The effect of a single episode of chlorhexidine irrigation on the gingival response to scaling and root planing.

The adjunctive effects of subgingival chlorhexidine irrigation on gingival response following scaling and root planing were investigated. Changes in clinical parameters, and microbial composition of subgingival plaque as monitored by dark-field microscopy were assessed in 12 patients over a period of 12 weeks. Two test sites and two matched control sites with probing depth ranging from 4 mm to 7 mm were selected in each patient. Oral hygiene instruction and a single episode of scaling and root planing were carried out. In addition test sites were irrigated with one mL of 0.2% chlorhexidine solution by the operator, while control sites were either irrigated with an equal volume of physiological saline or not irrigated. There were significant improvements in the clinical parameters with little difference between test and control sites. Between the beginning and the end of the study there was a marked reduction in the proportion of spirochaetes with a concomitant increase in coccoid organisms with, again, only minor differences between the test and the control sites. It was concluded that subgingival irrigation with a single application of 0.2% chlorhexidine did not enhance gingival healing, or delay recolonization of pockets by certain micro-organisms (as monitored by dark-field microscopy), when scaling and root planing had been thoroughly carried out immediately prior to irrigation.