Forty-seven patients, 16 in the probiotic group, 16 in the antibiotic group and 15 in the placebo group were analyzed. All participants completed the study period and complied with the study requirements (Fig. 1). Adverse events were observed in one participant from antibiotic group (nausea). The periodontal diagnosis of all participants was Periodontitis Stage III generalized Grade B. Demographic, medical and clinical characteristics are described in Table 1. No significant differences were found between groups at baseline (p > 0.05).
The mean CAL, PPD, BOP and PI values at baseline and at 3, 6, 9, and 12 months follow-up of all groups are presented in Table 1 and Table 2. All treatment groups showed a significant reduction of PPD and PI at all timepoints, inter- group comparison however revealed that there were no significant differences between the treatment modalities (p > 0.05) (Table 1). In terms of CAL, the probiotic group showed a significant reduction at 3- and 9- months follow-up whereas the antibiotic group showed a significant reduction at 3- and 6- months follow-up. The placebo group on the other hand, showed a significant reduction of CAL at all time points (p < 0.0125). With respect to BOP, the antibiotic and placebo groups showed a significant reduction at 3- 6- and 12- months follow up (p < 0.0125) whereas the probiotic group did not exhibit any improvement at any time point (p > 0.05).
The magnitude of statistical changes (Effect size) in all clinical parameters from baseline to 3-, 6-, 9- and 12- month follow-up was similar in all treatment modalities (Table 2). Furthermore, inter-group comparison revealed no significant differences in the changes (∆) of any clinical parameter between the treatment groups (p > 0.05)
Moderate pockets (PPD = 4–6 mm) in the antibiotic group revealed an increase in CAL at 3 months and a significant reduction of PPD at 12 months. Moderate pockets also showed a significant reduction in PPD in the placebo group at 3- and 12- month follow up in placebo group (Table 3. All, p < 0.025).
At 12 months follow-up, 80.3%, 77.8% and 77.2% of the baseline moderate pockets (PPD = 4–6 mm) presented a PPD ≤ 3 mm in the probiotic, antibiotic and placebo group respectively, without significant differences between the groups (p > 0.05) (Table 4). With respect to the baseline deep pockets (PPD > 7 mm), 42.4%, 41.7% and 38.8% of these pockets presented a PPD ≤ 3 mm, and 47%, 50% and 45.9% presented PPD = 4–6 mm, without significant between the treatment groups (p > 0.05) (Table 4). Pocket closure was 78.1%, 76.7% and 74.4% in the in the probiotic, antibiotic and placebo group, without significant differences between the treatment modalities (p > 0.05) (Table 4).
The number of teeth and sites with PPD ≥ 5, ≥6 and ≥ 7 mm were significantly reduced in all groups and without significant difference between the treatment modalities at 12 months follow-up (p > 0.05) (Table 5). While probiotics reduced the percentage of patients with PPD ≥ 5 mm and PPD ≥ 6 mm at 12 months, antibiotics reduced the percentage of patients with PPD ≥ 6 mm and PPD ≥ 7 mm (p < 0.025) (Table 6).
The use of antibiotics significantly increased the number of patients with low risk for disease progression at 12 months, and also significantly reduced the number of patients at higher risk for disease progression (Table 6). In addition, the antibiotic and placebo group showed at 12 months a reduced necessity for additional therapy in ≥ 3 sites but without significant differences between the both groups (Table 6).