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Whisker-Reinforced Dental Core Buildup Composites: Effect of Filler Level on Mechanical Properties



Hockin D. Xu, Douglas T. Smith, Gary E. Schumacher, F Eichmiller


The strength and toughness of dental corebuildup composites in large stress-bearing restorations need to be improved to reduce the incidence of fracture due to stresses from chewing and clenching. The aims of the present study were to develop novel core buildup composites reinforced with ceramic whiskers, to examine the effect of filler level, and to investigate the reinforcement mechanisms. Silica particles were fused onto the whiskers to facilitate silanization and to roughen the whisker surface for improved retention in the matrix. Filler level was varied from 0 to 70%. Flexural strength, compressive strength, and fracture toughness of the composites were measured. A nano-indentation system was used to measure elastic modulus and hardness. Scanning electron microscopy (SEM) was used to examine the fracture surfaces of specimens. Whisker filler level had significant effects on composite properties. The flexural strength in MPa (mean SD; n = 6) increased from (95 15) for the unfilled resin to (193 8 for the composite with 50% filler level, then slightly decreased to(176 12) at 70% filler level. The compressive strength increased from (149 33) for the unfilled resin to (282 48) at 10% filler level, and remained equivalent from 10 to 70%filler level. Both the modulus and hardness increased monotonically with filler level. In conclusion, silica particle-fused ceramic single-crystaline whiskers significantly reinforced dental core buildup composites. The reinforcement mechanisms appeared to be crack deflection and bridging by the whiskers. Whisker filler level had significant effects on theflexural strength, compressive strength, elastic modulus,and hardness of composites.
Journal of Biomedical Materials Research
No. 4


ceramic whisker reinforcement, core buildup, dental composites, filler level, indentation, modulus, strength, toughness


Xu, H. , Smith, D. , Schumacher, G. and Eichmiller, F. (2000), Whisker-Reinforced Dental Core Buildup Composites: Effect of Filler Level on Mechanical Properties, Journal of Biomedical Materials Research (Accessed July 18, 2024)


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Created December 1, 2000, Updated February 17, 2017