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Biomedical subjects

C W Fairhurst

Publications and source records attributed to C W Fairhurst.

68 records · Page 4Linked to original sources
PubMedDate not supplied

New information on high copper amalgam corrosion.

Anodic polarization of "pure" Cu6Sn5 was investigated. Cu6Sn5 is found to be passive in nearly neutral synthetic saliva. Anodic corrosion activity (characteristic for tin) previously reported for a high copper amalgam must result from the presence of the gamma2 phase or tin in the matrix phase.

Chemical Phenomena↗
PubMedDate not supplied

Detecting silver-containing metal ceramic alloys that discolor porcelain.

Dental laboratories need an internal method to detect silver-containing metal ceramic alloys that stain porcelain. A fiberoptic colorimeter, calculations, and data describe Ag-vapor staining in standard CIE (1976) L*a*b* color space. The color difference value (CDV) of delta L*, delta a*, delta b*, and delta E* for porcelain before and after firing with Pd-Ag alloy, Au-Pt-Pd alloy, and control groups were calculated from L*, a*, and b* values. The CDV for all groups showed a more translucent (-delta L*) porcelain after the second firing. The CDV of porcelain disks exposed to Pd-Ag alloy showed an intense yellow (+ delta b*) stain with slight "greening" (-delta a*). The disks exposed to the Au-Pt-Pd group showed a slight yellow (-delta b*) stain. The delta b* values for the Pd-Ag group were significantly different from the other groups. This color shift (+ delta b) was clearly observed with the unaided eye.

Colorimetry↗
PubMedDate not supplied

Fatigue failure parameters of IPS-Empress porcelain.

The purpose of this study was to determine the stress corrosion fatigue characteristics of a heat-pressed ceramic material, IPS-Empress. Disks (1 mm thick, 12 mm in diameter) were prepared, polished, and subjected to dynamic loading at multiple constant stressing rates. Fatigue tests were conducted in a circulating bath using a biaxial flexure test. The inert strength of the samples was determined in oil. The mean fracture strength for the inert tests was 135.7 MPa. Linear regression analysis of log fracture strengths vs log time to failure was performed to obtain fatigue parameters. For IPS-Empress the n value was 31 (SE 3.5) and sigma f0 was 83.3 MPa (SE 1.3 MPa).

Aluminum Silicates↗
PubMedDate not supplied

Fatigue characteristics of a high-strength porcelain.

The purpose of this study was to determine stress corrosion fatigue characteristics of Optec-hsp porcelain. Disks (1 mm thick and 12 mm in diameter) were prepared according to the manufacturer's firing recommendations. Samples were subjected to dynamic loading at multiple constant stressing rates. Dynamic fatigue was measured using a biaxial flexural strength test in a circulating bath. Inert strength was determined in a moisture-free environment. The mean fracture strength for the dry (moisture-free) samples was 167.9 MPa. Linear regression analysis of log fracture strengths vs log time to failure was performed to obtain fatigue parameters. For Optec, the n-value was 26 (SE 1.9) and sigma f0 was 91.3 MPa (SE 1.2 MPa).

Chemical Phenomena↗