Lactobacillus plantarum is a probiotic bacterium increasingly studied for its potential benefits in supporting oral health, including the management of gingivitis. Scientific evidence suggests that L. plantarum may help reduce the symptoms and progression of gingivitis, though the body of evidence is still emerging and not yet robust enough for a higher evidence rating.

Several randomized controlled trials (RCTs) and in vitro studies have investigated the effects of L. plantarum on oral pathogens and gum inflammation. For example, a 2021 clinical trial published in Journal of Periodontal Research found that oral administration of L. plantarum resulted in a statistically significant reduction in gingival bleeding and plaque indices compared to placebo, suggesting an improvement in gingival health. Laboratory studies have demonstrated that L. plantarum can inhibit the growth and adhesion of key periodontopathogens such as Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, both implicated in gingivitis and periodontitis.

The proposed mechanisms include competitive exclusion of pathogenic bacteria, modulation of the host immune response, and production of bacteriocins that directly suppress oral pathogens. While promising, these findings are based on a limited number of clinical studies with relatively small sample sizes, and longer-term, larger-scale trials are needed for definitive conclusions.

In summary, there is a moderate level of scientific validation for the use of L. plantarum in supporting gingivitis, warranting further investigation but offering a rationale for its use as an adjunct in oral care.