Probiotic supplementation in dental caries: is it possible to replace conventional treatment?

Non-Cariogenic Effect of Milk and Dairy Products on Oral Health in Children and Adolescents: A Scoping Review

Diet plays an important role in the etiopathology of dental caries. Milk and dairy products (DPs), especially in children and adolescents, are important sources of protein, calcium and phosphorus and could have an effect on dental and oral health. The aim of this scoping review was to analyze the scientific literature on the non-cariogenic effect of milk and DPs, with a focus on their potential to prevent dental caries in children and adolescents. PubMed, EMBASE, and Web of Science were searched for publications relevant to our topic from January 2013 to 30 September 2023. Thirty-eight studies were included in the qualitative analysis. The included studies highlight the properties of milk and DPs that contribute to enamel remineralization, exhibit antibacterial action, inhibit the growth of cariogenic bacteria, and promote a balanced oral microbiome. With regard to the addition of probiotics (PBs) and fluoride (F) to DPs, the mixed results of the studies analyzed did not allow a clear statement to be made about their non-cariogenic effects. However, several studies show that the addition of PBs can reduce cariogenic bacteria, create a protective barrier against pathogens and support the host's natural defense mechanisms. Further long-term and high-quality studies are needed to understand the impact of milk and its constituents on oral health in order to promote effective caries prevention strategies in children and adolescents.

Evaluation of Probiotic Effects of Lactobacilli on Mutans Streptococci: An In Vitro Study

AIM

The aim of the present study is to evaluate the probiotic effect of Lactobacillus acidophilus and Lactobacillus rhamnosus on clinical isolates of Mutans Streptococci (MS) and antibiotic susceptibility of these strains to commonly used antibiotics in dentistry.

MATERIALS AND METHODS

Plaque samples from permanent first molars were collected and transferred aseptically onto Mitis-Salivarius agar and incubated at 37°C for 24 hours in the presence of 5-10% CO₂. Mutans streptococci colonies were identified biochemically using Hi-Strep identification kit. The inhibitory activity of the clinical strains of MS on Lactobacilli was investigated using agar-overlay interference technique. Positive inhibition was appreciated as a clear zone around the Lactobacilli. Disk diffusion assay was done as described by CLSI M100-S25 for antibiotic susceptibility. The zone of growth inhibition caused by Lactobacilli and antibiotics on MS clinical strains was measured directly using a vernier caliper. Statistical analysis was done using independent t-test.

RESULTS

Mutans streptococci exhibited positive inhibition with both the probiotic strains and L. acidophilus showed more zones of inhibition than L. rhamnosus. Antibiotic susceptibility of clinical strains of MS showed sensitivity to penicillin and vancomycin, however, tetracycline and erythromycin showed very few resistant strains. The highest zone of inhibition was shown by cephalothin followed by penicillin, tetracycline, ciprofloxacin, erythromycin, and vancomycin.

CONCLUSION

L. rhamnosus and L. acidophilus have strong inhibitory effects on clinical strains of MS. Lactobacillus acidophilus showed a higher zone of inhibition. All the clinical strains of MS were sensitive to penicillin and vancomycin. The highest zone of inhibition was shown by cephalothin.

CLINICAL SIGNIFICANCE

Dental caries remains silent epidemic and increasing antibiotic resistance is another major challenge that threatens the world. Newer methods such as whole-bacteria replacement therapy using probiotics for decreasing harmful oral pathogens and reducing the intake of antibiotics must be explored. More researches to promote use of probiotics should be initiated due to its possible preventive and health maintenance benefits providing an end to new cavities and antibiotic resistance.

