Bonding Ability and Mechanical Properties of 4-META/MMA-based Resins Incorporating PolyHEMA/TMPT-particles

Objectives: Aiming at achievement of bio-active dental resins, we have developed novel poly(2-hydroxyethyl methacrylate/trimethylolpropane trimethacrylate) particles (polyHEMA/TMPT-particles) as the non-biodegradable carrier for antimicrobials or growth factors. Previously, we reported that incorporation of FGF-2-loaded polyHEMA/TMPT-particles into 4-META/MMA-based adhesive resin was effective to provide the ability to release FGF-2 and to promote tissue regeneration. The aim of this study was to evaluate the influences of incorporation of polyHEMA/TMPT-particles on dentin bonding ability and mechanical properties of 4-META/MMA-based adhesive resins.
Methods: The experimental adhesive resin was prepared by adding the polyHEMA/TMPT-particles (ave. diameter: 8.7 µm) to the powder of a commercial 4-META/MMA-TBB resin (Super Bond, Sun Medical Inc; SB) at 10 or 30 wt%. A metal rod (φ3 mm) was adhered to the dentin surface of bovine tooth using the experimental adhesive resin, and a shear bond test was performed after immersion in distilled water for 24 hours. To assess the mechanical properties, cured specimen was immersed in distilled water for 24 hours or 7 days, and the maximum stress was measured by a three-point bending test. SB without addition of the particle served as the control.
Results: There were no significant differences in the shear bond strength among two experimental resins and the control (p>0.05, Tukey’s HSD test). By the three-point bending test, no significant differences in the maximum stresses were observed among all specimens (p>0.05, Kruskal-Wallis test). After immersion in water for 7 days, the maximum stresses of SB incorporating polyHEMA/TMPT-particles exhibited no significant reduction (p>0.05, Kruskal-Wallis test).
Conclusions: The results of this study indicated that incorporation of fine-sized polyHEMA/TMPT-particles showed no adverse influences on bonding ability and mechanical properties of 4-META/MMA-based resins, suggesting acceptability of the experimental resins for clinical use.