title: Effect of light curing method on volumetric polymerization shrinkage of resin composites.
abstract: Volumetric polymerization shrinkage of three resin composites (Suprafil, Z100 and Filtek P60) was determined using four light curing methods: method 1: continuous output with conventional intensity light; method 2: continuous output with higher intensity light; method 3: ramp output and method 4: pulse-delay output. Five disc-shaped specimens were prepared from each material for each curing method. Specimen weight was determined with an analytical electronic hydrostatic balance in air and in water before and after curing. Specific gravity values were then determined. Volumetric polymerization shrinkage was calculated using mathematical formulas. Mean volumetric polymerization shrinkage ranged from 1.882 (.015)% to 2.169 (.028)%. ANOVA indicated significant differences among the materials (p<.05). Light curing methods had no effect on volumetric polymerization shrinkage except for Z-100, where method 2 resulted in significantly higher shrinkage than methods 1 and 4. Suprafil shrunk significantly less than the other two materials in all curing methods.
authors.affiliation: Department of Operative Dentistry, University of Bahia, School of Dentistry, Salvador, BA, Brazil.
authors.forename: M J M
authors.initials: MJ
authors.lastname: Coelho Santos
authors.forename: G C
authors.initials: GC
authors.lastname: Santos
authors.forename: H
authors.initials: H
authors.lastname: Nagem Filho
authors.forename: R F L
authors.initials: RF
authors.lastname: Mondelli
authors.forename: O
authors.initials: O
authors.lastname: El-Mowafy
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects*; D003748:Dental Equipment; D018772:Dental Marginal Adaptation; D003799:Dental Stress Analysis; D008027:Light; D008422:Materials Testing; D015394:Molecular Structure; D044367:Phase Transition; D011108:Polymers / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry / Q000528:radiation effects; D018709:Statistics, Nonparametric; D015040:Zirconium / Q000737:chemistry / Q000528:radiation effects
chemical_list: D003188:Composite Resins; C438835:Filtek P60 Composite Resin; D011108:Polymers; C485361:Suprafil; C083568:Z100 composite resin; D012822:Silicon Dioxide; D015040:Zirconium