Effect of Incorporation of Self-Healing Microcapsules to Experimental Resin Composite on Some Mechanical Properties

Document Type : Original Article

Authors

1 Demonstrator at Biomaterials Department, Badr university.

2 Associate Professor at Biomaterials Department, Al Azhar university for Girls.

3 Proffessor at polymer chemistry and pigments Department , National Research Center

4 Lecturer at Biomaterials Department, Al Azhar university for Girls.

Abstract

Purpose: The present study aimed to investigate the effect of incorporation of the new Triethylene glycoldimethacrylate and N,N-Bis(2-hydroxyethyl)-p-toluidine (TEGDMA)- (DHEPT) in polyurea formaldehyde (PUF) micro-capsules into an experimental dental resin composite on the flexural strength and fracture toughness and the evaluation of its self- healing efficacy. Materials and Methods: Polyurea formaldehyde microcapsules were synthesized by insitu polymerization technique, encapsulating a triethylene glycol dimethacrylate and dihydroxy ethyl para toluidine (TEGDMA–DHEPT) as a healing liquid, then experimental composite resin is prepared. Microcapsules are incorporated in the resin composite with concentrations 0%, 2.5%, 5%, 7.5% and 10%, then experimental resin composite specimens were fabricated. Fracture toughness and flexural strength were examined by three point loading using universal testing machine till fracture. The fracture toughness was evaluated by using single edge V-notched beam method, self healing efficacy is evaluated as the ratio between the healed fracture toughness and the virgin fracture toughness. Results: Regarding flexural strength results, it was found that the 0% group has the highest flexural strength while the 10% group had the lowest flexural strength. On the other hand, on evaluating the results, of 7.5% group it was found that this concentration did not affect the flexural strength remarkably. Regarding the virgin fracture toughness results, 0% group has the highest flexural strength, while the 10% group the lowest flexural strength, specimens were fractured and healed, then fractured again to measure the healed fracture toughness, on examining the results of the healed fracture toughness, it was found that no significant difference between 0% and 2.5% as no healing occur at such specimen, Also the results showed that the highest healed fracture toughness was in 5%, followed by 7.5%, followed by 10%. The self-healing efficacy increased to a recovery of about 75% in KIC when the microcapsule mass fraction was increased from 5% to 7.5% till reaching 10% concentration. Conclusions: In light of restoration fracture as one of the primary failure reasons, the novel self-healing dental composite may be promising to heal crack damages and to prolong the durability of the restoration clinically.

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