The purpose of this study is to investigate the bone ingrowth effect of porous hydroxyapatite(HA) impregnated bone cement(polymethylmethacrylate, PMMA) through the histologic and biomechanical analysis. For this study, HA and PMMA were mixed in
weight
ratio 0:100, 10:90, 30:70, tomake 0%, 10%, 30% mixture cylindrical rod shaped sample, sized about 4mm × 10mm. The halves of each sample as control were decalcified to make a comparative histologic and biomechanical analy-sis of bone ingrowth
effect of
HA impregnated PMMA.
The histologic and biomechanical analyses in vitro and vivo were undertaken to evaluate the bone lngrowth effect of HA impregnated PMMA in several aspects to make a comparative analysis of the interfacial shear strength and a histologic analysis
of
HA
impregnated PMMA in vivo.
The comparative analysis of interfacial shear strength using hydraulically controlled machine(INSTRON) in vitro and histologic examination of HA impregnated PMMA in vivo were undertaken using each HA exposed samples(by grinding off and removing
the
surface coated PMMA) and those processed by surface decalcification, which were harvested from both sides of distal femuls of rabbit at 6weeks atter implantation, respectively.
@ES The following results were obtained;
@EN 1) In histologic observation using the hard tissue sectioning method with Villaneuva bone stain, there was peri-implant new bone formation in HA impregnatcd PMMA and more remakable in 30% samples, but an osseointegration into the HA was
observed
only in 30% sample. And 10% and 30% samples decalcifying off the surface HA, peri-implant new bone formation was observed also and more remakable in 30%. But there was no definite difference of bone ingrowth related periimplant new bone formation
after
and before decalcification about each 10% and 30% samples.
2) The statistically si9gnificant increase of interfacial shear strength through push-out test was observed in 30% samples (p<0.05) but not in 10% samples (p>0.05), compared with 0% samples. But there was no significant difference of interfacial
shear
strength after and before decalcification about each 10% and 30% samples also(p>0.05).
In conclusion, HA impregnated PMMA couldn't provide the optimal environment for earlier and stronger ossointegration and bone ingrowth than the usual PMMA. This study demonstrated a contradiciting fact from the published results in with an
increase
in
interfacial shear strength hod been reported with bone mineral particle impregnated PMMA by bone ingrowth into particles. Therefore, the present study showed that futher experimental evaluation warranting the clinical application of bone mineral
particles impregnated bone cement should be considered.
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