Comparison of culture media and chairside assays for enumerating mutans streptococci.

AIM: This study compared several traditional culture-based media and chairside cultural assays for ability to recover mutans streptococci (MS) from pure cultures and from saliva samples. METHODS AND RESULTS: When pure cultures were used with traditional culture-based media, mitis-salivarius bacitracin (MSB) agar demonstrated less support for bacterial recovery than trypticase-yeast extract-cysteine sucrose-bacitracin (TYCSB) agar and the modified medium of Ritz (HLR-S). One species of MS, Streptococcus ferus (c), was not recovered on MSB medium. Chairside cultural tests displayed considerable disparity between tests in recovering bacteria from pure cultures. On the glass adherence assay (Mucount), S. ferus was not detected and Streptococcus criceti was not detected on the dipslide assay (Cariescreen SM) or on the plastic adherence assay (Dentocult SM Strip mutans). The frequency of isolation of pure strains of bacteria other than MS was common. From saliva samples, the frequency of isolation of MS on HLR-S and TYCSB media and the glass adherence assay was 91-97%. The frequency of isolation on MSB medium and on the dip-slide and plastic adherence assays was significantly decreased (37, 47 and 69%, respectively). Recovery scores varied considerably among the culture methods studied and tended to be highest on the HLR-S medium and on the glass adherence assay. CONCLUSIONS: Growth and recovery profiles of pure bacterial cultures and of saliva samples for the MS varied according to different media. SIGNIFICANCE AND IMPACT OF THE STUDY: Caution should be exercised in comparing results between studies that employ different cultural methods for MS enumeration.

Maintaining mutans streptococci suppression with xylitol chewing gum.

BACKGROUND: One strategy for treating dental caries is to suppress oral mutans streptococci, or MS, with chlorhexidine, or CHX, mouthrinse. Oral MS levels, however, tend to quickly return to baseline values without further intervention. In this clinical study, the authors evaluated the effect of xylitol chewing gum on MS regrowth. METHODS: The authors selected 151 subjects with elevated oral MS levels (> or = 105 colony-forming units per milliliter, or CFU/mL, of paraffin-stimulated saliva). Subjects rinsed with 0.12 percent CHX gluconate mouthrinse twice daily for 14 days. The authors then randomly assigned the subjects to one of three groups. Those in the test group (n = 51) chewed a commercial xylitol gum three times daily for a minimum of five minutes each time for three months. The placebo group subjects (n = 50) used a commercial sorbitol gum, and the control group subjects (n = 50) did not chew gum. The authors estimated MS load on the dentition using paraffin-stimulated saliva samples. The authors serially diluted the samples, plated them on selective media and incubated them anaerobically; they then enumerated the colonies under a stereomicroscope. RESULTS: MS levels were not significantly different between the three groups at baseline (mean log CFU/mL +/- standard deviation: 5.4 +/- 0.7, 5.4 +/- 0.8, 5.2 +/- 0.7, respectively) nor after CHX therapy (2.7 +/- 0.8, 3.1 +/- 1.1, 3.0 +/- 1.1, respectively). After three months of gum chewing, the test group subjects had significantly lower salivary MS levels (3.6 +/- 1.2) than did the placebo (4.7 +/- 1.2) or control (4.4 +/- 1.3) group subjects. CONCLUSIONS: Xylitol chewing gum appears to have the ability to prolong the effect of CHX therapy on oral MS. CLINICAL IMPLICATIONS: Maintaining long-term caries-pathogen suppression is feasible with currently available commercial products and can be expected to result in significant caries inhibition.

Effect of chlorhexidine varnish mouthguards on the levels of selected oral microorganisms in pediatric patients.

PURPOSE: The effect of a chlorhexidine varnish delivery system on the levels of selected oral microorganisms was evaluated in caries active pediatric patients, ages 4 to 12 years old. METHODS: Forty-six patients were enrolled into the study when they had multiple carious surfaces and salivary mutans streptococci (MS) levels higher than 10(4) colony forming units (CFUs) per milliliter. This study incorporated a double-blind design and patients were randomly assigned to either the chlorhexidine treatment group or the placebo group. Complete-arch, vacuum-adapted mouthguards (0.02 in. polypropylene coping material) were custom fabricated and coated internally with either a 3.0% chlorhexidine varnish or a placebo varnish. Two pretreatment paraffin-stimulated saliva samples were obtained for culturing prior to varnish treatment. Saliva samples were also obtained immediately after treatment and once a month for up to three months after wearing the mouthguard appliances. Dental restorations were placed at most of these saliva collection visits. Mouthguards were reportedly worn for an average of 9.7 hours per night for approximately seven nights by 40 subjects (87%). RESULTS: After two months, and after three months, there was a significant reduction in MS levels immediately after the chlorhexidine varnish treatment. Total anaerobic and total facultative bacteria levels were not significantly affected. CONCLUSION: One week of nightly use of the chlorhexidine varnish mouthguard system is effective at reducing the number of MS in caries-active pediatric patients in the mixed and primary dentition for at least three months.

Functional units, chewing, swallowing, and food avoidance among the elderly.

