Bone implants must simultaneous satisfy many requirements, even though the surface properties remain a crucial aspect to osseointegration success. Since a single material with a uniform structure cannot satisfy all these requirements, composite materials specifically designed to orthopaedic or dental implant application should be envisaged. Two poly(methyl-methacrylate)/hydroxyapatite composite reinforced by E-glass fibres, uncoated (PMMA/HA/Glass) and poly(2-hydroxyethyl methacrylate) (PMMA/HA/Glass+pHEMA) coated, were mechanically (pust-out test) and histomorphometrically (Affinity Index, AI) investigated in an in vivo rabbit model. Cylindrical implants were inserted into rabbit femoral cortical (middhiaphysis) and cancellous (distal epiphysis) bone, under general anaesthesia. The highest values of push-out force and ultimate shear strength were observed for the PMMA/HA/Glass at 12 weeks, which significantly differed from those of PMMA/HA/Glass+pHEMA at the same experimental time and from those of PMMA/HA/Glass at 4 weeks. At both experimental times, significant lower values of AI were observed in the PMMA/HA/Glass+pHEMA versus PMMA/HA/Glass (distal femoral epiphysis: 4 weeks= 33%; 12 weeks= 19%; femoral diaphysis: 4 weeks=15%; 12weeks=11%). The obtained good mechanical and histomorphometric results with PMMA/HA/Glass should be followed by further evaluation of bone remodeling process and mechanical strength around loaded PMMA/HA/Glass implants at longer experimental times. Finally, the biomimetic method applied on pHEMA needs to be furtherly investigated in order to improve the positive effect of SBF on pHEMA and to enhance the coating adhesion.
Poly(2hydroxyethyl methacrylate) biomimetic coating to improve osseointegration of a PMMA/HA/Glass composite implant: In vivo mechanical and histomorphometric assessments
Ambrosio L;
2004
Abstract
Bone implants must simultaneous satisfy many requirements, even though the surface properties remain a crucial aspect to osseointegration success. Since a single material with a uniform structure cannot satisfy all these requirements, composite materials specifically designed to orthopaedic or dental implant application should be envisaged. Two poly(methyl-methacrylate)/hydroxyapatite composite reinforced by E-glass fibres, uncoated (PMMA/HA/Glass) and poly(2-hydroxyethyl methacrylate) (PMMA/HA/Glass+pHEMA) coated, were mechanically (pust-out test) and histomorphometrically (Affinity Index, AI) investigated in an in vivo rabbit model. Cylindrical implants were inserted into rabbit femoral cortical (middhiaphysis) and cancellous (distal epiphysis) bone, under general anaesthesia. The highest values of push-out force and ultimate shear strength were observed for the PMMA/HA/Glass at 12 weeks, which significantly differed from those of PMMA/HA/Glass+pHEMA at the same experimental time and from those of PMMA/HA/Glass at 4 weeks. At both experimental times, significant lower values of AI were observed in the PMMA/HA/Glass+pHEMA versus PMMA/HA/Glass (distal femoral epiphysis: 4 weeks= 33%; 12 weeks= 19%; femoral diaphysis: 4 weeks=15%; 12weeks=11%). The obtained good mechanical and histomorphometric results with PMMA/HA/Glass should be followed by further evaluation of bone remodeling process and mechanical strength around loaded PMMA/HA/Glass implants at longer experimental times. Finally, the biomimetic method applied on pHEMA needs to be furtherly investigated in order to improve the positive effect of SBF on pHEMA and to enhance the coating adhesion.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
