Improving the mechanical properties of glass-ionomer cement and composite resin restorative materials are desirable. In this study, glass fibers was incorporated into conventional glass-ionomer and light-cured composite resin restorative materials in 3 and 5 wt. percent. The tested mechanical properties were diametral tensile strength, hardness, flexural strength, flexural modulus and fracture toughness after 24 hours and 7 days of storage in deionized water.
Medifill, conventional glass ionomer and alphadent, light-cured composite resin restorative materials were used. Glass short fibers of 10μm thickness and 1 mm in length were treated with silane coupling agent and thoroughly mixed into the composite resin paste, whereas the glass ionomer powder was mixed with glass fiber without coupling agent. Samples of specific dimensions were prepared from each aterial for each time interval and concentration of glass fibers according to the manufacturer's instructions and ADA Specifications No 27. The hardness was measured using a micro hardness tester at 100 g applied load for 15 seconds. The other mechanical properties were measured using Lloyd universal testing machine.
the results obtained showed significant improvement of the mechanical properties for glass ionomer restorative material in both time intervals. Also, the properties studied were increased by increasing the fiber concentration On the other hand, light-cured composite resin showed increased diametral tensile strength and fracture toughness whereas, the other properties were not improved. Also, no steady improvement in these properties by increasing the fiber concentration or with longer storage time.
The results of this study suggest that, glass fiber-reinforced composite may restrict their use where high rigidity is required. Glass ionomer reinforced with glass fibers exhibited improved mechanical properties either with increasing the fiber concentration or storage time.
