Physicochemical and Mechanical Characterization of Two Self-Curing Composite Resins for Direct Provisional Prostheses

Area of Science:

• Dental Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Temporary dental prostheses require materials with specific mechanical and physicochemical properties for optimal function and longevity.
• Bis-GMA (Bis-GMA) and Bis-EMA (Bis-EMA) based composites are commonly used in dental applications, but their comparative performance in temporary prostheses needs detailed evaluation.
• Understanding the differences in material properties is crucial for selecting the appropriate composite for specific clinical scenarios.

Purpose of the Study:

• To conduct an in vitro comparative analysis of the physicochemical and mechanical properties of two self-curing dental composites: Structur 3 (Bis-GMA based) and Visco III (Bis-EMA based).
• To evaluate properties including flexural strength, toughness, hydrophilicity, density, microhardness, water absorption, and wear resistance.
• To determine the suitability of each composite for fabricating temporary dental prostheses based on their performance characteristics.

Main Methods:

• In vitro experimental study comparing Structur 3 and Visco III dental composites.
• Evaluation of flexural strength, toughness, displacement to fracture, microhardness (HV0.5), water absorption (µg/mm³), wear (wear channel area), density (g/cm³), and contact angle (hydrophilicity).
• Fractography analysis was performed to assess fracture behavior.

Main Results:

• Structur 3 demonstrated higher flexural strength (127 ± 16 MPa) and toughness (36.52 ± 9.20 mJ) compared to Visco III (103 ± 25 MPa and 16.55 ± 7.55 mJ, respectively).
• Visco III exhibited superior microhardness (17.045 ± 0.93 HV0.5), lower water absorption (11.2 ± 0.4 µg/mm³), and less wear (0.031 ± 0.013 mm²) than Structur 3.
• Visco III was denser (1.5917 ± 0.006 g/cm³) and both composites showed brittle fractures and similar hydrophilicity (<90° contact angle).

Conclusions:

• Visco III is recommended for applications prioritizing durability and resistance due to its higher microhardness, lower water absorption, and reduced wear.
• Structur 3 is better suited for provisional prostheses requiring flexibility, such as those with pontics, or when high esthetic quality is paramount.
• Filler composition, including radiopaque elements like aluminum and barium in Visco III, influences the observed property differences.