Cyclic loading of notched dental composite specimens
Received 21 September 2009; accepted 4 October 2009.
Abstract
Objective
The purpose of this study was to examine the fracture toughness (KIC) of three direct dental composites and one indirect dental composite subject to cyclic loading.
Methods
The composites were a micro-filled (Micronew, Bisco INC., Schaumburg, IL, USA), a hybrid (Renew, Bisco INC.), a nano-filled composite (Filtek Supreme Plus, 3M ESPE, St. Paul, MN, USA) and an indirect dental composite (BelleGlass HP, SDS-Kerr, Orange, CA, USA). Rectangular bar specimens (3mm×3mm×25mm) were fabricated, notched, aged (5 months) and cyclic loaded in four different environments, air, water, artificial saliva, and a 50/50 by volume mixture of ethanol and water. Specimens were cyclic loaded for 1, 1000, 10,000, and 100,000 cycles.
Results
A 3-way ANOVA (non-aged and aged group, four aging media, four loading cycles) showed a significant difference between non-aged and aged, aging media, and loading cycles. For the control groups as the number of cycles increased, there were no significant differences on the number of cycles completed and fracture toughness, except for Micronew, which showed an increased specimen failure rate and decreased fracture toughness. In the aged groups, cyclic loading in water and artificial saliva did not have a significant effect on BelleGlass HP, Filtek Supreme Plus and Renew for fracture toughness and the number of cycles completed, However for Renew in the 50/50 mixture at 100,000 cycles, Filtek Supreme Plus in air and the 50/50 mixture, and Micronew, there was an increased specimen failure rate and a decreased fracture toughness during cyclic fatigue loading as the number of cycles increased.
Significance
BelleGlass HP displayed the best overall resistance to cyclic loading, followed by Renew and Filtek Supreme Plus, and Micronew.
Department of Restorative Dentistry, University of Illinois at Chicago, Chicago, IL, USA
Corresponding author. Department of Restorative Dentistry m/c 555, University of Illinois at Chicago, 350 College of Dentistry, 801 South Paulina Street, Chicago, IL 60612-7212, USA. Tel.: +1 312 996 2669; fax: +1 312 996 3535.
ABSTRACT