EFFECT OF TWO-DISINFECTION TIMES ON DIMENSIONAL ACCURACY OF VINYLPOLYSILOXANE IMPRESSIONS.

Purpose: To evaluate linear dimensional changes of vinylpolysilixane impressions after immersion disinfection. Materials and Methods: A standardized steel master cast fabricated to provide dental replica of two teeth prepared for complete crown with 10-degree convergence one represent canine and other represent molar with edentulous interposed space 42.1 mm. Auto polymerized resin perforated custom tray with 2 mm spacer constructed from master cast. The trays paints with adhesive, and allowed to dry for 60 seconds before obtaining the impressions.Regular body vinylpolysilixane impression material (Elite HD+ regular body zhermack) used for fabrication of 30 impressions. A 20 impressions act as control (10 of them left in atmosphere for 30, 60 minutes and other 10 immersed in distilled water for 30, 60 minutes before pouring). Other 10 impressions (test group) immersed in a glutaraldehyde disinfectant solution (MD 520 impression disinfection) for 30 and 60 minutes. All impression poured with extra hard dental stone. Obtained casts evaluated for linear dimensional changes using a digital caliper. Data tabulated and statistically analyzed using one-way analysis of variance with a significance level set at = 0.05. Results: The highest dimensional change value was recorded after immersion impressions in distilled water for 60 minutes while, the lowest value was recorded after immersion in disinfectant solution for 60 minutes. There is no significant difference in dimensional changes between control groups and test group at both immersion times. Conclusion: Under the limitations of present study, tasted disinfection times (30 minutes & 60 minutes) has no effect on dimensional accuracy of tested impression material.