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Compounds that had neither calcined nor sintered hydroxyapatite (u-HA) particles (particulate size 0.2-20 microns, averaging 3.0 microns, Ca/P = 1.69, and containing CO3(2-) uniformly distributed in a poly-L-lactide (PLLA, Mv: 400 KDa) matrix with a content of 20-50 wt% (with 10% increment) were reinforced into composites by a forging process, which was a(More)
Ultra-high-strength poly(L-lactide) (PLLA) rods were fabricated using a drawing technique. Rods with a diameter of 3.2 mm and a draw ratio of 2.5:1 showed initial bending strength and modulus values of 240 MPa and 13 GPa, respectively. The purpose of this study was to investigate the in vitro and in vivo degradation of PLLA rods with a draw ratio of 2.5:1.(More)
The purpose of this study was to evaluate a biodegradable poly(L-lactide) (P-L-LA) screw for osteosynthesis under a load-bearing condition. A proximal tibial osteotomy on 25 rabbits was fixed with a biodegradable screw made of P-L-LA. A follow-up study was done at 1, 2, 4, 8, and 16 weeks. In another 25 rabbits, the tibial osteotomy was fixed with(More)
Bioabsorbable ultra high strength poly (L-lactide) rods, which were developed for internal fixation of fractures, were fabricated using a drawing technique. These rods were implanted in the subcutaneous tissue and in the medullary cavity of rabbits to investigate tissue reactions to poly (L-lactide) and to study their degradation process. After 18 months,(More)
STUDY DESIGN A new artificial intervertebral disc was developed, and its intrinsic biomechanical properties, bioactivity, and the effectiveness as a total disc replacement were evaluated in vitro and in vivo. OBJECTIVES To introduce a new artificial intervertebral disc and to evaluate the in vitro mechanical properties, fusion capacity to bone, and(More)
The in vitro multidirectional flexibility analysis was conducted to investigate the initial biomechanical effect of biomimetic artificial intervertebral disc replacement from either anterior or posterior approach in a cadaveric lumbosacral spine model. Two designs of anterior total and posterior subtotal artificial discs were developed using bioactive(More)
Miniscrews and miniplates made of forged composites composed of raw hydroxyapatite (u-HA) particles (particle size 0.2-20 microm, averaging 3.0 microm, Ca/p = 1.69 and containing CO3(2-)) and a poly L-lactide (PLLA, Mv: about 180 kDa, containing residual 0.05 wt% lactide) with osteological bioactivity such as direct bonding to bone and osteoconductivity,(More)
Here we document the complete process of bioresorption and bone replacement of rods made of forged composites of unsintered hydroxyapatite particles/poly l-lactide (F-u-HA/PLLA) implanted in the femoral medullary cavities of rabbits. Bioresorption, osteoconductive bioactivity and bone replacement were compared in three implantation sites. In the first site,(More)
The purpose of this study was to investigate the bone-implant interface of high-strength hydroxyapatite (HA)/poly(L-lactide) (PLLA) composite rods. As reinforcing particles, two types of HA particles-calcined HA (c-HA) and uncalcined HA (u-HA)-were applied to allow comparison of their suitability as bioactive fillers. Four types of composites (c-HA30,(More)
Unsintered hydroxyapatite particles/poly(L-lactide) (u-HA/PLLA) composites with an initial bending strength of up to 270 MPa were developed based on the hypothesis that inclusion of u-HA particles in a PLLA matrix might enhance bone bonding. The purpose of this study was to examine the bonding strength and behavior of these u-HA/PLLA composites on the(More)