الفهرس 
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Abstract
Ceramic implants have been proposed as an alternative to titanium implants, based principally on their esthetic and superior biocompatibility. Chemical and physical characterizations of implant surface are important factors that affect the osseointegration process. However, improvement of implant-bone integration can be achieved by implant surface modification.
Hydroxyapatite (HA) coatings have been applied to implant fixtures to produce a bioactive surface that presumably promotes and achieves direct bond between the implant and the hard tissue. Also, the biological acceptance and functional of dental implants might be improved by modifying their surfaces with extra cellular matrix (ECM) components.
The aim of this work was to evaluate the influence of three different bioactive coats that absorbed into nano-porous surfaces of zirconia implants on peri-implant bone healing and osseointegration in rabbits. These three different bioactive coats were: [i] Extracted natural hydroxyapatite, [ii] Commercial hydroxyapatite (Bio-Oss), and [iii] Platelet rich plasma (PRP).
This work was performed through a research design including laboratory and experimental studies. Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) zirconia blocks were used for the preparation of zirconia discs (19mm×3mm) and implants (3.7mm×8mm). Then all zirconia specimens were subjected to selective infiltration etching technique (SIE) to modify their dense and smooth (non-bonding) surfaces into nano-porous (highly retentive) surfaces that could be able to absorb the applied bioactive coats. These nano-porous zirconia surfaces were characterized before the coating procedures with porosity test and scanning electron microscopy (SEM).
Pure natural HA was extracted from the femurs of the same animals of the experimental study (Line V Spain white rabbits), then it was characterized for its chemical structure and crystal phase purity with energy dispersive X-ray analysis (EDX) and X-ray diffraction analysis (XRD), respectively. Also, the commercial HA (Bio-Oss) was characterized with the same previously mentioned tests, to be compared with the extracted natural HA.