| 0516 Fracture Resistance of Light-activated Restorative Materials | ||
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T. HOOSHMAND1, N. NASR1, A. KESHVAD2, and I. HARIRIAN3, 1 Dental Research Center / Research Center of Science & Technology in Medicine, Tehran University of Medical Sciences, Iran, 2 School of Clinical Dentistry, Shahed University, Tehran, Iran, 3 Faculty of Pharmacy, Tehran University of Medical Sciences, Iran Objectives: The purpose of this study was to evaluate the fracture resistance of a range of light-activated restorative materials by measurement of the plain strain fracture toughness (KIC) and “torque resistance to fracture” (T). Methods: Seventy-five notched disc test specimens from five light-activated restorative materials (n=15) of 5 mm diameter (±0.1 mm) and 2 mm depth (±0.1 mm) were prepared in a central notch (90° notch angle) PTFE mold. Materials evaluated were: A) Tetric Ceram (Ivoclar-Vivadent), fine-particle hybrid composite; B) Heliomolar (Ivoclar-Vivadent), microfilled composite; C) Spectrum TPH (Dentsply), sub-micron hybrid composite; D) Ideal Macoo (Ideal Macoo, Iran), hybrid composite; and E) Vitremer (3M ESPE), resin-modified glass ionomer restorative/core build up. Specimens were light-cured at zero distance for 60 s. The specimens were stored in distilled water at 37° C for 48 hrs. A cylindrical roller of 3 mm diameter was seated inside the V sections and fracture was accomplished in a universal testing machine with a two-point Mode I tensile load at a crosshead speed of 0.5 mm/min. Data was analysed by one way ANOVA and post-hoc paired Tukey test. Results: The mean KIC and torque to fracture (T) values for each material tested were: A) 3.08±0.42, 16.99±2.34; B) 1.91±0.32, 10.55±1.79; C) 3.40±0.53, 18.75±2.93; D) 2.87±0.46, 15.78±2.57; E) 0.61±0.19, 3.40±1.05 MN/m3/2±SD and N/mm±SD, respectively. Group E showed significantly the lowest mean KIC and (T) values among groups tested and then followed by Group B (P<0.01). The mean KIC and (T) values for Group C were significantly different from those of Groups B, D, and E (P<0.01) but not from those of Group A (P>0.05). Conclusions: Resin-modified glass ionomer restorative/core build up material (Vitremer, 3M ESPE) showed the lowest fracture resistance compared with the resin-based composite materials tested followed by the microfilled resin composite (Heliomolar, Ivoclar-Vivadent). | ||
| Seq #50 - Dental Materials: Physical Properties, Non - Polymers 2:00 PM-3:30 PM, Saturday, 28 August 2004 Crowne Plaza Hotel SEDIR III | ||
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