Effect of Storage Time on Tear Strength of Extended-Pour Irreversible Hydrocolloid Impression Materials

Objective: the aim of this in vitro study was to evaluate the effect of prolonged storage times on the tear strength of extended-pour irreversible hydrocolloid impression materials. material-method: eighty four specimens were fabricated from five commercial extended-pour irreversible hydrocolloid impression materials (blueprint xcreme, hydrogum 5, kromopan, alginmax and alginelle) as well as one experimental formula in accordance with the iso 21563:2013 standard effective for irreversible hydrocolloid impression materials. specimens were randomly divided in two groups for each impression material (n=7) and subjected to tear strength test immediately (base line) or after 120 hours of storage. tear strength values were obtained in n/mm and data were analysed with two-way anova (irreversible hydrocolloid brand, storage time). multiple comparisons were performed with tukey’s test (p=0.05). results: the tear strength of the extended-pour irreversible hydrocolloid impression materials were affected by brand (p<0.0001) and brand-storage time interaction (p=0.005). storage time did not influence the tear strengths of the extended-pour irreversible hydrocolloid impression materials tested except alginmax whose mean tear strengths increased after 120 hours of storage (p<0.05). at base line measurements blueprint xcreme provided the highest mean tear strength values (1.08±0.19 n/mm) whereas alginelle provided the lowest mean tear strength values (0.51±0.3 n/mm). hydrogum 5 provided the highest tear strength values after 120 hours of storage (1.15± 0.12 n/mm) whereas alginelle provided the lowest mean tear strength values (0.55±0.04 n/mm). conclusions: all commercial extended-pour irreversible hydrocolloid impression materials tested maintained their tear strengths after 120 hours of storage.