Background: To examine the adjunctive effect of a Lactobacillus reuteri probiotic (ATCC PTA 5289 & DSM 17938) on the re-instrumentation of residual pockets.

Methods: This randomized, double-blind, placebo-controlled study included 39 previously non-surgically treated periodontitis patients. A re-instrumentation was carried out, and probiotic and/or placebo drops were applied according to the study protocoll. Patients afterwards received lozenges to use 2×/day for 12 weeks. Probing pocket depth (PPD), recession, bleeding on probing and plaque levels were analysed, next to the microbiological impact.

Results: No effects of the probiotic drops could be found. However, after 24 weeks, the overall PPD in the probiotic lozenges group (2.64 ± 0.33 mm) was significantly lower compared to the control lozenges (2.92 ± 0.42 mm). This difference was even more pronounced in moderate (4-6 mm) and deep (≥7 mm) pockets. In the probiotic lozenges group, there were also significantly more pockets converting from ≥4 mm at baseline to ≤3 mm at 24 weeks (67 ± 18% versus 54 ± 17%) and less sites in need for surgery (4 ± 4% versus 8 ± 6%). However, the probiotic products did not influence the microbiological counts of the periodontopathogens.

Conclusion: The adjunctive consumption of L. reuteri lozenges after re-instrumentation improved the PPD reduction, without an impact on pocket colonization with periodontopathogens.