TABLE 1.

Summary of probiotic effects from in vitro studies

Author	Type of study	Oral biofilm model	Type of prebiotic/probiotic	Groups (n)	Test method	Probiotics effects
						Species composition	Antimicrobial activity	Immunology
2005
Kõll‐Klais et al26	Screening of oral lactobacilli in chronic periodontitis and healthy patients and antimicrobial activity against Porphyromonas gingivalis, Prevotella intermedia, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans	P. gingivalis, P. intermedia, S. mutans, and A. actinomycetemcomitans grow in suspension	Several lactobacilli strains	Two groups: healthy (n = 15) and chronic periodontitis (n = 20)	Collection of saliva and subgingival samples, plated onto Man–Rogosa–Sharpe agar plates and incubated for 72 h at 37°C and 10% carbon dioxide. The isolated lactobacilli colonies were further analyzed by 16S ribosomal ribonucleic acid (RNA) gene sequencing	Lactobacillus gasseri and Lactobacillus fermentum were most prevalent lactobacilli identified in healthy patients, whereas Lactobacillus plantarum was the most prevalent strain in periodontal disease patients. Healthy patients exhibited higher counts of homofermentative strains than periodontitis patients did	The majority of probiotic strains significantly suppressed P. gingivalis, P. intermedia, S. mutans, and A. actinomycetemcomitans growth	—
2010
Zhu et al29	Screening of bacteria isolated from yogurt for antimicrobial activity against pathogens	P. gingivalis, Fusobacterium nucleatum, A. actinomycetemcomitans, P. intermedia, Prevotella nigrescens, Peptostreptococcus anaerobius, Porphyromonas circumdentaria, Bacteroides fragilis, and Streptococcus sanguinis grown on agar plates	Aliquots of yogurt containing Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, and Bifidobacterium strains	—	Antimicrobial effects based on inhibition zone diameter (in millimeters) on agar plates	—	Aliquots of fresh yogurt significantly inhibited all the periodontal pathogens, whereas heat‐treated yogurt inhibited all the periodontal pathogens except F. nucleatum and P. gingivalis Fresh yogurt but not heat‐treated yogurt also inhibited the commensal bacteria S. sanguinis Probiotic antimicrobial activity varied depending on the sequence of inoculation (probiotics inoculated first, co‐inoculated, or last)	—
2012
Zhao et al 53	Evaluation of the effect of L. acidophilus on secretion of interleukins by gingival epithelial cells exposed to P. gingivalis	Gingival epithelial cells + P. gingivalis	L. acidophilus	Four groups: control (gingival cells); gingival cells + P. gingivalis; gingival cells + L. acidophilus; gingival cells + P. gingivalis + L. acidophilus	RNA and protein levels for interleukin (IL)‐1β, IL‐6, and IL‐8 at 2, 6, and 24 h after bacterial inoculation measured by reverse transcription polymerase chain reaction (PCR) and enzyme‐linked immunosorbent assay	—	—	Probiotic significantly decreased IL‐1β, IL‐6, and IL‐8 levels in a dose‐dependent manner at all time points
Bosch et al85	Screening of acid lactic bacterial strains from healthy children (up to 10 y old) for probiotic candidates	P. gingivalis, F. nucleatum, Treponema denticola, Prevotella denticola and S. mutans grown on agar plates and tested for response to probiotics	Lactic acid bacteria	—	Antimicrobial effects based on inhibition zone diameter (in millimeters) on agar plates	—	From 46 lactic acid bacteria initially screened, 32 inhibited P. denticola, 29 inhibited S. mutans, 24 inhibited F. nucleatum, 24 inhibited T. denticola, and only seven inhibited P. gingivalis From 46 lactic acid bacteria, none were able to inhibit all five pathogenic strains, and 11 strains were able to inhibit four out of the five pathogenic strains	—
Chen et al86	Inhibition of periodontal pathogens by both L. fermentum and Lactobacillus salivarius and by their conditioned broth	S. mutans, S. sanguinis, and P. gingivalis grown on agar plates	L. fermentum and L. salivarius	—	Antimicrobial effects based on inhibition zone diameter (in millimeters) on agar plates and the broth was evaluated by counting the number of bacterial colonies on agar plates after broth treatment	—	Both bacterial strains and their broth exhibited significant inhibition of periodontal pathogens; however, the broth presented a lower inhibition effect than the bacterial strains did	—
2013
