Objectives Duplicating materials must routinely accurately reproduce the details of dental casts and thus contribute significantly to the close adaptation and success of a removable prosthesis or fixed indirect restoration. It is important to establish the long-term dimensional stability of polyvinyl siloxane materials (PVS) as they are widely used in dental technology and over the duration of a course of treatment, are stored under dental laboratory conditions. The dimensional stability of four PVS duplicating materials was investigated over a 13-week period. Materials and methods Forty PVS duplicate moulds of a partially dentate maxillary arch were produced from four materials (Elite double 8, Gemini transparent, C & J pourable silicone and Z Dupe). Three dimensions were measured in triplicate at baseline 1, 5, 9 and 13 weeks using computerised image analysis. Half of the specimens were measured following storage at room temperature (21 ± 2 °C) and half at 37 °C to represent storage in hot climates. Specimens for scanning electron microscopy were prepared by duplicating a rugosity standard. Results At room temperature two materials Elite Double 8 and Z Dupe showed no statistically significant dimensional change, the other two materials showed a slight increase of dimensions. Specimens stored at 37 °C showed greater differences in dimensions with Z Dupe showing statistically significant shrinkage. SEM investigation showed no surface deterioration of two materials. Conclusions None of the materials showed a change in dimension greater than 2% and the four PVS materials showed good dimensional stability over the time period of the study.
|Journal||Journal of Dentistry|
|Publication status||Published - Jun 2008|