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Abstract Background The increasing interest in probiotic lactobacilli in health maintenance has raised the question of potential risks. One possible side effect could be an increased acidogenicity in dental plaque. The aim of this study was to investigate the effect of probiotic lactobacilli on plaque lactic acid (LA) production in vitro and in vivo. Methods In the first part (A), suspensions of two lactobacilli strains (L. reuteri DSM 17938, L. plantarum 299v) were added to suspensions of supragingival dental plaque collected from healthy young adults (n=25). LA production after fermentation with either xylitol or fructose was analyzed. In the second part (B), subjects (n=18) were given lozenges with probiotic lactobacilli (L. reuteri DSM 17938 and ATCC PTA 5289) or placebo for two weeks in a double-blinded, randomized cross-over trial. The concentration of LA in supragingival plaque samples was determined at baseline and after 2 weeks. Salivary counts of mutans streptococci (MS) and lactobacilli were estimated with chair-side methods. Results Plaque suspensions with L. reuteri DSM 17938 produced significantly less LA compared with L. plantarum 299v or controls (p Conclusion Lactic acid production in suspensions of plaque and probiotic lactobacilli was strain-dependant and the present study provides no evidence of an increase in plaque acidity by the supply of selected probiotic lactobacilli when challenged by fructose or xylitol. The study protocol was approved by The Danish National Committee on Biomedical Research Ethics (protocol no H-2-2010-112). Trial registration NCT01700712

Objective. To evaluate the effect of chewing gums containing probiotic bacteria on oral malodour. The null hypothesis was that no difference would be displayed compared with placebo gums. Materials and methods. Twenty-five healthy young adults with self-reported malodorous morning breath completed this randomized double-blind placebo-controlled cross-over trial. The design included run-in and wash-out periods interspersed by two intervention periods of 14 days each. The subjects were instructed to chew one gum in the morning and one in the evening containing either two strains of probiotic lactobacilli ( L. reuteri DSM 17938 and L. reuteri ATCC PTA 5289) or placebo. The outcome measures were (i) organoleptic scores (0-5) by a certified test panel, (ii) concentration of volatile sulphur compounds (VSC) measured with a Halimeter and (iii) concentration of VSC after a cysteine rinse. Registrations were made at baseline and after each intervention period. Differences between the groups were assessed by non-parametric paired statistics and chi-square test. Results. The median organoleptic score was similar (score 2) in both groups at baseline. After 14 days of treatment, the organoleptic scores were significantly lower in the probiotic group compared with the placebo group ( p < 0.05). Assessments of the VSC levels displayed no significant differences between the groups, either before or after rinsing with L-cysteine. No adverse effects were registered. Conclusion. The results demonstrated that probiotic chewing gums may have some beneficial effect on oral malodour assessed by organoleptic scores. The results indicate that the probiotic gum may affect bacteria that produce malodourous compounds other than VSCs. [ABSTRACT FROM AUTHOR]

The aim was to compare the oral microbial profiles in young adults with an intake of free sugars above or below the current recommendations by the WHO for sugar consumption. Seventy subjects completed a Quantitative Food Frequency Questionnaire to establish the proportion of free sugars in relation to the total energy intake (% E). Subjects with <5% E (n = 30) formed the low-sugar group, while those with ≥5% E (n = 40) were regarded as reference group. Saliva and plaque samples were analyzed by qPCR, and 52 of the plaque samples were assayed by HOMINGS. The HOMINGSanalysis revealed a comparable core microbiota in plaque samples withStreptococcus,Leptotrichia,Actinobaculum, andVeillonellaas predominant. No major differences between groups were revealed by α-diversity testing (p = 0.83), principal component analysis, or correspondence analysis. Higher relative abundance ofStreptococcus sobrinusandPrevotella melaninogenicawas observed in plaque samples in the reference group. By qPCR,Scardovia wiggsiaewas associated with elevated sugar intake. The findings suggests that the amount of ingested sugars had a marginal influence on microbial profiles in dental plaque and saliva. However, some caries-associated species were less abundant in the dental plaque of the low sugar group. [ABSTRACT FROM PUBLISHER]