An In-vitro study to compare the dimensional stability and surface hardness of elastomeric bite registration materials at various time intervals

Introduction: Interocclusal records are essential to relate dental casts to an articulator. The advance of the polymer science introduced elastomeric interocclusal recording materials in the field of dentistry. But their properties are not completely understood. Aim: To evaluate and compare the dimensional stability and surface hardness of two commercially available Vinyl Polysiloxane and Polyether elastomeric bite registration materials at various time intervals. Materials and Methods: The materials tested were ImprintTM bite, Futar® D and RamitecTM. A total of 30 specimens were made, 10 each from three elastomeric bite registration materials. A travelling microscope was used to measure dimensional change and Shore-A durometer was used to measure surface hardness. The measurements were collected at the time intervals of 1, 24, 48 and 72 hours and mean values were taken for statistical analysis. Statistical analysis was performed by one-way ANOVA test and post hoc analysis by Bonferroni to compare the percentage of change over a period of time. Results: Result showed that significant percentage of dimensional change was noted in all the three materials. Vinyl Polysiloxane showed significant dimensional change up to 48 hours. Polyether showed less dimensional change in the first 24 hours but later showed significant expansion. All the bite registration materials attained their maximum surface hardness in 48 hours. Vinyl Polysiloxane bite registration materials recorded the highest surface hardness.