Allocation concealment and intervention
SIDE EFFECT, PLAQUE
Patients were instructed about an effective self-performed plaque control, including information about brushing and interproximal cleaning with flossing. Before the study began, the selected individuals were identified by a numeric code. According to a random numeric table generated by a computer software, the study coordinator (F.A.C.F.) allocated each patient into one of the following groups: control (placebo; 30 patients) or test (probiotic therapy; 30 patients).At day 0 (baseline), all patients received supragingival scaling and polishing. Supragingival scaling was performed using both hand instruments (Gracey curettes; Hu-Friedy, Chicago, IL, USA) and ultrasonic device. Supragingival prophylaxis was performed using rubber cup and prophylaxis paste. These procedures were performed by one trained periodontist (G.A.S.) who was not informed about the treatment allocation. The participants received lozenges containing probiotic (test group) or placebo (control group). In the test group, the lozenges contained 10A compounding pharmacy produced the probiotic and non-probiotic lozenges in the same format and they were packed in identical vials. The lozenges were then sent to the coordinator of the study (F.A.C.F.), who marked the code number of each participant on a set of 112 lozenges (amount to be consumed by each participant during 8 weeks), according to the experimental group assigned. The coded lozenges were given to the examiner (M.C.R.), who distributed them to the patients and did not have any access to information regarding the content of the lozenges. In addition, the patients were blinded to the content of the lozenges and the treatment assignment during the study. The study coordinator (F.A.C.F.) revealed the meaning of each code number only when the statistical analysis of the experimental data was completed.The participants received fourteen lozenges (placebo or probiotic) per week. Once a week, they brought back the packs of lozenges that were consumed during the week and then they received new lozenges, sufficient for another week of consumption. At these visits, patients responded to a questionnaire about side effect perceptions during the consumption of lozenges. One research assistant (P.H.F.S) conducted these procedures and was also responsible for monitoring patients’ compliance in the consumption of lozenges.Periodontal clinical parameters were evaluated at baseline and after 2 and 8 weeks using a manual periodontal probe (PCPUNC156; Hu-Friedy, Chicago, IL, USA). At baseline, as well at 8 weeks, gingival crevicular fluid (GCF) samples were collected from 8 non-contigous interproximal sites of each patient. These procedures were conducted by a single trained and calibrated examiner (Y.L.A.S.L.), who was blinded to the experimental groups of the study.