hrvatski

Mechanical properties of dual-cure resin cements after artificial aging

Introduction: To evaluate flexural strength (FS) and flexural modulus (FM) of dual-cure resin cements polymerized using different curing protocols. Materials and methods: Four dual-cure cements and one light-cure cement were investigated. The specimens for the three-point bending test (2x2x16 mm) were prepared using the following three curing protocols: (I) 1200 mW/cm2 for 10 s immediately adjacent to the specimen surface, (II) 1200 mW/cm2 for 20 s through a 1-mm layer of disilicate ceramics, and (III) without light illumination. The specimens were artificially aged using 30-day immersion in water followed by 7-day immersion in absolute ethanol. Mechanical testing was performed in a universal testing machine at a crosshead speed of 1 mm/ min until fracture. Results: The investigated materials demonstrated a wide range of FS (11.4– 111.1 MPa) and FM (0.65–5.5 GPa). FS and FM values were notably material-dependent and significantly affected by curing protocols in all tested materials. The self-curing protocol resulted in up to 25% poorer mechanical properties compared to the corresponding maximum values attained by the maximum light exposure provided by curing protocol (I). In addition to being significantly affected by curing protocols, mechanical properties of the lightcure resin cement were at the low-end of all investigated materials. For all materials, FM was more affected by different curing protocols than FS. Conclusions: The dual-cure resin composite cements should be additionally light-cured in order to attain optimal mechanical properties. Also, direct exposure to the curing light resulted in improved mechanical properties compared to the light exposure through a 1-mm thick ceramic layer.

flexural strength ; flexural modulus ; dual-curing cements ; resin cements

nije evidentirano

engleski

Mechanical properties of dual-cure resin cements after artificial aging

Introduction: To evaluate flexural strength (FS) and flexural modulus (FM) of dual-cure resin cements polymerized using different curing protocols. Materials and methods: Four dual-cure cements and one light-cure cement were investigated. The specimens for the three-point bending test (2x2x16 mm) were prepared using the following three curing protocols: (I) 1200 mW/cm2 for 10 s immediately adjacent to the specimen surface, (II) 1200 mW/cm2 for 20 s through a 1-mm layer of disilicate ceramics, and (III) without light illumination. The specimens were artificially aged using 30-day immersion in water followed by 7-day immersion in absolute ethanol. Mechanical testing was performed in a universal testing machine at a crosshead speed of 1 mm/ min until fracture. Results: The investigated materials demonstrated a wide range of FS (11.4– 111.1 MPa) and FM (0.65–5.5 GPa). FS and FM values were notably material-dependent and significantly affected by curing protocols in all tested materials. The self-curing protocol resulted in up to 25% poorer mechanical properties compared to the corresponding maximum values attained by the maximum light exposure provided by curing protocol (I). In addition to being significantly affected by curing protocols, mechanical properties of the lightcure resin cement were at the low-end of all investigated materials. For all materials, FM was more affected by different curing protocols than FS. Conclusions: The dual-cure resin composite cements should be additionally light-cured in order to attain optimal mechanical properties. Also, direct exposure to the curing light resulted in improved mechanical properties compared to the light exposure through a 1-mm thick ceramic layer.

flexural strength ; flexural modulus ; dual-curing cements ; resin cements

nije evidentirano