title: [Ultrasonic measurement of the elastic properties of goat condyles].
abstract: OBJECTIVE
  The purpose of this experiment is to investigate the elastic properties of goat mandibular condyles and to provide basic constants for biomechanical study of temporomandibular joint.
  
  
  METHODS
  A fresh goat mandible was adopted and the standard condyle specimen of 4 mm x 6 mm x 10 mm was obtained from it. The structure density of the condyle was determined according to Archimede's principle. The transmitting velocities of ultrasonic wave in different directions of goat condyles were measured by using the ultrasonic system, which was composed of a transmitting transducer of 1.25 MHz, a receiving transducer of 2.5 MHz, an ultrasonic analyzer (5052UA) and a digital storage oscilloscope (HP54601A). The elastic coefficients and technical constants could be calculated by elastic equations.
  
  
  RESULTS
  The structural density of the sample and the wave velocities in different directions of the condyle were both obtained by direct measurement. And then, nine elastic coefficients and all of the technical constants of orthotropic condyles were calculated.
  
  
  CONCLUSIONS
  1. It is practicable to measure elastic properties of the condyle by using ultrasonic technique. 2. Goat condyles of the mandible are a type of anisotropic and linearly elastic material. 3. The direction perpendicular to the transverse ridge of the goat condyle has the highest Young's modulus. As to shear modulus, the direction along the transverse ridge shows the highest value.
authors.affiliation: College of Stomatology, Fourth Military Medical University.
authors.forename: M
authors.initials: M
authors.lastname: Zhang
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: M
authors.initials: M
authors.lastname: Wang
authors.forename: Z
authors.initials: Z
authors.lastname: Shang
authors.forename: J
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density; D004548:Elasticity; D006041:Goats; D066298:In Vitro Techniques; D008335:Mandibular Condyle / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D012016:Reference Values; D014463:Ultrasonography