Topical metronidazole application compared with subgingival scaling. A clinical and microbiological study on recall...

The aim of this study was to compare the topical application of a metronidazole 25% dental gel with subgingival scaling. 30 patients from the recall program participated in this open randomised study with split-mouth design. Pocket probing depths (PPD) and bleeding on probing (BOP) were measured before and 2, 12 and 24 weeks after the end of the treatment period. In addition, subgingival plaque samples were taken from all mesial sites and analysed with dark-field microscopy. All patients had at least 1 tooth in each quadrant with a PPD of 5 mm or more that should bleeding on probing, when entering the study. The treatment consisted of 2 applications of the dental gel in 2 randomly selected quadrants (on days 0 and 7) as well as simultaneous subgingival scaling of the remaining quadrants. Oral hygiene instruction was given on day 21. The average PPD and the average frequency of BOP were calculated for all sites with an initial PPD of 5 mm or more and continued at each examination, using the same sites. The statistical analyses showed that both treatments were effective in reducing PPD and BOP over the 6-month period. At the end of the follow-up period, the mean reduction in PPD was 1.3 mm after gel treatment and 1.5 mm after subgingival scaling. BOP was reduced by 35% and 42%, respectively. No significant differences between the 2 treatments were detected. Dark-field microscopy showed a shift toward a more healthy microflora for both treatment modalities; this persisted throughout the 6-month period. Application of a 25% metronidazole dental gel on recall patients seems to be as effective on the investigated clinical and microbiological parameters as subgingival scaling.