Chlorhexidine gluconate mouthwashes as a surfactant for addition-reaction silicone impressions

Addition-reaction silicone impression (PVS) materials are hydrophobic. Hydrophobicity of the impression material may interfere with the wetting of the tooth, resulting in void formation. The study investigates whether conditioning teeth with Chlorhexidine-gluconate based mouthwashes can reduce the hydrophobicity and the number of voids on PVS impressions. Impression material contact angle specimens on bovine tooth surfaces were measured using a Reflex Microscope. PVS impressions (President) were made of untreated bovine teeth in three groups (1, 2 and 3) and fourth group used Impregum polyether impression material: Group I was used as a control group, and original and mint flavoured Corsodyl (Chlorhexidine) mouthwashes were used as clinical surfactants in Groups 2 and 3, respectively. Contact angle readings were recorded on each side of every impression in each of the four groups and compared by an analysis of variance. In the second part of the study, the numbers of air voids on impression surfaces were visually recorded. The proportions of air voids in the groups were compared using a Chi-squared test. The mean angle for Group 3 with mint flavoured Corsodyl mouthwash was significantly smaller than that of any of the other groups (P < 0.05). The only statistically significant (P < 0.01) comparisons of the proportions of air voids were between Group 4 and each of the other experimental groups, with the percentage of voids being significantly greater in Group 4. Although Corsodyl mint significantly reduced the mean contact angle it did not significantly reduce the percentage of voids on impression surfaces.