Influence of temperature on volumetric shrinkage and contraction stress of dental composites

• Influence of temperature on volumetric shrinkage and contraction stress was tested.
• Four commercially available dental composites were tested.
• Tests were carried out at 23, 30, 37, and 44 °C.
• Volumetric shrinkage increases with higher temperature.
• Contraction stress increases between 23 and 30 °C.

ObjectivesTo test the influence of temperature on contraction stress and volumetric shrinkage of Clearfil AP-X, Venus Diamond, Premise and Filtek Z250.MethodsVolumetric shrinkage measurements were carried out using mercury dilatometry, while a constraint tensilometer set-up was used for the measurement of contraction stress. Measurements were carried out with a composite temperature of 23, 30, 37, and 44 °C.ResultsVolumetric shrinkage increases with higher temperature. Premise and Venus Diamond show lower volumetric shrinkage than Clearfil AP-X and Filtek Z250. Clearfil AP-X shows the highest contraction stress which slightly increases with higher temperatures. The other composites only show an increase in contraction stress between 23 and 30 °C.SignificanceHeating of dental composites results in a higher volumetric shrinkage. However, the contraction stress does not change significantly due to increased temperature above 30 °C.