RESUMEN
The purpose of this investigation was to evaluate effect of local antibiotic therapy with metronidazole adjunctively to Scaling and Root Planning [SRP] mechanical or antibiotical treatment alone. This randomised double blind study was carried out in split-mouth design. Ten patients with moderate to severe adult periodontitis were selected. Each patient had to have at least 3 multi-root and 3 single-root nonadjacent teeth with a probing depth >/= 5[mm]. Randomly selected teeth were treated with application of 25% gel metronidazole [SRP+Elyzol]. A total of 141 site [= 5[mm]] were included. The clinical effects of treatment modalities were monitored over a period of 90 days. All three methods of treatment were effective and significantly reduced probing pocket depth and bleeding on probing and increasing clinical attachment level. No statistically significant differences were found between SRP and Elyzol alone. The t-test showed that the SRP+Elyzol group was significantly better than SRP or Elyzol alone. No statistically significant differences were found between multi-root and single-root teeth. There was also a significant improvement for SRP+Elyzol group over SRP and Elyzol alone at deep pockets [= 7[mm]] in comparison to moderate pockets. In teeth with advanced periodontitis area comparing to moderately involved sites, local metronidazole in combination with scaling and root planning seems to be more effective than SRP or local metronidazole alone