Maintaining a Healthy Microbiome
Probiotics For Oral Health
The oral microbiome, a very important component of the human microbiome, contains hundreds to thousands of diverse species that are present in various places, such as on the teeth, gums, cheeks, palate, lips, and tonsils (Arweiler 2016; Dewhirst 2010). Dysbiosis within the oral cavity plays a role in the development of dental cavities, gingivitis, and periodontal disease. A growing body of evidence indicates that restoring healthy populations of beneficial oral bacteria through probiotic therapy can have an important role in preventing and treating these conditions (Gupta 2017; Rosier 2017; Haukioja 2010; Allaker 2017).
Dysbiosis of the oral microbiome is associated with deepening of the periodontal pockets and periodontitis, a chronic inflammatory condition that can damage the soft tissues and bone and, eventually, lead to tooth loss (Gupta 2017; Meuric 2017; Jiao 2014; Deng 2018). Periodontitis also increases the risk of certain systemic diseases including vascular disease, diabetes, and some forms of cancer (Deng 2018). Several studies found that probiotics can reduce gum bleeding and periodontal pocket depth in patients with periodontal disease, and decrease alveolar bone loss in animal models (Allaker 2017; Maekawa 2014; Gatej 2018; Haukioja 2010; Krasse 2006). The benefits of probiotics may be related to their ability to compete with harmful microbes for nutrients, produce molecules that inhibit harmful bacteria, and cause beneficial changes in immune responses (Allaker 2017).
In a randomized controlled trial in patients with periodontal disease, taking a daily capsule containing 10 mg of heat-killed Lactobacillus plantarum L-137 enhanced the effectiveness of scaling and root planing at reducing periodontal pocket depth (Iwasaki 2016). Although the bacteria in this supplement were no longer viable, other studies have shown that the heat-killed form of L. plantarum L-137 has immune-modulating effects (Fujiki 2012), which may have been responsible for its positive impact on periodontal health.
Another promising supplement for periodontal disease is the probiotic strain L. reuteri (Martin-Cabezas 2016; Kumar 2017). Several clinical trials have found that lozenges made with this probiotic species, when added to regular scaling and root planing, reduce plaque formation, gingival bleeding, and pocket depth, and increase the attachment of the gums to the tooth root in patients with chronic periodontal disease (Ince 2015; Teughels 2013; Vivekananda 2010; Szkaradkiewicz 2014; Tekce 2015). In addition, a 2018 randomized controlled trial found that L. reuteri lozenges showed benefits in patients with mucositis and peri-implantitis, two inflammatory conditions that may involve the tissues surrounding a dental implant (Galofre 2018).
The probiotic bacterium L. salivarius WB21 has been found to decrease levels of harmful bacteria in dental plaque (Mayanagi 2009), improve gingival health (Iwamoto 2010), and reduce the risk of periodontal disease (Shimauchi 2008). In other clinical trials, a probiotic mouth rinse containing L. salivarius NK02 improved the effectiveness of scaling and root planing for periodontal disease (Sajedinejad 2017), and a lozenge containing L. rhamnosus GG and Bifidobacterium animalis subspecies lactis BB-12 decreased plaque development and enhanced gum health in healthy subjects (Toiviainen 2015).
Streptococcus salivarius M18 is a probiotic organism that has demonstrated antibacterial effects against S. mutans, an oral bacterium implicated in the formation of dental cavities. It has also been shown to produce enzymes that decrease dental plaque accumulation and acidification (Burton 2013). In a randomized controlled trial, risk factors for cavity development improved after 90 days in children treated with a daily lozenge providing at least 1 billion CFUs of S. salivarius M18 (Di Pierro, Zanvit 2015). In another placebo-controlled trial, three months of treatment with oral S. salivarius M18, at a daily dose of 3.6 billion CFUs, led to greater improvements in plaque scores compared with placebo in children with dental cavities. In addition, bacterial analysis showed that the presence of S. mutans was diminished in children with the highest apparent colonization levels of the probiotic strain (Burton 2013).
Various Lactobacillus species have also been found in laboratory studies to inhibit S. mutans (Lin, Chen 2017; Wasfi 2018). Similar benefits were found in clinical studies. In a randomized controlled trial, probiotic mouth rinses containing either Bacillus coagulans or a mixture of L. acidophilus, B. longum, B. lactis, and B. bifidum, were found to both reduce plaque and improve gum health better than a placebo in children (Yousuf 2017). In another randomized controlled trial, daily use of a chewable tablet with three probiotic Streptococcus species resulted in a lower risk of cavities compared with placebo in healthy two- to three-year-old children (Hedayati-Hajikand 2015).
A broad body of research shows that xylitol, a non-digestible sugar alcohol, has prebiotic effects not only in the gut but also in the mouth (Makinen 2010; Nayak 2014). Xylitol, as a supplement and as an ingredient in toothpastes, mouth rinses, chewing gums, and candies, has been found to reduce levels of cavity-causing bacteria in the saliva and plaque, decrease plaque formation, and inhibit tooth decay (Nayak 2014). A 2017 systematic review and meta-analysis concluded that xylitol is effective for cavity prevention (Janakiram 2017). Another review found that toothpastes with both xylitol and fluoride may protect against cavities more effectively than fluoride-only toothpastes in children (Riley 2015).
For more information about periodontal disease and dental cavities, please see the Oral Health protocol.