Probiotics for maintaining oral health during fixed orthodontic treatment: A systematic review and meta-analysis

IntroductionTo systematically review the effect of probiotics on oral health during treatment with fixed orthodontic appliances.MethodsPubMed, Embase and the Cochrane Library were searched up to August 2022 using broad MeSH terms and keywords. Randomized clinical trials comparing a probiotic with a control/no treatment; at least 10 patients/group undergoing fixed orthodontic therapy; and reporting at least one oral health-related parameter were included.ResultsThe most reported parameters in the 14 included studies were the microbiological counts of mutans streptococci and lactobacilli, microorganisms associated with white spot lesions (WSL). A meta-analysis of these showed a positive effect of probiotics on mutans streptococci. Probiotic treatment led to significantly less patients with high counts and significantly more with low counts of these bacteria. An effect on the lactobacilli counts was not seen. However, the sole clinical study investigating WSL could not demonstrate a clinical effect of probiotics on these lesions. Additionally, one study reported encouraging results of probiotics on bad breath and one on the occurrence of traumatic oral lesions. One study found reduced counts of Porphyromonas gingivalis in the probiotic group. The clinical results of probiotics on plaque index were ambiguous: one study reported that probiotics reduce the plaque and gingival index, and two that probiotics had no significant influence on plaque index.ConclusionProbiotics are a promising option to lower mutans streptococci counts in patients undergoing fixed orthodontic therapy. However, due to the heterogeneity of the studies, it is not possible to draw conclusions about one specific probiotic.