Influence of periodontal treatment on blood microbiotas: a clinical trial

Abstract

Objective: To investigate the effects of periodontal treatment on the abundance and diversity of blood microbiota.

Methods and materials: Twenty-seven periodontitis patients were randomly allocated to a control group (A) and two test groups (B1 and B2). Group A patients received full-mouth scaling and root planing (SRP), group B1 patients received subgingival glycine air polishing (GAP) right after SRP, and group B2 patients received subgingival glycine air polishing right before SRP. Peripheral blood samples were obtained at the baseline, the day after periodontal treatment, and 6 weeks after treatment and evaluated using nested polymerase chain reaction and 16SrRNA Gene Sequencing (Miseq platform).

Results: All participants exhibited significant improvements in the clinical parameters evaluated at the 6-week follow-up visit compared to the values at the baseline, but no significant differences were observed between the three groups. The total bacterial count was lowest in group B2. The bacterial species diversity (α-diversity) in group B1 was significantly higher (Chao-1 index, P = 0.03) and Porphyromonas and Pantoea were the dominant genera (linear discriminant analysis (LDA > 2)) in this group the day after treatment compared to the baseline. No significant difference was detected in the relative abundance and α-diversity of blood microbiota between the baseline and 6 weeks after treatment.

Conclusion: Local periodontal treatment merely disrupts the stability of blood microbiota in the short term. Periodontitis treatment using full-mouth SRP followed by adjunctive GAP is a promising approach to reduce the introduction of bacteria into the bloodstream during the procedure.

Keywords: 16SrRNA; Blood microbiota; Glycine air polishing; Periodontitis.

Figure 1. Flow chart representing the characteristics of the study groups and the study design.

FM-SRP: full-mouth scaling and root planing, GAP: glycine air polishing, OHI: oral health instruction.

Figure 2. Description of glycine air polishing (GAP).

(A) Plaque staining before the treatment; (B) Removal of visible plaque using supragingival GAP; (C) Subgingival GAP performed with a plastic nozzle inserted into periodontal pockets.

Figure 3. Agarose gel electrophoresis of representative polymerase chain reaction amplification result with total bacterial 16S rRNA general primers.

M - Marker, NTC - negative control (double distilled water as the DNA template). A - Group A, B - Group B1, C - Group B2, 1 - sample number, a - baseline, b - the day after full-mouth SRP, c - 6 weeks after full-mouth SRP.

Figure 4. Taxonomic differences in the microbial 16S rRNA gene in the blood before treatment (baseline) and 6 weeks post-treatment (6-week visit).

(A) Relative abundance of the four most common bacterial phyla (B) Relative abundance of the 23 most common bacterial genera (C) LEfSe analysis showed the dominant blood bacteria at 6 weeks after full-mouth SRP.

Figure 5. Blood bacterial changes the day after treatment in Group B1.

(A) Indices of alpha-diversity in Group B1; Box plots depicting bacterial diversity according to the Chao-1 index, observed species, PD_whole_tree, and Shannon index. The black line in each column represents the median value. (B) Relative abundance of bacterial genus pre- and post-treatment. (C) The dominant bacteria in the blood the day after full-month SRP.