Effects of Immersion Disinfection on a Hydrophilic Vinyl Polysiloxane Impression Material
Objectives: To evaluate the effects of two disinfecting solutions and deionised water (control), on the mass change and solubility of a hydrophilic vinyl polysiloxane impression material (VPS, Aquasil Monophase, Dentsply), over long term immersion. Methods: Rectangular samples of VPS (40x10x1.5 mm) were prepared and immersed in 100ml of 1% sodium hypochlorite (NaOCl), 2% Perform ID (PID, 23oC only) and deionised water (DW - control) respectively, for 1 month (23oC) and 4 months (37oC), then moved to a drying oven, for 1 month at 23 or 37oC respectively. Mass gain/loss was measured gravimetrically at regular time intervals. Solubility was determined subsequently. (n=5 per solution/temperature). Results: All samples increased in weight in the three media, over the immersion period (Table 1), but with differing uptake profiles. Initially the samples in NaOCl gained less weight than those in DW, but after ~ 8 weeks, this rapidly increased (still rising at 4 months). At 24 hours, PID samples had the highest mass change. On desorption, the PID samples had not equilibrated; DW and NaOCl samples reached equilibrium within a day. The solubility of the NaOCl samples was higher compared to those in DW and PID, thus indicating that leachants and water were being lost from VPS Conclusions: NaOCl and particularly PID adversely affected the mass change of hydrophilic VPS after long term immersion, indicating that they can adversely affect its dimensional stability; PID showed the highest mass change.