Western Society of Periodontics

Clinical Studies

Volume Number 3, 1995

Mechanism of irrigation effects on gingivitis

The aim of this study was to confirm the benefit of irrigation on gingival inflammation and to explore the mechanism by which irrigation affects gingival inflammation. Selected for this study were 125 patients with the following criteria: more than 20 teeth, not more than four sites with probing depths (PD) deeper than 6 mm, more than 30% of bleeding on probing (BOP), and gingival inflammation. The patients were randomly assigned to one of four groups: Group 1 (G1) toothbrushing only; Group 2 (G2), toothbrushing and rinsing with 0.12% chlorhexidine (CHX) twice a day; Group 3 (G3), toothbrushing and irrigation with water once a day (irr H20); Group 4 (G4), toothbrushing and irrigation with 0.04% CHX once a day (irr CHX).Six sites per tooth were examined at baseline, three, and six months. BOP and PD were assessed using automated probes. Gingival index (GI) and plaque index (PI) also were assessed. Subgingival microbial samples were taken from sites with PD > 4 mm and with BOP at baseline. Groups were given a prophylaxis and oral hygiene instructions specific to the group. Plaque samples were collected at baseline, three, and six months.

Of the group, 104 patients completed all visits; dropouts reported unacceptable taste associated with CHX. There was a decrease in PI in patients using CHX in either group. G3 had minimal or no effect on PI. The GI was significant at three months in CHX groups. This trend continued for six months, but it was not significant. All groups showed a decrease in BOP at three months relative to baseline. It was statistically significant at six months for all treatment groups when compared with toothbrushing alone. PD remained essentially unchanged for all groups at three and six months. The magnitude of the benefit observed in sites with improvement in PI suggests that the effect of irrigation is additive to and perhaps independent of the inflammation improvement due to plaque reduction. The irri H2O group showed no correlation between plaque quantity and inflammation. The irri H2O was capable of decreasing inflammation independent of decrease in plaque. There was a decrease in microbes, not differentiated by treatment group. P. intermedius decreased significantly from baseline at three months in the CHX irrigation group and at six months in the irrigation and H2O group. At six months the H2O irrigation group had a significant increase in E corrodens. In conclusion, irrigation with water showed a minimal decrease in plaque, but improvement in clinical inflammation. Both irrigation groups showed a decrease in inflammation. [c.c.]