Effects of different periodontal treatments in changing the prevalence and levels of Archaea present in the subgingival biofilm of subjects with periodontitis: A secondary analysis from a randomized controlled clinical trial.

OBJECTIVE: 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 mean level of Archaea. METHODS: Fifty-nine (59) subjects were randomly assigned to receive scaling and root planing (SRP) alone or combined with metronidazole (MTZ; 400 mg/TID) or either with MTZ and amoxicillin (AMX; 500 mg/TID) for 14 days. Clinical and microbiological examinations were performed at baseline and at 6 months post-SRP. Six subgingival plaque samples per subject were analysed for the presence and levels of Archaea using quantitative polymerase chain reaction. RESULTS: Scaling and root planing alone or combined with MTZ or MTZ + AMX significantly reduced the prevalence of subjects colonized by Archaea at 6 months post-therapy, without significant differences among groups (P > .05). Both therapies led to a statistically significant decrease in the mean percentage of sites colonized by Archaea (P < .05). The MTZ and MTZ + AMX group had a significantly lower mean number of sites colonized by Archaea and lower levels of these micro-organisms at sites with probing depth ≥5 mm at 6 months compared with SRP group (P < .05). CONCLUSION: Periodontal treatments including adjunctive MTZ or MTZ + AMX are more effective than mechanical treatment alone in reducing the levels and prevalence of sites colonized by Archaea in subjects with chronic periodontitis.

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 (r(2) = -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.