A resonance frequency technique was applied to determine the elastic modulus of hydroxyapatite. A Free-Free Vibration Transducer was designed to determine elastic modulus in a longitudinal direction. A Fixed-Free Vibration Transducer was also designed to study elastic modulus of materials were specimens longer than 3 cm in length were not available. Six lots of hydroxyapatite were prepared utilizing the same process. The elastic modulus of hydroxyapatite varied between 3.94 x 10(10) (dyn/cm2) and 6.30 x 10(10) (dyn/cm2) in a longitudinal direction. For the same six lots, it varied between 1.95 x 10(10) (dyn/cm2) and 3.20 x 10(10) (dyn/cm2) in a cross direction. The elastic modulus values of cortical bone from dog tibias, fibulas, and femurs were also determined.
The statistical theory of strength was used to obtain tensile strength distribution curves of dental restorative specimens of differing volumes. The most probable tensile strength of Adaptic*† dental restorative material increased with a decrease in specimen volume within practical limits. The tensile strength distribution curves were unsymmetrical.
Rheological properties of aged specimens of four restorative materials were investigated at 37 C by a nondestructive test method using an acoustic spectrometer. An amalgam was found to have the highest Young's modulus and lowest dynamic viscosity. A Poisson's ratio of about 0.2 was obtained for all of the dental restoratives.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.