Aim: Superiority of the temporary provisional crown materials have not been established in terms of their insulative property.
Purpose: This experimental study was designed to compare the relative thermal insulative property of four different provisional crown materials.
Materials and Method: For this four provisional crown materials were taken i.e. poly methyl methacrylate, poly ethyl methyl methacrylate, bis-acrylate and urethane dimethacrylate. For testing purpose a machine was specially designed in which the samples made up of these provisional crown materials were tested. For all the materials 10 samples were fabricated and every sample was tested at temperatures of 50oC, 55oC and 60oC respectively. Samples of equal dimension were fabricated with the help of stainless steel die of dimension 4cm length x 2.5cm width x 3mm thickness. The
temperature differences were recorded for each sample at these specific temperatures with the help of 6 channel thermocouple and the readings were tabulated accordingly.
Results: the analysis of variance of temperature change in different materials at different heater temperatures as well as for overall assessment was done. It was observed that Polyethyl methyl methacrylate had temperature change of lowest order in all the simulations while Urethane dimethacrylate had the temperature change of highest order in all the simulations. Polymethyl methacrylate and Bis-Acrylic had temperature change values of middle order. For all the combinations, mean difference was found to be significant statistically (p<0.001). Maximum difference was observed between PEMMA and UDMA. Minimum difference was observed between Bis-Acrylic and UDMA at 50oC and 60oC as well as overall assessment and between PMMA and Bis-acrylic at 55oC.
Conclusion: After the final testing of the 4 provisional crown materials, following was the relative degree of insulation that a temporary crown material could provide:
UDMA > Bis-Acrylic > PMMA > PEMMA
Tanmay Srivastava et al.2016, Comparison of Thermal Insulative Property of Various Provisional Crown Materials: An Invitro Study. Int J Recent Sci Res. 7(11), pp. 14210-14216.