title: Shear modulus--measurement methodology with application to light-cured resin composites.
abstract: OBJECTIVE
  This study was conducted to test a novel methodology for shear modulus determination of light-cured resin composites.
  
  
  METHODS
  Using a butterfly-shaped specimen, a special loading device was able to apply pure uniform shear stress on a significant region of the specimen. Validation of the method was proven by photoelastic experiments. Shear modulus was directly obtained through shear stress-strain curve where the strains were measured by a shear strain gauge rosette. The composite materials analyzed were one microfill (Silux Plus, 3M Dental Products) and four hybrids (Brilliant, Coltene; Herculite XRV, Kerr; Z-100, 3M Dental Products; Graft LC, GC). An analysis of variance was used to evaluate the G modulus (p<0.01).
  
  
  RESULTS
  Modulus values varied between 2.54-8.01 GPa. The microfilled material presented the lowest value, and Graft LC presented the highest value. A statistically significant difference was found between all materials (p<0.01).
  
  
  CONCLUSIONS
  The described methodology can also be applied to other restorative materials, as well as to adhesion strength measurements.
authors.affiliation: Section of Oral Rehabilitation, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel.
authors.forename: T
authors.initials: T
authors.lastname: Brosh
authors.forename: R
authors.initials: R
authors.lastname: Pilo
authors.forename: M
authors.initials: M
authors.lastname: Arcan
mesh_terms: D000704:Analysis of Variance; D001718:Birefringence; D003188:Composite Resins / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation / Q000379:methods*; D004548:Elasticity; D008027:Light; D008422:Materials Testing / Q000295:instrumentation / Q000379:methods*; D019279:Resin Cements; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D015040:Zirconium / Q000737:chemistry
chemical_list: C075707:Brilliant Enamel; D003188:Composite Resins; D019279:Resin Cements; C083568:Z100 composite resin; C065770:Herculite XR; C074741:Silux Plus; C073856:Graft LC; D012822:Silicon Dioxide; D015040:Zirconium