title: Significance of peak value and duration of the interfacial shear load in evaluation of the bone-implant interface.
abstract: OBJECTIVE
  To determine if there is any merit in measuring peak load duration in studies of bone-implant interface during a pull-out test was performed to record the interfacial shear load.
  
  
  METHODS
  Mechanical and histological investigations were performed to determine the bone-implant interfacial strength.
  
  
  BACKGROUND
  A common long-term problem following artificial joint replacement is the formation of an intervening fibrous tissue seam at the interface between bone and a prosthesis. To investigate the nature and strength of interfacial attachment between bone and an implanted biomaterial, a detaching method such as pull-out test can be used.
  
  
  METHODS
  Four porous surfaced alumina ceramic implants with or without glass-ceramic containing apatite and wollastonite coating at the surface of the beads and the substrate were implanted into canine the femoral condyles. Peak value and its duration of the interfacial shear load for the different types of implants were analyzed. Tissue formed at the bone-implant interfaces were examined histologically.Results. The peak value of interfacial shear load of the apatite and wollastonite glass-ceramic-coated implant was significantly greater than that of the non-coated implant at every stage, but the peak value duration in the control at each time period was greater than that of the coated implant. Histologically, more bone tissue ingrowth in the pores of coated implants, whereas a gap was observed at the interface of bone and the non-coated implant.
  
  
  CONCLUSIONS
  The interfacial shear load values, peak and its duration, are significantly influenced by the direct bone bonding or the intervening fibrous tissue which formed at the bone-implant interface.
  
  
  CONCLUSIONS
  The peak load measurement and the duration of the peak load value are useful to measure the strength of interfacial attachment between bone and an implanted biomaterial. However, the duration of peak load value is closely related to the strength and plasticity of the tissue formed in the bone-implant interface. The analysis of peak value duration could be used to determine the properties of new grown tissue before histologic examination.
authors.affiliation: Institute for Frontier Medical Sciences, Kyoto University, Kyoto, 606, Japan. yongshunchang@texashealth.org
authors.forename: Yong-Shun
authors.initials: YS
authors.lastname: Chang
authors.forename: Masanori
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Zhong-Lian
authors.initials: ZL
authors.lastname: Li
authors.forename: Masanori
authors.initials: M
authors.lastname: Oka
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D018786:Bone Substitutes; D004285:Dogs; D019544:Equipment Failure Analysis / Q000379:methods*; D005269:Femur / Q000503:physiopathology* / Q000601:surgery / Q000648:ultrastructure*; D019736:Prostheses and Implants; D011475:Prosthesis Failure; D033081:Shear Strength; D013499:Surface Properties; D016474:Weight-Bearing
chemical_list: D018786:Bone Substitutes