The Effect of a Streptococcus Probiotic in Periodontal Therapy: a Randomized Controlled Trial

Materials and methods This double-blind, placebo-controlled, randomized (1:1 ratio) controlled trial with two parallel arms involved 48 patients with advanced adult periodontitis. They were recruited at the periodontology department of the Cukurova university, Turkey. All patients referred for periodontal treatment were screened for eligibility.The project was approved by the ethical committee for clinical trials of the Cukurova University in Turkey with number . No changes in the trial design were made after approval by the Ethical Committee.

Sample size calculation and randomization Power analysis prior to the start of the study was difficult since no previous randomized controlled trials on this study product were available. The sample size was determined. Pocket probing depth was taken into account, with an expected difference of 0.82mm and a standard deviation of 0.61mm. It was calculated that 10 patients were needed in each group to provide 80% power with an alpha of 0.05 . Despite this low number and taking into consideration studies comparing the adjunctive effect of antibiotics to scaling and rootplaning, it was decided to include 24 patients in each group.

Randomization of the patients was done by block randomization . The study coordinator distributed the coded bottles to the examiner at baseline, 4 weeks and 8 weeks visit. Except for the study coordinator, all patients and study personnel were blinded to the study group allocation. Before sending the data to the biostatistician, the code was broken to group the patients to the proper groups.

Treatment protocol Patients fulfilling the eligibility criteria were asked to participate in the study and after approval to sign an informed consent. Baseline examination included full-mouth probing pocket depth , gingival recession and bleeding on probing measured at six sites per tooth. Additionally the plaque en gingival indexes were noted. The full-mouth plaque index was recorded.After baseline periodontal examination and microbial analysis, an oral hygiene instruction was given (toothbrush, interdental brush). Initial periodontal therapy consisted of a full-mouth one-stage disinfection approach . All clinical procedures were performed by the same periodontist . The patient was asked to rinse for 2 minutes with a 0.12% chlorhexidine solution without alcohol . Scaling and rootplaning were performed on 2 consecutive days using an ultrasonic scaler under 0.12% chlorhexidine irrigation and with hand instruments. All mucosal surfaces were afterwards disinfected and the tongue was brushed for 1 minute. Besides, the participants were randomized over the 2 treatment groups: control or probiotic group.The participants of the probiotic group were asked to let a probiotic tablet dissolve on their tongue 2 times a day for 3 months. The participants in the control group were asked to do the same with a placebo tablet. All patients were instructed to use the tablets after brushing their teeth in the morning and in the evening. The probiotic and placebo tablets were identical in shape, texture, taste and composition except that Streptococcus were added for the probiotic tablet. All patients were supplied with the same toothpaste . It was asked not to use any probiotic containing products during the course of the study. Neither was it allowed to use drugs with anti-inflammatory properties, chlorhexidine or other mouthrinses during the study.

At designated time points, follow-up visits were planned. 30 days and 60 days after initiation of the therapy clinical evaluation and microbial analysis were performed. 90 days and 180 days after the initial treatment all baseline parameters were recorded .