Method: The study was a randomized blinded clinical trial. Eligible patients underwent a pre-clinical period in order to eliminate factors that could interfere with the proper plaque control. Forty-five non dental students with healthy gingival (maximum 5% of sites showing gingival bleeding) were randomized into four groups according to the frequency of oral hygiene (every 12h, 24h, 48h or 72h). Plaque Index (PLI) and Gingival Index (GI) were evaluated by two trained examiners at baseline, 15 days and 30 days.
Result: 3 patients quit the study, one from the 12h group and two from the 48 h group. Regarding the PLI, the 12h group showed no changes during the experimental period. The other groups (24h, 48h, and 72h) showed a significant increase in the average of PLI between the baseline and 15 days, with the maintenance of average scores of plaque at 30 days. No significant difference was found between the 24h, 48h, and 72h groups on PLI. Some different behavior was observed in relation to the GI. In the 12h and 24h groups, the GI average remained similar throughout the experimental period. In contrast, there was an increase in the GI mean between baseline and 15 days, remaining stable until 30 days in the 48h and 72h groups. There were no changes in the frequency of the sites with score 2 of the GI (presence of gingival bleeding) in the 12h and 24h groups throughout the study, whereas in the 48h and 72h groups an increase was observed.
Conclusion: The frequency of oral hygiene of 24h is compatible with the maintenance of gingival health