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

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

Material And Methods: 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.

Results: 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.

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