Optimal rinsing time for intra-oral distribution (spread) of mouthwashes

To investigate the intra-oral spread of an erythrosine mouthwash in relation to the rinsing period.

Thirty subjects were randomly divided into two equal groups and asked to rinse with 10 ml erythrosine mouthwash for cumulative periods of 15, 30 and 60 s (Group I) and 30, 60 and 90 s (Group II). Each rinsing session was followed by new plaque measurements. After rinsing plaque was finally assessed using the erythrosine mouthwash applied by means of a cotton swab.

In Group I there was a difference observed between the 15 s rinsing period and those of 30 and 60 s. Explorative analysis for Group I suggested that differences in both jaws and approximal sites on both vestibular and lingual surfaces appeared to have contributed to the overall difference seen between 15 and 30 s rinsing periods. Also, pre-molars and front teeth seem to have contributed to this observed difference. No differences were noted between rinsing sessions and cotton swab application for Group II or Groups I+II combined.

Rinsing for 30 s appeared to be sufficient for all plaque-covered surfaces of the dentition to come into contact with the mouthwash.