Distribution of mutans streptococci in families: a longitudinal study.

The purpose of this study was 1) to investigate whether a group of children not colonized by mutans streptococci (MS) at the age of 3 years were colonized several years later, and 2) to study whether MS that appeared in the children were identical to those found in the parents. In a previous study no MS were found in 13 3-year-old first-born children. In 10 of these children pooled plaque samples were again collected after 5 years, and in the other 3 children after 2 years. Additionally, separate plaque samples were obtained from the children's first permanent molars when the teeth were present. Pooled samples were also obtained from all the parental pairs at follow-up and from three pairs at baseline. MS were isolated, and genotyping was done through DNA fingerprinting by restriction endonuclease analysis. In 10 children MS were still not found. Among the three children with detectable MS the DNA fingerprints of the bacteria were the same in one girl and her mother and in one boy and his father; in the other boy no similar pattern was found in either mother or father. None of the individuals in the 13 parental pairs showed identical genotypes of MS. The results indicate an opportunity to remain MS-negative if not colonized at the age of 3 years. The difficulty of being colonized with MS from the spouse is highlighted.

Differentiation of Streptococcus mutans and Streptococcus sobrinus via genotypic and phenotypic profiles from three different populations.

Routine identification of Streptococcus mutans and Streptococcus sobrinus is generally based upon growth on various selective media, colony morphology and biochemical characteristics. We examined various approaches of differentiating these two species through a combination of the conventional phenotypic methodology with chromosomal DNA fingerprint (CDF) and arbitrarily primed polymerase chain reaction (AP-PCR) methods. Initially, ten ATCC type strains and 20 randomly selected clinical isolates of mutans streptococci (MS) were characterized and grouped into two major types based on patterns generated by the CDF using HaeIII digestion. The CDF's patterns with restriction fragments equal to or greater than 6.6 kb were defined as the CDF-1 group. The CDF's patterns with restriction fragments less than 6.6 kb were defined as the CDF-2 group. Both groups were then examined for biotype, serotype, and composition of DNA via thermal denaturation. AP-PCR was applied and evaluated for the capability of delineating S. mutans from S. sobrinus strains. Results of this study showed that all CDF-1 strains fit within a G+C range of 36.2% to 42.2%, whereas the CDF-2 strains had a G+C range of 45.8% to 47.0%. The serotyping assay exhibited 100% sensitivity, 90% specificity and 86.7% agreement with the CDF. The biotyping assay presented the poorest specificity (38.5%), indicating the highest variability. The capability of AP-PCR in differentiation of S. mutans from S. sobrinus was comparable to the CDF method, suggesting that either of these two approaches can and may serve as a viable alternative method to serotyping or biotyping of MS.

Genotypes of mutans streptococci tend to persist in their host for several years.

The aim of this study was to evaluate the consistency of the prevalence of mutans streptococci in a group of Swedish families. Eleven families, which had previously been examined for genotypes of mutans streptococci, were re-examined after 2-5 years. The families consisted of mother, father and a child (mean age 7.2 years at the follow-up examination). One father did not participate. Pooled plaque samples were obtained from buccal and occlusal surfaces. Isolates of mutans streptococci were genotyped using chromosomal DNA digested with restriction endonuclease HaeIII, separated by gel electrophoresis and visualised through UV illumination after ethidium bromide staining. Comparing the DNA fingerprints of mutans streptococci found at baseline and follow-up, 9 children harboured one or two genotypes which were similar on the two sampling occasions. Two of these children had also gained a genotype. The remaining 2 children had lost a genotype each and 1 of them had gained two new genotypes. All 21 adults showed one or two genotypes identical to those found at baseline. Nine of these 21 adults had also lost one genotype. Four of these 9 and additionally 4 of the remaining adults showed one or two new genotypes. Six mother-child pairs shared a genotype at baseline and this pattern remained for five pairs at the end of the study. The results suggest that genotypes of mutans streptococci have a fairly high degree of consistency in children between 3 and 8 years of age as well as in adults, indicating persistence of the strains. However, the results also indicate that some subjects may gain and/or lose genotypes.

Oral retention of glucose at pharmacologically reduced salivary flow in man.

The aim was to study the influence of mouthrinses with glucose, at concentrations ranging from 1 to 50%, on oral retention at two different locations in the oral cavity. Salivary secretion was reduced in 10 subjects by injection of methylscopolamine nitrate submucosally. The volunteers were randomly assigned to rinse with 10 ml of either 1%, 10%, or 50% glucose solution for 30 s, after which measurements of glucose concentration and parotid salivary secretion rate were performed during a 10-min period. The results showed higher salivary glucose levels vestibularly than sublingually. The difference in glucose retention between the two locations increased when the salivary flow rate recovered. The relationship between secretion rate and area under the curve for glucose measured sublingually, but not in the vestibule, was bilinear.

An individual training programme for speeding up prolonged oral sugar clearance in hospitalized elderly patients. A pilot study.

The aim of this pilot study was to evaluate an individual programme for speeding up prolonged oral sugar clearance in hospitalised elderly patients. Six patients at a university hospital for geriatric medicine, aged 67-85 years, completed a 6-week study. Every second week one of the authors gave: 1) information on the importance of oral sugar clearance for oral health, 2) instruction in oral hygiene, and 3) professional tooth cleaning. Moreover, the staff responsible for each patient provided 1) massage and training of the lips, cheeks and tongue shortly before each main meal, 3 times daily, 2) supervision of chewing on a sugar-free chewing gum for at least 20 min, 4 times daily, and 3) support and encouragement of the patients throughout the day. Salivary glucose clearance was measured both sublingually and vestibularly in the lower jaw after chewing a glucose tablet and after a mouth rinse with 10% glucose solution. There was a clear tendency that the oral sugar clearance was reduced after the 6-week period and some of the reductions in the clearance variables were statistically significant. All patients, especially those suffering from cerebral haemorrhage, reported an improved ability to chew while proceeding with the programme, which was also confirmed by the staff. The main conclusion from this pilot study is therefore that it might be possible to speed up prolonged oral sugar clearance in elderly hospitalised patients using an individual training programme.