In Vitro Evaluation of Time-Dependent Linear Dimensional Changes in Four Interocclusal Recording Materials

This study aimed to evaluate and compare the linear dimensional and weight changes of four types of interocclusal recording materials, polyether (Ramitec), two polyvinylsiloxane variants (O-Bite and Jet Bite), and dimethacrylate (LuxaBite), at 1-hour, 24-hour, and 1-week intervals to assess their effectiveness in maintaining accurate occlusal records.

20 samples of each interocclusal recording material were prepared using a stainless-steel die with a test block and ring mold. Each sample, measuring 30 mm in diameter and 2 mm in thickness, was subjected to a 500-g weight for five minutes. Dimensional changes were measured using a stereomicroscope, and weight changes were assessed with an electronic scale at the specified intervals of 1 hour, 24 hours, and 1 week. Statistical analyses such as one-way analysis of variance (ANOVA) and repeated measures ANOVA, were used to compare the data using SPSS software version 26.

Among the materials evaluated, polyvinylsiloxane material (Jet Bite) demonstrated the highest accuracy and dimensional stability with minimal changes over time (0.49% at 1 hour, 0.52% at 24 hours, and 0.50% at 1 week). The second polyvinylsiloxane (O-Bite) exhibited slightly higher dimensional changes (1.13% at 1 hour, 1.51% at 24 hours, and 1.50% at 1 week). The polyether material (Ramitec) showed significant initial variation (3% at 1 hour) but minimal changes thereafter. The dimethacrylate material (LuxaBite) expanded at 1 hour and then contracted, correlating with weight loss due to polymerization.

Among the materials tested, polyvinylsiloxane demonstrated the highest dimensional accuracy and stability. Accuracy was markedly improved when casts were mounted shortly after recording, highlighting the importance of minimizing storage time. Additionally, all materials exhibited a significant correlation between weight changes and dimensional alterations, suggesting that shrinkage or expansion can impact clinical reliability. Therefore, selecting appropriate recording materials and ensuring timely mounting of the cast are crucial for achieving optimal prosthodontic results.