Comparative evaluation of surface hardness of different provisional restorative materials at different time intervals-An in vitro study

Background: It is essential to comprehend the mechanical characteristics of temporary restorative materials for their clinical application, aiding clinicians in selecting appropriate materials based on specific patient needs and expected clinical conditions. Aim: This in vitro study aimed to evaluate and compare the hardness of four different provisional restorative materials used in dental practice under dry and wet conditions. Material and Methods: Materials tested included auto-polymerizing PMMA, heat-cured PMMA, Bis-acryl composite, and Bis-GMA composite. Each material was assessed using Rockwell hardness testing, both initially and after immersion, in artificial saliva for one week. Split mold of dimension 50 mm diameter and 3 mm thickness was used to make specimens of each group. Specimens were prepared according to manufacturer specifications and subjected to hardness testing using 50 g load and a 12.70 mm ball indenter. Because of the data's non-normal distribution, non-parametric tests were used for statistical analysis. Results: Results showed significant variations in hardness among the materials both in dry and wet conditions. Bis-GMA Composite and Bis-acryl Composite Resin exhibited the highest hardness values in both conditions, followed by Heat activated PMMA, auto-polymerizing PMMA. Wet conditions generally resulted in decreased hardness across all materials compared to dry conditions. Conclusion: The results of this investigation indicate that, in terms of hardness, composite-based materials are superior to PMMA-based materials. As a result, they ought to be the material of choice for temporary restorations.