The influence of viscosity on an encapsulated glass-ionomer restorative

Objectives: The aim of the study was to evaluate the influence of the viscosity on the performance of a glass ionomer dental restorative. Methods: Mean compressive fracture strengths and standard deviations and associated Weibull Moduli (m) were determined for an encapsulated restorative with varying powder/liquid mixing ratios manipulated in a Capmix or Rotomix. Scanning electron microscopy and image analysis was used to investigate the influence of the mixing method on pore distribution. Results: The compressive fracture strength data for the encapsulated restoratives (G95, G90 and G85) resulted in no significant differences between the means of groups prepared utilising the Capmix [110.1(21.8),110.6(20.2)and 96.3(15.6)] or the Rotomix [103.6 (20.5),105.3 (21.4)and 93.8 (15.4)] mechanical agitators using one way ANOVA (P<0.05). The image analysis studies highlighted that there was no reduction in pore distribution with the initial viscosity and mixing regime. Conclusion: The initial viscosity of the cement mass did not impact on performance and as a result it is likely that the capsule design of the restorative was inappopriate.