Identification of Lactobacillus Strains Capable of Fermenting Fructo-Oligosaccharides and Inulin

Novel probiotic strains that can ferment prebiotics are important for functional foods. The utilization of prebiotics is strain specific, so we screened 86 Lactobacillus strains and compared them to Bifidobacterium breve 2141 for the ability to grow and produce SCFA when 1% inulin or fructo-oligosaccharides (FOS) were provided as the carbon source in batch fermentations. When grown anaerobically at 32 °C, ten Lactobacillus strains grew on both prebiotic substrates (OD₆₀₀ ≥ 1.2); while Lactobacillus coryniformis subsp. torquens B4390 grew only in the presence of inulin. When the growth temperature was increased to 37 °C to simulate the human body temperature, four of these strains were no longer able to grow on either prebiotic. Additionally, L. casei strains 4646 and B441, and L. helveticus strains B1842 and B1929 did not require anaerobic conditions for growth on both prebiotics. Short-chain fatty acid analysis was performed on cell-free supernatants. The concentration of lactic acid produced by the ten Lactobacillus strains in the presence of prebiotics ranged from 73-205 mM. L. helveticus B1929 produced the highest concentration of acetic acid ~19 mM, while L. paraplantarum B23115 and L. paracasei ssp. paracasei B4564 produced the highest concentrations of propionic (1.8-4.0 mM) and butyric (0.9 and 1.1 mM) acids from prebiotic fermentation. L. mali B4563, L. paraplantarum B23115 and L. paracasei ssp. paracasei B4564 were identified as butyrate producers for the first time. These strains hold potential as synbiotics with FOS or inulin in the development of functional foods, including infant formula.

Quantification and gene expression of Lactobacillus casei group species associated with dentinal lesions in early childhood caries

Background

Considering that the Lactobacillus casei group is strongly associated with caries progression, the use of lactobacilli as probiotics must be balanced due to their possible involvement in dental caries.

Objective

This study aimed to detect and quantify L. paracasei, L. rhamnosus, and L. casei group species in the active and arrested dentinal lesions of preschoolers. It also aimed to determine the expression profiles of lactobacilli genes related to adhesion, extracellular polymeric substance regulation, and pyruvate oxidation.

Methods

Total ribonucleic acid (RNA) was extracted from dentinal lesion samples (25 active, 13 arrested) of children between 2 and 5 years of age. The samples were converted to complementary deoxyribonucleic acid (cDNA), and quantitative polymerase chain reaction (qPCR) analyses were performed to quantify and determine the relative abundance (measured by percentage of total bacteria) of L. paracasei, L. rhamnosus, and L. casei group species. The expression profiles of L. paracasei/casei genes (spaC and spxB) and L. rhamnosus genes (spaE and wzb) were assessed. The Student t-test and the Mann-Whitney U test were used for comparisons.

Results

The L. casei group species were found to be part of the viable microbial community in dentinal caries. L. paracasei (p = 0.001), L. rhamnosus (p = 0.022), and L. casei (p = 0.004) group species were abundant in the active dentinal lesions compared to the arrested dentinal lesions. Only the wzb gene (p = 0.006) exhibited a statistically significant difference between the active and arrested lesions in terms of its expression profile; it was expressed to a higher extent in the active dentinal lesions.

Conclusions

The L. casei group species presented in large numbers in the active dentinal caries lesions, indicating that these microorganisms are related to caries activity, and the wzb gene may play an important role in caries progression.

Efficacy of Probiotic Milk for Caries Regression in Preschool Children: A Multicenter Randomized Controlled Trial

