Multilevel analysis of bacterial counts from chronic periodontitis after root planing/scaling, surgery, and systemic and local antibiotics: 2-year results

Abstract

Aim: To follow changes (over 2 years) in subgingival bacterial counts of five microbial complexes including health-related Actinomyces spp. in deeper pockets (≥5 mm) after periodontal treatments. Methods: Eight different treatments were studied: (1) scalingroot planing (SRP); (2) periodontal surgery (SURG)systemic amoxicillin (AMOX)systemic metronidazole (MET); (3) SURGlocally delivered tetracycline (TET); (4) SURG; (5) AMOXMETTET; (6) AMOXMET; (7) TET; and (8) SURG AMOXMETTET. Antibiotics were given immediately following SRP. Subgingival plaque was collected mesiobuccally from each tooth, except third molars, from 176 subjects, completing the study, at baseline, 3, 6, 12, 18, and 24 months post-treatment and analysed for 40 different bacteria using checkerboard hybridization. A negative binomial (NB) generalized estimating equation (NB GEE) model was used to analyze count data and a logistic GEE was used for proportions. Results: We observed short-term beneficial changes in the composition of the red complex of up to 3 months by treating subjects with AMOXMETTET. Similar short-term improvements with the same treatment were observed for Tannerella forsythia and Treponema denticola of the red complex. SURG had also shortterm beneficial effect on Porphyromonas gingivalis. No periodontal treatments applied to severely affected sites promoted the growth of Actinomyces. Smoking elevated counts of both the red and orange complex while bleeding on probing (BOP) and gingival redness were also predictors of more red complex counts. Comparatively similar findings were obtained by analyzing counts and by analyzing proportions. Conclusions: Although short-term reductions in the counts of the red complex were observed in sites that were treated with AMOXMETTET, long-term significant effects were not observed with any of the eight treatments. Poor oral hygiene in patients with severe chronic periodontitis diminished the beneficial effects of treatment. Keywords: microbiota; chronic periodontitis; periodontal therapy; antibiotics; multilevel analysis; NB GEE; fractional response methods (Published: 9 July 2013) Citation: Journal of Oral Microbiology 2013, 5: 20939 - http://dx.doi.org/10.3402/jom.v5i0.20939 Access the supplementary material to this article – see Supplementary files under Article Tools online. *The Chief Editor Ingar Olsen, has not had any part in the review and decision process for this paper.