Mechanical Strength of 4-META/MMA-TBB Resin Containing Brazilian Green Propolis

Objectives: 4-META/MMA-TBB resin is widely used in clinical dentistry as a dental adhesive due to its high dentin adhesion, excellent marginal sealing, and good biocompatibility. However, it lacks sufficient ability to promote reparative dentin formation. To address this limitation, we focused on propolis as a method to enhance the reparative dentin-forming ability of the resin. Brazilian Green Propolis (BGP) is known for its anti-inflammatory properties and dentin-calcifying effects. This study aimed to evaluate the impact of combining BGP with 4-META/MMA-TBB resin on its mechanical strength.
Methods: 4-META/MMA-TBB resin (Super Bond, Sun Medical, Shiga, Japan) containing 0.5-10 wt% BGP to MMA was used. Conventional Super Bond (Sun Medical, Shiga, Japan) was used as the control. Rod-shaped specimens (2×2×25 mm) were prepared according to ISO 4049 standards using a mixing method and stored at 37°C in a humid environment for 24 hours.
Subsequently, the three-point bending strength was measured using a universal testing machine (EZ-graph, Shimadzu Corporation, Kyoto, Japan) at a crosshead speed of 1 mm/min, with a fulcrum distance of 20 mm (n=5).
Additionally, the Vickers hardness test was performed using a hardness tester (HMV, Shimadzu Corporation, Kyoto, Japan) with a test force of 1.961N applied for 10 seconds (n=5).
The experimental results were analyzed using Dunnett's test (p < 0.05).
Results: The 4-META/MMA-TBB resin with BGP showed no significant difference in three-point bending strength compared to the control. On the other hand, a significant increase in Vickers hardness was observed in the 10 wt% BGP group compared to the control.
The results indicate that BGP-doped 4-META/MMA-TBB resin demonstrates comparable mechanical strength to the conventional resin.
Conclusions: It was suggested that BGP does not affect the mechanical strength of 4-META/MMA-TBB resin.