Method: For this study one commercial (Silginat, SIL, #120401-135, Heraeus Kulzer) and one experimental alginate (EXP, B:0053, C:0028, 3M ESPE) replacement materials in 5:1 automix delivery were analyzed for their linear dimensional change according to ISO 4823:2000. Samples were analyzed after 1 h, 14 d and 84 d. 30 min after setting the materials were also tested for their gypsum compatibility in multiple pours by performing the gypsum compatibility test according to ISO4823:2000 for five subsequent times.
Result: Results and standard deviations obtained by one-way-Anova and Tukey Test (p<0.05) are shown below. Additionally, both materials fulfilled the gypsum compatibility test according to ISO 4823:2000 if poured five subsequent times.
Linear Dimensional Change [%] |
|||
Material |
1h |
14d |
84d |
SIL |
0.17(0.05)a |
0.21(0.02)a |
0.33(0.01)b |
EXP |
0.18(0.03)a |
0.20(0.01)a |
0.18(0.03)a |
Means with the same letter are statistically the same.
Conclusion: Both materials fulfill the ISO 4823:2000 criteria for linear dimensional change of a maximum of 1.5 % change even after 12 weeks of storage. Also, both materials were found to be capable of being poured multiple times as they maintained their gypsum compatibility according to ISO 4823:2000 even after five consecutive pours. While no statistically significant differences between materials were found at 1h and 14d SIL shows a stronger change of dimensions after 84d. EXP showed no change within 12 weeks so it can be assumed that the material will remain stable for an even longer time than tested here. Long term dimensional stability of impression materials allows for storage of the impression, e.g. for multiple pours or to prepare several temporaries in case of long term temporization cases.