Histomorphometric Assessment of Implant Coating with A Mixture of Strontium Chloride and Hydroxyapatite at Different Concentration

Surface properties are one of the major keys of successful implant osseointegration in addition to mechanical strength and excellent biocompatibility of implant material. The purpose of this study is to make histological and histomorphometric analysis of an implant coated with strontium chloride (SrCl₂) mixed with hydroxyapatite (HA) at different concentrations, in rabbit tibia at 2 and 6 weeks of implantation time.

48 commercially pure titanium screw shaped implants were placed in 24 healthy adult New Zeeland rabbits, each rabbit received 2 implants; one coated with mixture 1 (25% HA and 75% SrCl₂) and the other coated with mixture 2 (75% HA and 25% SrCl₂). Twelve rabbits were sacrificed at 2 weeks of healing and other twelve after 6 weeks. The new bone area and number of cells (osteoblast and osteoclast) were assessed by light microscope.

Statistical analysis showed significant differences in new bone formation ratio after 2 weeks of healing and non-significant differences after 6 weeks of healing. Data also suggested that osteoblast was increased, and osteoclast was decreased in mixture 2 (75% HA and 25% SrCl₂) more than mixture 1 (25% HA and 75% SrCl₂).

There was a significantly higher new bone formation ratio of mix 2 (25%Sr-75%HA) coated Cp-Ti implants than mix 1 (75% Sr-25% HA) coated Cp-Ti implant at 2 weeks healing period, also there was an increase in new bone formation ratio with time for both coated materials (SrCl₂) implants.