What do systematic reviews say?

Lactobacillus-derived postbiotics vs Not specified

No meta-analysis was conducted; the narrative synthesis reported inhibition of Streptococcus mutans growth and biofilm formation.

• Postbiotics and Dental Caries: A Systematic Review. 2025 All outcomes

  24 h to 7 days · laboratory setting
  no estimate extracted
  12 studies
  GRADE not reported

Lactobacillus-derived postbiotics vs Not specified

No meta-analysis was conducted; the narrative synthesis reported reduced expression of Streptococcus mutans virulence genes.

• Postbiotics and Dental Caries: A Systematic Review. 2025 All outcomes

  24 h to 7 days · laboratory setting
  no estimate extracted
  7 studies
  GRADE not reported

Probiotic mouthwash (e.g., Lactobacillus-based) vs Blank control

Probiotic mouthwash has inconsistent effects on Mutans streptococci colony counts versus blank control; the evidence is very uncertain (very low certainty).

• The efficacy of mouthwashes on oral microorganisms and gingivitis in patients undergoing orthodontic treatment:… 2023 All outcomes

  <=3 months (short-term) · Orthodontic patients undergoing orthodontic treatment (randomized controlled trials; multiple countries)
  Colony count of MS was significantly reduced compared to blank control [53]. Colony count of MS was insignificantly increased compared to baseline [33].
  2 studies
  Very low

Significant salivary microbial (Lactobacillus) load vs No/low significant microbial load

A significant salivary microbial (Lactobacillus) load was associated with higher odds of dental caries (OR 3.82, 95% CI 3.439-4.192; ungraded).

• Prevalence of dental caries and associated factors among primary school children in Ethiopia: systematic review and… 2024 All outcomes

  Schools; Ethiopia (Addis Ababa, Bahir Dar, Finote Selam, Harer, Debre Birhan, North Showa)
  OR 3.82 [3.439, 4.192]
  Studies not reported
  GRADE not reported

Postbiotics from Lactobacillus spp. (cell-free supernatants, biosurfactants, lipoteichoic acid, bacterial lysates) vs No prior SDF application (untreated dentin control)

Postbiotics reduce expression of S. mutans biofilm/virulence genes (gtfB, gtfC, ftf) in vitro (ungraded narrative synthesis).

• Postbiotics and Dental Caries: A Systematic Review. 2025 All outcomes

  Exposure 24 h to 7 days · Laboratory (in vitro)
  Postbiotics downregulated expression of S. mutans virulence and exopolysaccharide-synthesis genes (e.g., gtfB, gtfC, gtfD, ftf) in 10 in vitro studies; no pooled estimate.
  8 studies
  GRADE not reported

Postbiotics from Lactobacillus spp. (cell-free supernatants, biosurfactants, lipoteichoic acid, bacterial lysates) vs No prior SDF application (untreated dentin control)

Postbiotics inhibit S. mutans adhesion to tooth surfaces in vitro (ungraded narrative synthesis).

• Postbiotics and Dental Caries: A Systematic Review. 2025 All outcomes

  Exposure 24 h to 7 days · Laboratory (in vitro)
  Postbiotics (mainly biosurfactants and lipoteichoic acid) interfered with S. mutans adhesion to tooth/hydroxyapatite surfaces in 5 in vitro studies; no pooled estimate.
  5 studies
  GRADE not reported

Postbiotics from Lactobacillus spp. (cell-free supernatants, biosurfactants, lipoteichoic acid, bacterial lysates) vs No prior SDF application (untreated dentin control)

A single in vitro study found postbiotics reduce enamel demineralization (ungraded).

• Postbiotics and Dental Caries: A Systematic Review. 2025 All outcomes

  Exposure 24 h to 7 days · Laboratory (in vitro)
  One in vitro multispecies-biofilm study reported that a postbiotic (L. reuteri cell-free supernatant) reduced enamel demineralization, indicating a protective effect against caries; no pooled estimate.
  1 study
  GRADE not reported

Non-syndromic cleft lip and palate (CLP) status and its oral microbiota (exposure/grouping) vs Children and adolescents aged 0-18 years without CLP (controls)

A meta-analysis found no significant difference in mean Lactobacillus spp. levels between children with and without CLP, with high heterogeneity; the evidence is ungraded.