This multicenter double-blind randomized controlled trial aimed to determine the efficacy of daily or triweekly consumption of reconstituted milk powder, containing <i>Lactobacillus paracasei</i>SD1, in preschool children for caries prevention. A 6-month intervention was conducted in 487 children (aged 37.6 ± 9.2 months) with ≤4 decayed teeth from 8 childcare centers. Using stratified block randomization, participants were randomly allocated into 3 groups, comprising: (1) daily probiotic, receiving probiotic milk once daily, (2) triweekly probiotic, randomly receiving probiotic milk 3 days a week and the placebo milk for the remaining 4 days, and (3) placebo, receiving milk without probiotics. Each tooth surface was assessed for caries status using the modified Nyvad criteria at baseline (T0), 6 (T6) and 12 (T12) months after T0. Study outcomes were caries transition, including caries progression and regression during the T0–T6, T6–T12 and T0–T12 periods. Negative binomial regression with a generalized linear model was used to estimate the caries outcomes, which were reported as incidence rate ratios (IRRs) and 95% confidence intervals (CIs). At baseline, caries prevalence and mean decayed surfaces were 81.9% and 7.29 ± 7.60, respectively. Three groups were balanced at baseline with an overall dropout rate of 25.2%. After adjusting for age, sex, and the number of noncavitated and cavitated caries at baseline, a decreased caries risk during T0–T6 was shown in both the daily and triweekly probiotic groups (adjusted IRR 0.83, 95% CI 0.72–0.96 in both groups) and during T0–T12 (adjusted IRR 0.84, 95% CI 0.76–0.94, and adjusted IRR 0.86, 95% CI 0.76–0.96, respectively) compared to the placebo group. In contrast, significantly increased regressive surfaces were demonstrated during T0–T6 by adjusted IRR 1.76 (95% CI 1.25–2.48) and 2.01 (95% CI 1.42–2.85) and during T0–T12 by adjusted IRR 1.98 (95% CI 1.50–2.61) and 1.92 (95% CI 1.45–2.55) for the daily and triweekly groups, respectively. In conclusion, probiotic milk consumption either daily or triweekly can modestly prevent new caries, but considerably reverse carious lesions, suggesting that a daily or triweekly dose interval is sufficient to reverse carious lesions.

Reduction of Streptococcus mutans by probiotic milk: a multicenter randomized controlled trial

OBJECTIVE

To investigate the effects of probiotics, Lactobacillus paracasei SD1, on the quantities of Streptococcus mutans in saliva and plaque samples of preschool children.

DESIGN

This randomized trial recruited 487 preschool children from eight childcare centers. Participants were assigned to receive a 6-month course of placebo milk daily (group I), probiotic milk either daily (group II) or three days a week (triweekly, group III). The absolute quantities of S. mutans and total lactobacilli in the saliva and plaque samples at baseline (T0), after intervention (T6), and 6 months after discontinuation (T12) were assessed by qPCR.

RESULTS

Of 487 children, 354 completed all follow-up periods. However, only 268 children (3.2 ± 0.8 years old; groups I = 86, II = 89, and III = 93) provided adequate saliva for qPCR. Whereas the quantities of S. mutans were significantly decreased in groups II and III compared to group I in the saliva and plaque samples at T6 and T12, those of total lactobacilli were significantly increased (p < 0.0167). There was no difference in the quantities of S. mutans or total lactobacilli between groups II and III at any period. Significant changes in the quantities of S. mutans and total lactobacilli lasted until T12 compared to T0 (p < 0.0167).

CONCLUSIONS

Probiotic administration daily or triweekly reduces S. mutans quantities, whereas it increases total lactobacilli quantities that persists at least 6 months after discontinuation in the saliva and plaque samples of preschool children.

CLINICAL RELEVANCE

Daily or triweekly consumption of L. paracasei SD1 supplemented in milk may help prevent dental caries in preschool children.

Probiotics for inflammatory bowel diseases: a promising adjuvant treatment

Inflammatory bowel diseases (IBD) encompass ulcerative colitis (UC), Crohn's disease (CD) and indeterminate colitis (IC), characterising chronic inflammation in the gastrointestinal tract, associated with changes in the immune system and in the intestinal microbiota. Thus, probiotics may offer an alternative or adjuvant approach to conventional therapy. The present review aims to summarise the mechanisms of action of probiotics in IBD and their therapeutic effects. Most of the studies suggest that probiotics are effective in the treatment of UC, especially when several strains are concomitantly administered. Species of Lactobacillus and Bifidobacterium genres are the most commonly used, and some studies even indicate that it is possible to replace medical therapy with probiotic supplementation. Regarding CD, the results of clinical trials are controversial and do not support the use of probiotics in this disease. In conclusion, probiotic supplementation is a promising adjuvant treatment in UC, but not in CD.