Contributions on the study of the compressive strength of the light-cured composite resins.
The mechanical properties of the light-cured composite resins are related to the material composition, but also vary according to the light-source characteristics used for polymerization. In this study we followed the compressive strength variation for a light-cured composite resin according to the time of exposure to the curing light. With that end in view,18 test pieces were made from a light-cured hybrid composite material (Filtek Z250). The test pieces where then submitted to a compressive force by a mechanical properties universal testing machine. Our results didn't show an increase of the compressive strength according to the light-curing time increasing, than only in the light-curing time limit indicated by the manufacturer. A longer light-curing time may induce a shrinkage polymerization growth with the formation of internal tensions inside the material. The composite materials light-curing in short layers as long as there is indicated by the manufacturer seems to be a safer method to make the best from a resin qualities, then an exaggerated increase of the light-curing time. The light-curing is indicated to be done in the direction of the compressive forces. To confirm this supposition other mechanical tests are also necessary.
Department of Morphology and Semiology of Stomatognate System, Dental Materials and Dental Prosthesis Technology , Faculty of Dentistry, UMF Craiova.
H
H
Manolea
Faculty of Electromechanics, University of Craiova.
Sonia
S
Degeratu
Department of Morphology and Semiology of Stomatognate System, Dental Materials and Dental Prosthesis Technology , Faculty of Dentistry, UMF Craiova.
V
V
Deva
Department of Morphology and Semiology of Stomatognate System, Dental Materials and Dental Prosthesis Technology , Faculty of Dentistry, UMF Craiova.
Evantia
E
Coles
Department of Morphology and Semiology of Stomatognate System, Dental Materials and Dental Prosthesis Technology , Faculty of Dentistry, UMF Craiova.
Emma
E
Draghici
composite resins; compressive strength; light-curing time