Resin composite properties and energy density of light cure.
According to the "total energy concept", properties of light-cured resin composites are determined only by energy density because of reciprocity between power density and exposure duration. The kinetics of polymerization is complex, and it was hypothesized that degree of cure, flexural strength, and flexural modulus were influenced not only by energy density, but also by power density per se. A conventional resin composite was cured at 3 energy densities (4, 8, and 16 J/cm(2)) by 6 combinations of power density (50, 100, 200, 400, 800, and 1000 mW/cm(2)) and exposure durations. Degree of cure, flexural strength, and flexural modulus increased with increasing energy density. For each energy density, degree of cure decreased with increasing power density. Flexural strength and modulus showed a maximum at intermediate power density. Within clinically relevant power densities, not only energy density but also power density per se had significant influence on resin composite properties.
Department of Dental Materials, School of Dentistry, University of Copenhagen, 20 Nørre Allé, 2200 Copenhagen N, Denmark. apz@odont.ku.dk
A
A
Peutzfeldt
E
E
Asmussen
D000704:Analysis of Variance; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects*; D003764:Dental Materials / Q000737:chemistry / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D004735:Energy Transfer; D006244:Hardness / Q000528:radiation effects; D008027:Light; D008029:Lighting / Q000295:instrumentation; D008422:Materials Testing; D018709:Statistics, Nonparametric; D013997:Time Factors
D003188:Composite Resins; D003764:Dental Materials