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Updated: Jul 21, 2026
An Improved Mechanical Testing Method to Assess Bone-implant Anchorage
Published on: February 10, 2014
In vivo evaluation of hydroxyapatite coatings of different crystallinities
Sunho Oh1, Eric Tobin, Yunzhi Yang
1University of Tennessee Health Science Center, Department of Biomedical Engineering, Memphis, TN 38163, USA.
Purpose:
The influence of calcium phosphate (CaP) and hydroxyapatite (HA) crystallinity on bone-implant osseointegration is not well established. In this study, the effect of HA crystallinity and coating method on bone-implant osseointegration was investigated using a rat tibia model.
Materials And Methods:
HA coatings 1 to 5 microm thick were produced using a supersonic particle acceleration (SPA) technology. The HA crystallinities used for this study were weight ratios of 30%, 50%, 70%, and 90%. A total of 128 HA-coated implants were placed into the tibiae of 64 male Sprague-Dawley rats. Bone-implant interfaces were evaluated using histology and push-out strength testing at 3 and 9 weeks after implantation.
Results:
The 70% crystalline coatings exhibited significantly greater interfacial strength (5 implants/time point/treatment) than the 30%, 50%, and 90% crystalline coatings at 3 and 9 weeks following implantation. The implants with coatings of 70% crystallinity also had the greatest bone contact length. In addition, the HA coatings produced with SPA demonstrated greater interfacial strength and bone contact length than plasma-sprayed HA coatings (except for the HA coating with 30% crystallinity).
Discussion:
HA coatings of different crystallinities exhibited different dissolution and re-precipitation properties which may enhance early bone formation and bone bonding.
Conclusions:
This study suggested that coating crystallinity and coating methods can influence the bone-implant interface.
