The Probiotic Effects of Lactobacillus brevis CD2 on Caries Related Variables of Dental Plaque Biofilm

Objectives: This study was based on the research question: "Does L. brevis CD2 have an effect on the acidogenicity of sugar-exposed bacteria? To solve this question, a multistep study was planned: first, an in vitro investigation aimed to assess the acid production of monoculture bacterial solutions; and second, an ex vivo experiment to evaluate the production or inhibition of acids from plaque samples. Methods: L. brevis CD2 and several control strains (Lactobacillus brevis CD2, Lactobacillus reuteri DSM 17938, Lactobacillus rhamnosus LB21, Lactobacillus plantarum 931, Streptococcus mutans Ingbritt) were tested with various sugars; pH changes were recorded at specific time points using a micro-pH electrode. Additionally, for the ex vivo phase, the same sugars were added to equal amounts of pooled plaque from 9 healthy subjects with bacterial suspensions, as well as a control solution, and pH was monitored for up to 90 minutes. For the ex vivo phase, 9 adults were randomised in a crossover design for 28 days. For the in vivo phase, 26 healthy subjects used 1/2 lozenges 3 times daily containing either L. brevis CD2 (active) or no probiotic bacteria (placebo). Plaque acidogenicity was assessed using the microtouch method after a 10 ml mouth rinse containing 10% sucrose for 1 minute (on day 0 and day 28). Results: L. brevis CD2 exhibited the highest ability to inhibit the fermentation of fructose, lactose, and sucrose compared to the control strains (P < .05). A significant reduction in plaque acidogenicity was observed in vivo from day 0 to day 28 in the test group (P < .05). Conclusions: This study indicates that L. brevis CD2 mitgates the acidogenic attributes of plaque biofilm organisma in vitro, in vivo and ex vivo, suggesting its potential benefit as a caries preventive probiotic agent.