PURPOSE: The number of teeth in the dentition was compared with the number and types of dental functional units (opposing tooth pairs) to correlate the number of functional units with complaints about chewing and swallowing in the elderly. MATERIAL AND METHODS: Complaints of oral pharyngeal function and food avoidance practices were compared with the number and types of functional units. A convenience sample of 602 elderly subjects (468 men, 134 women, mean age 70 years) were interviewed and examined dentally. RESULTS: Functional unit measures, which included functional arrangement of the teeth and the number and type of teeth present, were found to be more discriminatory and descriptive of masticatory potential than the more number of teeth. Elderly persons (> or = 60 years of age) with reduced numbers of functional units tended to report difficulty chewing, avoidance of stringy foods (including meat), crunchy foods (including vegetables), and dry solid foods (including breads), and difficulty in swallowing. Removable prostheses did not appear to prevent these consequences and, at least in this elderly population, did not appear to be equivalent to natural teeth in terms of masticatory potential. CONCLUSIONS: It is possible that compromised dental function results in the swallowing of poorly chewed food, food avoidance patterns, dietary inadequacies, and systemic changes favoring illness, reduced vigor, debilitation, and shortened life expectancy. Emphasis should be placed on maintaining natural teeth whenever possible.

Effect of repeated treatment with sustained-release chlorhexidine mouth guards on salivary levels of mutans streptococci.

The effect of multiple treatments with chlorhexidine mouth guards on salivary levels of mutans streptococci (MS) was studied. Eleven subjects with salivary MS > or = 10(5) CFU/ml were randomly assigned to an experimental or control group. Complete-arch mouth guards were coated internally with one of two ethylcellulose varnishes, one containing 30% dry w/w chlorhexidine and one containing no chlorhexidine. Subjects wore the mouth guards up to four times, each time for 7 consecutive nights while sleeping, with at least a 1-week break between treatment weeks. Subjects in the control group subsequently crossed over and also wore the chlorhexidine-containing mouth guards. Each of the week-long mouth guard sessions resulted in a reduction in mean salivary MS levels as follows (log10 CFU/ml): for the experimental group, -1.0, -0.9, -1.0 and -1.2, and for the crossover group, -1.7, -0.6, -0.5 and -0.6. Salivary MS levels were (mean +/- SD) 6.4 +/- 0.5 at baseline and 3.8 +/- 0.5 after the last mouth guard session for the experimental group and 6.0 +/- 0.5 and 4.3 +/- 0.7, respectively, for the crossover group. For the control group, there was no significant change in MS levels.

Dental findings in geriatric populations with diverse medical backgrounds.

OBJECTIVE: To determine whether there is a difference in the oral/dental health in older persons with different life styles and medical status. STUDY DESIGN: Survey (cross-sectional study) included four groups: (1) subjects (n = 123) living in a residential retirement home or community dwelling; (2) subjects (n = 218) seeking dental treatment at a Veterans Affairs Dental Outpatient Clinic; (3) subjects (n = 132) resident in a VA long-term care facility; and (4) subjects (n = 81) recently admitted to a VA acute care ward with a diagnosis of cerebral vascular accident or other neurologic problem. Each subject answered questions on medical and dental health and dietary preferences in a comprehensive interview. They were given a comprehensive dental examination that included measurements of stimulated salivary flow and minor salivary gland output. RESULTS: The data from groups 2 and 3 confirmed previous reports that independent living subjects have better oral/dental health than dependent living subjects. The data from groups 1 and 4, obtained from geriatric populations on the opposite ends of the medical health/disease continuum provide new information that suggests that good medical health and good oral/dental health are linked. The subjects in group 1 were very healthy as judged by their longevity; 54% were > or = 80 years and they had low reported prevalence of medical disease. Only 6% were edentulous and the dentate persons were missing 4.5 teeth. In contrast, over 50% of the patients in group 4 were < 70 years; they had an edentulous rate of 49% and among the dentate persons had an average 12 missing and 5 decayed teeth. CONCLUSIONS: The medically healthy persons had excellent dental health whereas the sickest persons were either edentulous or had many missing teeth.

Comparison of the number and type of dental functional units in geriatric populations with diverse medical backgrounds.

Elderly subjects (N 430) from four convenience populations that represented different levels of medical health--independent living (Veterans Affairs and non-Veterans Affairs), nursing home, and hospitalized acute care--were given dental examinations. The independent living groups had significantly higher numbers of functional units (opposing natural or prosthetic tooth pairs) and of contiguous functional units compared with the nursing home and hospitalized groups. There was a shift from functional units that consisted of natural teeth to functional units that consisted of prosthetic teeth in the nursing home and hospitalized groups. Numbers of functional units were negatively correlated to plaque index, papillary bleeding scores, and minor salivary gland output. This study suggests a strong relationship between functional integrity of the dentition and general health.

Effect of slow-release chlorhexidine mouthguards on the levels of selected salivary bacteria.

This study evaluated the effect of an alternate delivery system for chlorhexidine on salivary levels of mutans streptococci (MS) and other selected oral bacteria. On the basis of salivary MS levels > or = 10(4) CFU/ml, 22 subjects were enrolled. All caries lesions were restored prior to treatment. Two pretreatment paraffin-stimulated saliva samples were obtained for culturing at least 1 week apart. Complete-arch vacuum-adapted mouthguards were individually fabricated and coated internally with a 3% w/v chlorhexidine varnish. Mouthguards were worn for an average of 7 h/night for 7 nights. Saliva samples were obtained immediately after treatment and 1 and 3 months later. There was no significant change in levels of any of the monitored bacteria between the two pretreatment samples. A significant and specific reduction in salivary MS levels was observed in the three after-treatment samples as compared with baseline values (p < 0.001, p < 0.001, p < 0.05, respectively). The levels of Actinomyces viscosus were also measured, and there was a significant reduction immediately after treatment (p < 0.05), a return to baseline values at 1 month, and a significant increase above baseline values at 3 months, (p < 0.001). There was no significant change in saliva volume, in total numbers of facultatively anaerobic bacteria, or in levels of lactobacilli or Streptococcus sanguis. This treatment system is capable of significant and specific suppression of MS levels for up to 3 months without retreatment.