Longitudinal effect of non-surgical treatment and systemic metronidazole for 1 week in smokers and non-smokers with refractory periodontitis: A 5-year study

Background: Periodontitis consists of a mixture of diseases, most of which respond favorably to traditional mechanical therapy. It is now recognized t hat advanced periodontitis does not always respond to conventional manageme nt with scaling, periodontal surgery, and oral hygiene measures. However, v arious types of antibiotics given systemically or locally improve the succe ss rate of periodontal therapy. In short-term studies, it has been shown th at metronidazole, when systemically administered after debridement, resulte d in treatment benefits including less need for surgical intervention. Methods: In this double-blind study, we evaluated periodontal treatment inv olving initial non-surgical treatment, systemic administration of metronida zole for 1 week, and then follow-ups for scaling and root planing every 6 m onths, for 5 years. The study population consisted of 64 subjects (37 smoke rs and 27 nonsmokers), mean age 36.3 (+/-3.0 SD) years, with severe periodo ntal disease. After initial scaling and root planing, patients were randoml y assigned to the intervention or placebo groups: 400 mg metronidazole or a placebo administered at 8-hour intervals for 1 week. The participants unde rwent an extensive clinical periodontal examination. Gingival crevicular fl uid (GCF) was analyzed for spirochetes and granulocytes. Samples were cultu red for Actinabacillus actinomycetemcomitans (A.a.), Porphyromonas gingival is (P.g.), and Prevotella intermedia (P.i.). Results: The number of patients infected with A.a., P.g., P.i., and spiroch etes decreased during the study. Most patients who harbored spirochetes at the end of the study had these microorganisms at the beginning. Smokers res ponded less favorably to periodontal therapy than non-smokers. Non-smoking patients who required only non-surgical therapy in the intervention group s howed statistically significant improvement in the clinical parameters afte r 5 years. Patients with complete healing, defined as the absence of inflam ed sites greater than or equal to 5 mm, after 5 years were found only in th e intervention group. The patients considered healthy after 5 years were th e same patients found to be healthy after 6 months. Conclusions: Decisive factors in the sustained long-term improvement of pat ients who respond satisfactorily to treatment are probably initial scaling and root planing; a brief course of metronidazole; and regular follow-up ex aminations at 6-month intervals for oral hygiene and scaling and root plani ng.