing mutans streptococci.

An abbreviated treatment with a chlorhexidine-containing varnish was compared with a similar treatment with a placebo varnish and with a prophylaxis alone for its effects on the numbers of detectable salivary mutants streptococci in 51 adults. The varnishes, applied once weekly for four weeks, were held in place with a covering layer of either of two polyurethane sealants (FluorProtector or Adhesit). On the first appointment, the varnish-sealant combination was applied to all tooth surfaces, but on succeeding appointments only the occlusal and approximal surfaces were covered.

Changes in strains of mutans streptococci induced by treatment with chlorhexidine varnish.

Isolates of mutans streptococci were obtained from the dental plaque of ten subjects before and after the subjects had been free of detectable mutans streptococci for a mean period of 14.6 weeks (range, from two to 36 weeks). The mutans streptococci had been rendered undetectable by chlorhexidine varnish treatment.