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 that advanced periodontitis does not always respond to conventional management with scaling, periodontal surgery, and oral hygiene measures. However, various types of antibiotics given systemically or locally improve the success rate of periodontal therapy. In short-term studies, it has been shown that metronidazole, when systemically administered after debridement, resulted in treatment benefits including less need for surgical intervention. Methods: In this double-blind study, we evaluated periodontal treatment involving initial non-surgical treatment, systemic administration of metronidazole for 1 week, and then follow-ups for scaling and root planing every 6 months, for 5 years. The study population consisted of 64 subjects (37 smokers and 27 nonsmokers), mean age 36.3 (+/-3.0 SD) years, with severe periodontal disease. After initial scaling and root planing, patients were randomly assigned to the intervention or placebo groups: 400 mg metronidazole or a placebo administered at 8-hour intervals for 1 week. The participants underwent an extensive clinical periodontal examination. Gingival crevicular fluid (GCF) was analyzed for spirochetes and granulocytes. Samples were cultured for Actinabacillus actinomycetemcomitans (A.a.), Porphyromonas gingivalis (P.g.), and Prevotella intermedia (P.i.). Results: The number of patients infected with A.a., P.g., P.i., and spirochetes decreased during the study. Most patients who harbored spirochetes at the end of the study had these microorganisms at the beginning. Smokers responded less favorably to periodontal therapy than non-smokers. Non-smoking patients who required only non-surgical therapy in the intervention group showed statistically significant improvement in the clinical parameters after 5 years. Patients with complete healing, defined as the absence of inflamed sites greater than or equal to 5 mm, after 5 years were found only in the intervention group. The patients considered healthy after 5 years were the same patients found to be healthy after 6 months. Conclusions: Decisive factors in the sustained long-term improvement of patients who respond satisfactorily to treatment are probably initial scaling and root planing; a brief course of metronidazole; and regular follow-up examinations at 6-month intervals for oral hygiene and scaling and root planing.