Dimensional stability of two impression materials after a 6-month storage period

Abstract

Objective: Oral rehabilitation success is enhanced by an accurate and reproducible final impression. The purpose of this study is to evaluate the dimensional changes of a polyether and addition silicone subjected to disinfection and/or sterilization after a long storage period.

Material and methods: Ninety samples were obtained from polyether Impregum^TM Penta^TM (3M ESPE^TM, Seefeld, Germany) and 90 of addition silicone Imprint^TM 4 Penta^TM Putty (3M ESPE^TM, Seefeld, Germany) according to ISO 4823:2000. The samples of each material were split to form three groups with 30 samples each: a control group, a hypochlorite group (disinfection) and an autoclave group (sterilization). Samples were stored in the Portuguese Institute for Quality for six months at 23 °C. Samples were measured by laser interferometry, according to the Michelson technique before calculating dimensional stability according ISO 4823:2000. A statistical analysis via a three-way mixed ANOVA was performed.

Results: Significant shrinkage of Impregum^TM Penta^TM was 0.77 ± 0.17% in the control group, 0.42 ± 0.19% in the hypochlorite group and 0.52 ± 0.28% in the autoclave group. For Imprint^TM 4 Penta^TM Putty, the control group had a shrinkage of 0.42 ± 0.12%, the hypochlorite group 0.36 ± 0.09% and the autoclave group 0.59 ± 0.13%.

Conclusions: The long-term storage of samples subjected to disinfection with 5.25% hypochlorite or autoclave sterilization can be used in a clinical setting as the dimensional changes are below the maximum permitted by the ISO 4823:2000, since there are no clinically significant changes in the dimension of the samples during the storage period.

Keywords:

• Elastomers
• sterilization
• laser interferometry

Acknowledgements

The authors would like to thank 3M ESPE Portugal for the materials and the Portuguese Institute of Quality for the use of the facilities.

Disclosure statement

No potential conflict of interest was reported by the authors.