A randomized clinical trial of the effect of yoghurt on the human salivary microflora.

Yoghurt is active against some human pathogens, so this experiment tested whether it is also active against the salivary microflora. A clinical trial was designed, with volunteers aged between 23 and 37 years. Initially, for 8 weeks, they consumed neither yoghurt nor casein-free soybean ice cream (phase 1). They were then split randomly into test (yoghurt) and control (ice cream) groups and required to consume 125 g of these foods twice daily for 8 weeks (phase 2) and then to avoid them for the following 2 weeks (phase 3). Many potential sources of microbial fluctuation were standardized. Salivary samples were then collected at regular intervals of 2 weeks. For each group and phase, the mean logarithms of the salivary counts for total viable flora, oral streptococci, mutans streptococci, lactobacilli and Candida were calculated. The prevalence of Streptococcus thermophilus and Lactobacillus bulgaricus was also assessed. Twenty test and 22 control participants completed the study. At phase 2, the mean for mutans streptococci was lower in the test than in the control group (3.6 vs. 4.0 log colony-forming units/ml; P=0.02). Moreover, the mean had decreased in all test participants with high phase 1 means for lactobacilli as compared to only 36.4% of those with low phase 1 means (P=0.01). L. bulgaricus was transiently detected in three test participants during phase 2. These results suggest that yoghurt does have some activity against the salivary microflora, but this does not seem to be due to the installation of yoghurt microorganisms in the mouth.

Restoration-related salivary Streptococcus mutans level: a dental caries risk factor?

OBJECTIVES: The salivary level of Streptococcus mutans related to filled teeth was compared with the levels related to decayed and sound teeth, in order to establish whether the presence of restorations may increase the risk of infection of other teeth by Streptococcus mutans. METHODS: The sound, decayed and filled teeth were recorded in 809, 6-7-year-old school-children. Salivary Streptococcus mutans detection (i.e. more than 1 x 10(4) CFU/ml) and counts were evaluated. Streptococcus mutans log count means and prevalence values of subjects with only sound teeth (group 1), with filled, without decayed teeth (group 2), with decayed, without filled teeth (group 3), were calculated and compared using the Student's t-test and the chi-square test. The effect of filled, decayed and sound teeth on Streptococcus mutans level was also evaluated using logistic regression. RESULTS: Log count means and prevalence values of group 2 subjects were significantly lower than values of group 3 subjects (means, 0.92 vs 1.66: prevalence, 73.17% vs 94.63%) and statistically not-different from values of group 1 subjects (mean. 0.75: prevalence, 70.06%). The logistic regression analysis showed that the factors significantly increasing the risk of Streptococcus mutans being detected in saliva were only primary and/or permanent decayed teeth. The risk of Streptococcus mutans being detected in saliva was not affected by filled teeth more than sound teeth. CONCLUSIONS: In the present study population, the salivary Streptococcus mutans level attributable to filled teeth was low; this suggests that treatment of a carious lesion would cause a lowering of Streptococcus mutans concentration to the same levels as those shown by healthy subjects, thus reducing the risk of infection to other teeth.

[Dental health and the state of oral hygiene in an elderly population in Rome]. / La salute dentale e i comportamenti di igiene orale in una popolazione anziana di Roma.

The purpose of this study was to investigate dental conditions and oral hygiene in a population of 369 elderly people residing in Rome--293 females and 76 males--aged between 60 and 99 years (mean 81.9 +/- 8.1). The sample was interviewed following a dental examination. Clinical tests revealed that 40% were totally edentulous, whereas subjects with natural teeth had a mean of 11.4, teeth, of which 1.5 were decayed. Oral hygiene habits were investigated by means of questions on use of dental tools (toothbrush, mouth-wash, dental floss), which were not much used. Moreover, many elderly people reported they had not been to the dentist's recently (86.2% during the last year) because they did not feel it necessary. From this study a rather low level of oral health has emerged, along with a limited knowledge of prevention for dental and periodontal diseases. These results show the need of dental treatment and prevention for the elderly population.

[A new device for the disinfection of handpieces and turbines]. / Su un nuovo apparecchio per la disinfezione di manipoli e turbine.

Dental handpieces are often difficult to disinfect. This is one of the main reasons for the considerable risk of cross-infections in dental offices. The aim of the present study was the evaluation of the disinfectant property of a recent, commercially available, automatic instrument, described as capable to clean, disinfect and lubricate dental handpieces. The following experimental evaluations were made: 1) antimicrobial activity of the disinfectant (glyoxalaldehyde) used. The method described by the European Committee for Standardization was followed. Test microorganisms were Pseudomonas aeruginosa and Staphylococcus aureus. 2) disinfection of dental handpieces (69 contra-angles and 97 turbines of different marks). They were naturally infected using them on patients for 30 minutes at least. 3) disinfection of dental handpieces infected with bacterial suspensions of Staphylococcus aureus, Streptococcus pyogenes (beta-haemolyticus, group A), Candida albicans and Pseudomonas aeruginosa. The results of the first experiment showed a strong bactericidal power of the disinfectant with both the tested strains, after a contact time of only 1 minute. A great proportion of the dental handpieces tested during the second experiment were found disinfected: from 84% through 89% out of the various models of turbine handpieces; from 89% through 100% out of the models of contra-angle handpieces. Even though bacterial contamination level was low (about 10(3) microorganisms per handpiece), a satisfactory disinfectant ability in natural conditions was found. The results of the third experiment were unclear. The tested instrument reduced 10(5)-10(8) times the original bacterial count when the gram positive microorganisms (Staphylococcus aureus, Streptococcus pyogenes) were used. On the other hand, when Pseudomonas aeruginosa and Candida albicans were used, the results were different: the bacterial count was reduced 10(6)-10(7) times in some cases, and only 10(2) times in other cases. This difference was found in the tests made using the same attachment and in those made using various attachments. In conclusion, the tested instrument showed, in most cases, a good disinfectant property, but the presence of unclear results suggests that some technical modifications are required.