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

Area of Science:

• Dental Materials Science
• Prosthodontics
• Biomaterials Engineering

Background:

• Accurate occlusal records are fundamental for successful prosthodontic restorations.
• Dimensional stability of interocclusal recording materials is critical to prevent inaccuracies in the final prosthesis.
• Previous studies have shown variability in the dimensional stability of different classes of impression materials.

Purpose of the Study:

• To compare the linear dimensional and weight changes of four interocclusal recording materials: polyether (Ramitec), two polyvinylsiloxane variants (O-Bite, Jet Bite), and dimethacrylate (LuxaBite).
• To evaluate the effectiveness of these materials in maintaining accurate occlusal records over time (1 hour, 24 hours, 1 week).

Main Methods:

• Twenty samples of each material were prepared and subjected to a 500-g weight.
• Dimensional changes were measured using a stereomicroscope.
• Weight changes were assessed using an electronic scale at 1-hour, 24-hour, and 1-week intervals.
• Statistical analyses included one-way ANOVA and repeated measures ANOVA.

Main Results:

• Polyvinylsiloxane (Jet Bite) exhibited the highest dimensional stability with minimal changes (0.49% at 1 hour, 0.52% at 24 hours, 0.50% at 1 week).
• Another polyvinylsiloxane (O-Bite) showed higher dimensional changes (1.13% at 1 hour, 1.51% at 24 hours, 1.50% at 1 week).
• Polyether (Ramitec) had significant initial variation (3% at 1 hour), while dimethacrylate (LuxaBite) showed expansion followed by contraction linked to polymerization and weight loss.

Conclusions:

• Polyvinylsiloxane materials demonstrated superior dimensional accuracy and stability among the tested materials.
• Timely mounting of casts after recording significantly improves accuracy, emphasizing the importance of minimizing storage time.
• A strong correlation exists between weight changes and dimensional alterations across all materials, impacting clinical reliability.