• Characterization of the oral microbiota and the relationship of the oral microbiota with the dental and periodontal… 2024 All outcomes

  Multiple countries; pediatric cleft/craniofacial care; saliva, dental plaque, subgingival plaque and nasal/oropharyngeal samples
  For the outcome of the presence of Lactobacillus spp., there were no significant differences between patients with CLP and healthy patients, and the diversity of the studies led to high heterogeneity; however, the p…
  Studies not reported
  GRADE not reported

Intervention not reported

• Clinical Effects of Sugar Substitutes on Cariogenic Bacteria: A Systematic Review and Meta-Analysis. 2024 All outcomes

  Single study (Ly et al. 2008), xylitol or maltitol, not pooled
  Narrative (no effect size) No significant change in Lactobacillus spp. after xylitol or maltitol consumption
  1 study
  GRADE not reported

Cleft lip and/or palate (CL/P) vs No cleft lip and/or palate (non-CL/P)

No significant difference in Lactobacillus spp. presence was reported; GRADE was not reported.

• Characterization of the oral microbiota and the relationship of the oral microbiota with the dental and periodontal… 2024 All outcomes
  MD 1.40 [1.33, 1.47]
  2 studies · 152 participants
  GRADE not reported

Probiotics vs placebo or control

Probiotics may make little to no difference to Lactobacillus count versus control (MD -0.78 CFU/mL, 95%CI -1.65 to 0.09; very low certainty).

• Efficacy of Probiotic Consumption on Oral Outcomes in Children and/or Adolescents: A Meta-Analysis. 2024 All outcomes

  follow-up: mean 5.2 months · Healthy children and/or adolescents (<18 years) without systemic disease; RCTs from multiple countries (India, Thailand, Spain, Australia, New Zealand, Sweden, Poland, Colombia, Saudi Arabia); mostly school/community and clinic settings · Overall (all presentations pooled)
  MD -0.78 [-1.65, 0.09]
  6 studies · 1143 participants
  Very low

Intervention not reported

• Characterization of the oral microbiota and the relationship of the oral microbiota with the dental and periodontal… 2024 All outcomes

  Narrative synthesis: significantly higher in CLP vs controls (Ahluwalia, Lucas, Hassani, Cheng, Sundell)
  no estimate extracted
  5 studies
  GRADE not reported

Placebo rinse vs Pre-treatment (baseline, same group)

Placebo rinse did not significantly change Lactobacillus counts relative to baseline; not GRADE-rated.

• The antiplaque/anticariogenic efficacy of Salvadora persica (Miswak) mouthrinse in comparison to that of… 2019 All outcomes

  Pre- vs post-treatment · In vivo clinical trial (human oral cavity)
  MD 0.34 [-0.50, 1.18]
  2 studies · 30 participants
  GRADE not reported

Salvadora persica (miswak) mouthrinse vs Pre-treatment (baseline, same group)

Salvadora persica rinse reduced Lactobacillus counts relative to baseline; not GRADE-rated.

• The antiplaque/anticariogenic efficacy of Salvadora persica (Miswak) mouthrinse in comparison to that of… 2019 All outcomes

  Pre- vs post-treatment · In vivo clinical trial (human oral cavity)
  MD 1.54 [0.91, 2.17]
  2 studies · 30 participants
  GRADE not reported

Salvadora persica (miswak) mouthrinse vs Placebo rinse

Salvadora persica rinse reduced Lactobacillus counts more than placebo (favours Salvadora persica); not GRADE-rated.

• The antiplaque/anticariogenic efficacy of Salvadora persica (Miswak) mouthrinse in comparison to that of… 2019 All outcomes

  Post-treatment · In vivo clinical trial (human oral cavity)
  MD -1.12 [-1.45, -0.79]
  2 studies · 60 participants
  GRADE not reported