Polymerization shrinkage strain of interocclusal recording materials

ObjectivesThe aim of this in vitro study was to investigate the polymerization shrinkage behavior and to measure the polymerization shrinkage-strain of interocclusal recording materials.MethodsThe materials investigated in this study were five polyvinylsiloxane (Imprint™ Bite, Silagum Automix Bite, O-Bite, Blu-Mousse® Classic and Exabite II), one polyether (Ramitec) and one dimethacrylatebased (Luxabite) materials. The polymerization shrinkage values of ten specimens for each material were measured by the Bonded-disk method at 1, 3, 5, 7 and 10 min after mixing at 37 °C. The amount of shrinkage-strain (%) was derived and all data were statistically analyzed by one-way ANOVA and the multiple comparison Scheffé test (α = 0.05).ResultsThe representative shrinkage-strain kinetic graphs showed that all specimens shrank immediately, except Luxabite which expanded for the initial few seconds. After that, the shrinkage-strain values increased in the magnitude up to 10 min, but its rate decreased gradually with time. The shrinkage-strain values (0.18 ± 0.03–0.16 ± 0.03%) of O-Bite at 5, 7 and 10 min were significantly lower than the other materials, but Luxabite exhibited the highest values (3.10 ± 0.17–3.30 ± 0.16%).SignificanceThe interocclusal recording materials investigated presented significantly different polymerization shrinkage-strain kinetics and showed dimensional changes even after the setting time indicated by respective manufacturers.