Reduction in prevalence of Archaea after periodontal therapy in subjects with generalized aggressive periodontitis.

Background There is evidence of a possible relationship between Archaea and periodontal disease; however, to date few studies have assessed the changes in prevalence of this domain after periodontal therapy. The aim of this randomized double-blind and placebo-controlled study was to assess if periodontal treatment with or without systemic antibiotic would change the prevalence of Archaea after periodontal therapy. Methods Thirty subjects were randomly assigned to receive scaling and root planing (SRP) alone or combined with metronidazole (MTZ) + amoxicillin (AMX) for 14 days. Clinical and microbiological examinations were performed at baseline and at six months post-SRP. Nine subgingival plaque samples per subject were analysed for the presence of Archaea. Results SRP alone or combined with MTZ + AMX significantly reduced the prevalence of subjects colonized by Archaea at six months post-therapy. However, no significant differences between treatment groups were observed (p > 0.05). Both therapies led to a statistically significant decrease in the mean percentage of sites colonized by Archaea (p < 0.05). A negative Spearman correlation was observed between the presence of Archaea and the mean clinical attachment gain at six months post-therapy (r2 = -0.61; 95% CI -0.80– -0.31; p = 0.003). Conclusions SRP alone or combined with MTZ + AMX provides a similar reduction in the prevalence of Archaea in the subgingival biofilm of subjects with generalized aggressive periodontitis.