Flexural behaviour of post-cured composites at oral-simulating temperatures.
Post-curing treatments have been known to improve the mechanical stability of visible light-cured composites. After individual post-curing treatment, the flexural strength (FS) of four commercial direct/indirect placement composite materials which differ greatly in composition [oligocarbonate dimethacrylate (OCDMA)-based Conquest C & B (CQT), Bisphenol-A glycidyl dimethacrylate (BisGMA)-based Charisma, urethane dimethacrylate (UDMA)-based Concept (CCT), and BisGMA/UDMA-based Dentacolor] was evaluated under water in the temperature range of 12-50 degrees C. A control series was tested in air at room temperature (25 +/- 1 degrees C). Data were analysed using ANOVA and Duncan's test. Flexural strengths overall decreased (20-40%, P < 0.01) with increasing temperatures except with Conquest C & B. Surprisingly, higher FS values were found in wet conditions than in dry conditions at 25 degrees C. UDMA-based materials much more easily undergo softening in water and by temperature change than do BisGMA- or OCDMA-based materials. Post-cured composites can be significantly affected by exposure to oral environments. Different composition determines the degree of influence.
Ho
C T
CT
Dental Department of Chang-Gung Memorial Hospital, Taipei, Taiwan, ROC.
Vijayaraghavan
T V
TV
Lee
S Y
SY
Tsai
A
A
Huang
H M
HM
Pan
L C
LC
D003188:Composite Resins / Q000737:chemistry*; D019245:Compressive Strength; D004548:Elasticity; D008027:Light; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D010316:Particle Size; D018583:Pliability; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D018709:Statistics, Nonparametric; D013674:Technology, Dental; D013696:Temperature; D013718:Tensile Strength
C084111:Charisma composite resin; D003188:Composite Resins; C069352:Concept resin; C092421:Conquest composite resin; D008689:Methacrylates; D019279:Resin Cements; D012821:Silanes; C057365:Dentacolor