Repeated local metronidazole-therapy as adjunct to scaling and root planing in maintenance patients

The purpose of this investigation was to evaluate the effect of local antib iotic therapy with metronidazole adjunctively to scaling and root planing ( SRP) versus mechanical treatment alone. 30 maintenance-patients were includ ed in this single-blind study. The subjects had to comply with the followin g criteria: 2 non-adjacent sites with a probing depth greater than or equal to 6 mm with bleeding on probing in separate quadrants, no periodontal the rapy within the last 3 months, and no antibiotic therapy within the last 6 months. After randomization, the study sites were assigned to one of the fo llowing 2 treatments: SRP plus subgingival application of metronidazole 25% dental gel (Elyzol(R)) 5X during 10 days (test site) or SRP alone (control site). Subgingival microbiological samples were taken prior to, and 21 day s and 3 months after scaling. The samples were analyzed with a commercial c hair-side ELISA (Evalusite(R)) for Porphyromonas:gingivalis, Prevotella int ermedia and Actinobacillus actinomycetemcomitans. Probing pocket depth (PPD ), attachment level (AL) and bleeding on probing (BOP) were recorded at bas eline and 3 months later. PPD reduction and AL-gain were statistically sign ificant (p<0.001) after both treatments. However, there were no statistical ly significant differences between them. The same observation was made for BOP. P. gingivalis was reduced significantly after both treatments without statistically significant differences. P. intermedia was reduced significan tly only after SRP. A. actinomycetemcomitans, was not reduced significantly after either treatment. In conclusion, the repeated local application of m etronidazole as an adjunct to SRP and the mechanical treatment alone showed similar clinical and microbiological effects without statistically signifi cant differences with the exception of P, intermedia.