Effects of Whisker-to-silica Ratio on the Reinforcement of Dental Resin Composites with Silica-Fused Whiskers

Published

January 1, 2000

Author(s)

Hockin D. Xu, Janet Quinn, Anthony A. Giuseppetti, F Eichmiller

Abstract

Resin composites need to be strengthened to improve their performance in large stress-bearing restorations, crowns, and multiple-unit applications. This study aimed to reinforce composites with silica-fused silicon carbide whiskers, and to investigate the effects of whisker:silica ratio and filler level. Silica particles and whiskers were mixed at seven whisker:silica mass ratios: 1:0, 5:1, 2:1, 1:1, 1:2, 1:5, and 0:1. Each mixture was heated at 800 EC for 30 min to fuse the silica particles onto the whiskers. Each heated mixture was silanized and combined with a dental resin at filler level mass fractions ranging from 0 % to 65 %. The resulting composites were molded and heat-cured at 140 EC for 30 min. Flexural strength and work-of-fracture were measured from transverse bars, and specimen fracture surfaces were examined with SEM. Two laboratory-processed prosthetic composites were used as comparative controls. Whisker:silica ratio and filler level had significant effects on composite properties. At 60 % filler level, the silica composite (whisker:silica = 0:1) had a flexural strength (mean SD; n = 6) of (104 21) MPa; that of the whisker composite (whisker:silica = 1:0) was (74 36) MPa. However, that of the silica-fused whisker composite (whisker:silica = 5:1) was (210 14) MPa, compared to (109 23) MPa and (114 18) MPa of the two prosthetic controls. The work-of-fracture value of the silica-fused whisker composite at whisker:silica = 5:1 was also nearly two times those of the controls. These results, coupled with SEM examinations, indicate that fusing silica particles onto whiskers facilitated silanization, minimized whisker entanglement, improved filler distribution in the matrix, and roughened whisker surfaces to enhance retention in the matrix.

Citation

Journal of Dental Research

Volume

79

Issue

No. 11

Pub Type

Journals

Keywords

filler level, reinforcement mechanisms, resin composite, strength, whisker-to-silica ratio

Citation

Xu, H. , Quinn, J. , Giuseppetti, A. and Eichmiller, F. (2000), Effects of Whisker-to-silica Ratio on the Reinforcement of Dental Resin Composites with Silica-Fused Whiskers, Journal of Dental Research (Accessed April 19, 2024)