eibacillus rhamnosus and Limosilactobacillus reuteri are the most frequently investigated species in dentistry. Probiotics have both preventive and therapeutic effects and the mechanisms of action involve local (direct) as well as systemic (indirect) events. 8 The local effects in the dental biofilm include co-aggregation, release of antibacterial substances and competitive exclusion of pathogens. In particular, L. reuteri has a unique capac-ity to produce growth-inhibiting reuterin, hydrogen peroxide and ammonia. The gut-mediated systemic effects rely on stimulation and modulation of the mucosal immune system with increased output of immunoglobulins, cytokines and host-defense peptides (e.g. beta-defensin 2) in saliva and gingival crevicular fluid. 8 Probiotics are available in selected dairy products and fermented food suitable for school-based interven-tions for children. In clinical dentistry, tablets/lozenges containing one or more probiotic lactobacilli strains are most practical. Commonly, products have around 1 billion live bacteria per tablet and the recommended daily intake is 1-2 tablets daily. Probiotics are “generally recognized as safe” (GRAS) by the FDA and adverse effects following intake are very rare. No serious side effects are reported from studies conducted within dentistry. However, for critically ill and immune-compromised cases, or when in doubt, it is recom-mended to consult the patient’s physician. Table 1. Summary of probiotic effects when applied during orthodontic treatment Microbiota Salivary pH Plaque amount Gingivitis Significant reductions of oral pathogens 17-19 Probiotic rinses increase alkalinity 20 Probiotics as effective as chlorhexidine rinses 21-22 Gingival index significantly reduced 21-22 Reduced by almost 50% in patients with fixed orthodontics 23 Traumatic oral lesions Oral malodor Halitosis significantly reduced 24 No difference compared with placebo 25 Prevention of white spot lesions Probiotics in General Dentistry In gastro-intestinal and pediatric medicine, there is evidence to use probiotics against acute gastroenteritis, irritable bowel disease, antibiotic-associated diarrhea and infantile colic. 9, 10 In dentistry, the most commonly applied probiotic supplement is the dual strain L. reuteri lozenge (Prodentis) by BioGaia AB, Sweden. A large number of clinical trials have estab-lished beneficial effects on gingivitis and chronic peri-odontitis when given as an adjunct to the conven-tional treatment pillars in periodontal care, scaling and root debridement. In a systematic review based on four trials, the addi-tion of Prodentis reduced gingival bleeding on probing by 15% and the periodontal pocket depth by an average of 0.7 mm. 11 Interestingly, the intervention seems most helpful for the deepest pockets (> 6mm). In a recent trial, seven out of 10 residual pockets were successfully treated after 12 weeks and this reduced the number of sites in need of periodontal surgery by 50%. 12 The bene-ficial effects of probiotics are however not limited to professional care at the clinic. A recent study has shown that the consumption of probiotic L. reuteri-lozenges was an efficacious measure to improve and maintain periodontal health among navy sailors at sea with waning efficacy of their personal oral hygiene. 13 The use of probiotics to manage peri-implant diseases has gained interest since inflammation and occlusal overload are the most common reasons for implant failure. Titanium implants create a specific ecosystem and mechanical debridement cannot completely resolve the clinical inflammation. The adjunctive use of L. reuteri for 30 days can improve the clinical parameters around implants with peri-mucositis and peri-implantitis. 8 Data suggests that the probiotics combat the inflammation by affecting the host response rather than by affecting selected pathogens. Candida albicans are common in humans and around 50% of the healthy population harbor its neutral blastospore form in the oral cavity. Under certain circumstances, such as hyposalivation, polypharmacy and wearing dentures, the homeostatic state is disrupted which results in oral candidiasis. Jørgensen and coworkers 14 showed that probiotics help; L. reuteri co-aggregates with various Candida species and inhibits growth via production of H2O2 and organic acids. Consequently, the use of Prodentis among the frail elderly have significantly reduced sali-vary and biofilm counts of C. albicans and the regimen seems to be particularly suitable for older adults living in nursing homes. 15 Oral Health Maintenance The role of probiotics in oral health maintenance among patients undergoing fixed orthodontic therapy has recently been addressed in a systematic review. 16 The main benefits are summarized in Table 1. 17-25 Several clinical trials have unveiled that probiotic supplements can alter the composition of the oral microbiota in orthodontic patients. One example is the study by Widyarman and coworkers 26 that showed that daily intake of Prodentis lozenges containing two strains of L. reuteri could create an almost total makeover of the biofilm with significant reductions of Streptococcus mutans, Streptococcus sobrinus, Porphyromonas gingivalis and Aggregati-bacter actinomycetemcomitans. Collectively, data from the available research illus-trate that daily intake of probiotic lactobacilli can over-come the microbial perturbation caused by fixed appli-ances and bounce back the dental biofilm towards a more health-associated composition. Fig. 2 pictures a www.orthodontics.com Summer 2021 15
Journal of the American Orthodontic Society Summer 2021: Page 15
