Probiotics for managing caries and periodontitis: Systematic review and meta-analysis

Abstract

Objectives

Probiotics might be beneficial to prevent or treat caries, gingivitis or periodontitis. We aimed to appraise trials assessing probiotics for managing caries and periodontal disease.

Data

We included randomized controlled trials comparing the efficacy of probiotics versus (placebo) control with regards to Streptococcus mutans [SM], lactobacilli [LB], periodontal pathogens numbers, gingivitis, oral hygiene, caries incidence/experience increment, or periodontitis. Meta-analysis and trial-sequential-analysis were performed.

Sources

Three electronic databases (Medline, Embase, Central) were screened.

Study selection

50 studies (3247 participants) were included. Studies were mainly performed in children and used lactobacilli (45); bifidobacteria (12) or other genus (3). Probiotics significantly increased the chance of reducing SM (OR: 2.20, 95% CI: 1.23/3.92) or LB (OR: 2.84; 1.34/6.03) <10⁴ CFU/ml. Such reduction was confirmed for SM counts (standardized mean differences: −1.18, 95% CI: −1.64/-0.72), but not LB (SMD: 0.33; 0.15/0.52). For periodontal pathogens, no significant difference was found. Probiotics significantly reduced bleeding-on-probing (SMD: −1.15; −1.68/-0.62) and gingival index (SMD: −0.86; −1.52/-0.20), but not plaque index (SMD: −0.34; −0.89/0.21). Caries incidence was not significantly reduced (OR: 0.60; 0.35/1.04), neither was caries experience (SMD: −0.26; −0.55/0.03) or CAL (SMD: −0.46; −0.84/0.08). In contrast, probing-pocket depths (SMD: −0.86; −1.55/-0.17) were significantly reduced. Data was quantitatively insufficient for conclusive findings, and risk of bias was high.

Conclusion

Current evidence is insufficient for recommending probiotics for managing dental caries, but supportive towards managing gingivitis or periodontitis. Future studies should only record bacterial numbers alongside accepted disease markers or indicators.

Clinical significance

Probiotic therapy could be used for managing periodontal diseases. For caries, further studies should ascertain both efficacy and safety.

Introduction

Probiotics are defined as “live microorganisms which, when administered in adequate amounts, confer a health benefit on the host” [1]. Currently, antibacterial effects (e.g. via co-aggregation, toxic by-products or competition for substrates), stabilization of the flora and modulation of the host’s immune system are thought to provide these benefits. A range of bacteria (most of them being acidogenic like lactobacilli, streptococci or bifidobacteria) have been suggested to exert one or more of these effects [2], [3], [4].

Probiotics might be beneficial to prevent or treat oral diseases like caries, gingivitis or periodontitis, which are associated with a shift in the bacterial biofilm composition and activity as well as subsequent host reactions. Potential effects of probiotic species on cariogenic or periodontal pathogens have been abundantly demonstrated in vitro [5], [6], [7], [8], [9], [10]. Clinically, alterations of surrogate markers like bacterial numbers have been used to argue for the benefits of probiotic therapy. Only few studies, however, have used indicators of the diseases themselves (increment of newly developed caries lesions or caries experience; probing-pocket depths or clinical attachment loss) to prove the efficacy of probiotics for preventing or treating caries or periodontitis [11], [12], [13], [14], [15]. Moreover, some studies even claim probiotics to not have beneficial, but potentially harmful effects [9], [16], [17].

Recent systematic reviews in the field have either qualitatively summarized selected studies on either caries [3] or periodontitis [18], or meta-analyzed available surrogate markers [19]. No study so far has attempted to comprehensively display the available evidence from randomized controlled trials on effects and efficacy of probiotics on both caries and periodontal disease using both qualitative and quantitative synthesis. Moreover, no study investigated potential causes for heterogeneity between studies, i.e. assessed the role of potential effect modifying variables. The present study aimed to systematically review and synthesize available randomized controlled studies investigating effects of probiotics on oral caries or periodontal disease (gingivitis and periodontitis). The results of this review should be useful to guide clinical decision-making and further research in the field.