title: Dynamic viscoelastic properties of commercial glass-fibre reinforced resin used for crowns and bridges.
abstract: In order to investigate the thermal stability, the physical and mechanical, and dynamic viscoelastic properties of glass-fibre reinforced composite materials were measured. The G' of the seven materials examined was within 5;20 +/- 14; 55 and 4;50-14; 35 GPa for dry and wet specimens in air at 37 degrees C, respectively, and decreased with increasing temperature. The G' values of dry specimens decreased by 7;74-15;4% when heated to 60 degrees C. The value of tan delta ranged from 0;0102 to 0;0295 and from 0.0181 to 0.0406 for dry and wet specimens in air at 37 degrees C, respectively. The coefficient of linear thermal expansion between 30 and 60 degrees C ranged from 0;557 to 3; 95 x 10-5/ degrees C. Moreover, the filler content ranged from 56; 36 to 88; 87 wt%. These results showed that the magnitudes of G', tan delta, and the coefficient of linear thermal expansion and water absorption depend on the inorganic filler or glass-fibre content; i.e. the amount of resin matrix. Moreover, for all the materials examined, the G' values were thermostable in the temperature range encountered in the oral cavity.
mesh_terms: D000042:Absorption; D003188:Composite Resins / Q000737:chemistry*; D003442:Crowns; D003799:Dental Stress Analysis; D003830:Denture, Partial, Fixed; D004055:Differential Thermal Analysis; D004548:Elasticity; D005898:Glass; D008422:Materials Testing; D010316:Particle Size; D033081:Shear Strength; D014783:Viscosity; D014867:Water
chemical_list: D003188:Composite Resins; C009753:fiberglass; D014867:Water