Bone Healing Performance of Electrophoretically Deposited Apatite-wollastonite/chitosan Coating on Titanium Implants in Rabbit Tibiae

Bone healing of tibial defect in rabbit model was used to evaluate a composite coating of apatite-wollastonite/chitosan on titanium implant. This coating has been developed to overcome the shortcomings, such as implant loosening and lack of adherence, of uncoated titanium implant. An electrophoretic deposition technique was used to coat apatite-wollastonite/chitosan on titanium implants. The present study was designed to evaluate the bone response of coated as compared to uncoated titanium implants in an animal model. After an implantation period of 14 (group A), 21 (group B), 35 (group C) and 42 days (group D), the bone-implant interfaces and defect site healing was evaluated using radiography, scintigraphy, histopathology, fluorescence labeling and haematology. Radiography of defect sites treated with coated implants suggested expedited healing. Scintigraphy of coated implant sites indicated faster bone metabolism than uncoated implant sites. Histopathological examination and fluorescence labeling of bone from coated implant sites revealed higher osteoblastic activity and faster mineralization. Faster bone healing in the case of coated implant sites is attributed to higher cell adhesion on electrostatically charged chitosan surfaces and apatite-wollastonite-assisted mineralization at bone-implant interfaces. Haematological studies showed no significant differences in haemoglobin, total erythrocyte and leukocyte counts, done using one way-ANOVA, during the entire study period. Our results show that AW/chitosan-coated implants have the advantages of faster bone healing, increased mechanical strength and good bone-implant bonding.