Novel self-healing dental resin with microcapsules of polymerizable triethylene glycol dimethacrylate and N,N-dihydroxyethyl-p-toluidine.

Abstract Objective Bulk fracture is one of the primary reasons for resin-based dental restoration failures. To date, there has been no report on the use of polymerizable dental monomers with acceptable biocompatibility to develop a resin with substantial self-healing capability. The objectives of this study were to: (1) develop a self-healing resin containing microcapsules with triethylene glycol dimethacrylate (TEGDMA)- N , N -dihydroxyethyl- p -toluidine (DHEPT) healing liquid in poly(urea-formaldehyde) (PUF) shells for the first time, and (2) determine the physical and mechanical properties, self-healing efficiency, and fibroblast cytotoxicity. Methods Microcapsules of polymerizable TEGDMA-DHEPT in PUF were prepared via an in situ polymerization method. Microcapsules were added into a BisGMA-TEGDMA resin at microcapsule mass fractions of 0%, 5%, 10%, 15% and 20%. A flexural test was used to measure composite strength and elastic modulus. A single edge V-notched beam method was used to measure fracture toughness K IC and self-healing efficiency. Results Flexural strength and elastic modulus (mean ± sd; n  = 6) of resin containing 5–15% microcapsules were similar to control without microcapsules ( p  > 0.1). Adding microcapsules into the resin increased the virgin K IC , which was about 40% higher at 15% microcapsules than that with 0% microcapsules ( p IC . A self-healing efficiency of about 65% in K IC recovery was obtained with 10–20% microcapsules. All specimens with 0–20% microcapsules had fibroblast viability similar to control without resin eluents ( p  > 0.1). Significance Self-healing dental resin containing microcapsules with polymerizable TEGDMA-DHEPT healing liquid in PUF shells were prepared for the first time with excellent self-healing capability. These microcapsules and self-healing resins containing them may be promising for dental restorations to heal cracks/damage and increase durability.