Saha et al87	Development and characterization of carboxymethyl cellulose oral thin films for probiotic delivery	—	L. fermentum	—	—	—	L. fermentum remained viable in the oral thin film for 142 d and its antioxidant activity was maintained for 150 d, peaking at 48 h	—
2015
Terai et al26	Screening of acid‐producing bacterial strains isolated from healthy patients for probiotic candidates	P. gingivalis, P. intermedia, A. actinomycetemcomitans, S. mutans, and Streptococcus sobrinus grown on agar plates	14 lactobacilli and 36 streptococci strains isolated from 32 healthy patients	—	16S ribosomal DNA sequencing was used for bacterial identification; antimicrobial effects based on inhibition zone diameter (in millimeters) on agar plates; cariogenic potential was measured by demineralization of bovine tooth enamel; experimental endocarditis infection was assessed in rats by in vivo heart infection with the pathogenic bacteria	—	Isolated Lactobacillus crispatus YIT 12319, L. fermentum YIT 12320, L. gasseri YIT 12321, and Streptococcus mitis YIT 12322 showed no cariogenic potential	Isolated L. crispatus YIT 12319, L. fermentum YIT 12320, L. gasseri YIT 12321, and S. mitis YIT 12322 showed low endocarditis potential
2016
Amižic et al88	Screening of probiotic toothpaste and mouthrinse for antimicrobial effects	Candida albicans, C tropicalis, E faecalis, S. salivarius, and S aureus grown on agar plates	L paracasei or L acidophillus	12 groups: saline; control toothpaste (no probiotic); L paracasei toothpaste; L acidophilus toothpaste; mouthrinse 1; mouthrinse 2; and the combinations of the three toothpastes with the two mouthrinses	Antimicrobial effects based on inhibition zone diameter (in millimeters) on agar plates	—	Probiotic toothpaste significantly inhibited C. albicans and S. salivarius compared to the toothpaste without probiotics and all the mouthrinses With some exceptions, the combinations of probiotic toothpaste and mouth rinses were not significantly different from probiotic toothpaste alone	‐
2018
Slomka et al47	Screening of prebiotic substrates to modulate pathogens/beneficial bacteria in oral biofilm	Multispecies biofilm containing A. actinomycetemcomitans, F. nucleatum, P. gingivalis, P. intermedia, S. mutans, S. sobrinus as representative pathogens and Actinomyces naeslundii, Streptococcus gordonii, Actinomyces viscosus, S. mitis, Streptococcus oralis, S. salivarius, S. sanguinis, and Veillonella parvula as beneficial bacterial species	β‐Methyl‐d‐galactoside; N‐acetyl‐d‐mannosamine; l‐aspartic acid; succinic acid; lactitol, turanose, methionine‐proline, phenylalanine‐glutamic acid	—	Quantitative PCR used to measure bacterial levels at 3, 5, and 10 d	—	N‐Acetyl‐d‐mannosamine, succinic acid, and methionine‐proline prebiotics reduced pathogenic bacteria to <5% in the biofilm; N‐acetyl‐d‐mannosamine resulted in a dose‐dependent increase in the beneficial bacteria, reducing the pathogenic bacteria to 3% at the highest concentrations	—
Yamada et al89	Effect of probiotic metabolite on P. gingivalis infection	P. gingivalis infection of gingival epithelial cells (Epi‐4); P. gingivalis inoculation in mouse model	Metabolite generated by probiotic bacteria (10‐hydroxy‐cis‐12‐octadecenoic acid [HYA])	Four groups: control, P. gingivalis, HYA, P. gingivalis + HYA	Barrier disruption was measured by quantification of desmosomes visualized by transmission electron microscopy	—	HYA significantly inhibited gingival epithelial barrier disruption induced by P. gingivalis	HYA significantly suppressed P. gingivalis E‐cadherin degradation and proinflammatory cytokines IL‐1β, tmor necrosis factor‐α, and IL‐6 in mouse gingival tissue
Zupancic et al 23	Probiotic incorporation into chitosan‐poly(ethylene‐oxide) nanofibers	A. actinomycetemcomitans grown on agar plates	Bacillus sp isolated from a healthy patient	Two groups: A. actinomycetemcomitans; A. actinomycetemcomitans + nanofibers	Antimicrobial effects based on inhibition zone diameter (in millimeters) on agar plates	—	Probiotic significantly inhibited pathogen growth	—
2019
Cornacchione et al30	Identifying the different strains of L. delbrueckii, that inhibit and do not inhibit the growth of P. gingivalis	P. gingivalis grown on agar plates	L. delbrueckii isolated from commercial yogurt products	—	Inhibitory effects based on the inhibitory zone diameter (in millimeters) on agar plates	—	The STYM1 strain of L. delbrueckii inhibited the growth of P. gingivalis by producing inhibitory amounts of hydrogen peroxide	—