Fracture Toughness of Resin Pit and Fissure Sealants

Objective: A mechanical property of resin pit and fissure sealants with and without titanium dioxide was evaluated and compared by means of fracture toughness. Method: Bis-GMA/TEGDMA-based experimental sealant was prepared by incorporating titanium dioxide at 0.5% by weight in order to make the sealant appear opaque. The fracture toughness (KIc) of the titanium dioxide incorporated resin sealant and a control sealant was measured by use of a single edge notch technique (SEN). SEN bars (25x5x2.5 mm) of those resin sealants with a crack length of 2.5 mm were subjected to a three-point loading test at a crosshead speed of 1 mm/min. The bars were loaded to failure on a 20 mm span. Ten specimens were tested for each group and results were analyzed by a student t test (alpha = 0.05). Result: There was a significant difference (p<0.05) in KIc values between the two resin sealants. The average KIc for resin sealant without titanium dioxide was 0.61±0.09 MPa m(1/2), while that of resin sealant with titanium dioxide was 0.71±0.06 MPa m(1/2). Conclusion: The resin sealant with titanium dioxide demonstrated higher fracture toughness suggesting more energy consumed before the crack started. The study was supported by Ratchadaphisek-somphot Endowment Fund.