title: The effect of three different calcium phosphate implant coatings on bone deposition and coating resorption: a long-term histological study in sheep.
abstract: The present study investigated the hypothesis that hydroxyapatite (HA), tricalcium phosphate (TCP), and a HA-gel coated on endosseous titanium (Ti) implants by spark discharging (SD) and dip coating would achieve predictable osseointegration without evident bioresorption of the coatings on the long term. A costal sheep model was used for the implantation of the HA/SD, HA/TCP/SD, and HA-gel/SD specimens, which were retrieved 6 and 12 months following implantation. HA and Ti coatings on implants obtained by conventional plasma spraying (HA/PS, Ti/PS) were used as controls. Microscopy showed that osseointegration was achieved from all types of implants. No evidence for bioresorption of the HA/SD, HA/TCP/SD, and HA-gel/SD coatings was present but cohesive failure with disruption of the coating/implant interface was seen. A statistical analysis of the histomorphometrical data showed no time-dependent effect, however. HA/PS coatings achieved significantly higher bone-implant contact (BIC) percentages of the total implant surface (toBIC) than the other types of coatings (P=0.01). If the BIC percentages were traced separately for implant portions placed into cortical and cancellous bone (coBIC and caBIC, respectively), detailed analysis showed that the caBIC values of HA-gel/SD and HA/PS coatings were significantly higher than that of the other types of coatings (P=0.01). CaBIC values were highly correlated with toBIC values (P<0.001). The present study showed that the preparation techniques used produced thin, dense, and unresorbable coatings that achieved osseointegration. Compared with the control coatings, however, only HA-gel/SD coating can be recommended from the investigated preparation techniques for a future clinical use if a better coating cohesion is achieved.
authors.affiliation: University Hospital of Cranio-Maxillofacial and Oral Surgery, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria. mkg-forschung@akh-wien.ac.at
authors.forename: Christian
authors.initials: C
authors.lastname: Schopper
authors.forename: Doris
authors.initials: D
authors.lastname: Moser
authors.forename: Walter
authors.initials: W
authors.lastname: Goriwoda
authors.forename: Farzad
authors.initials: F
authors.lastname: Ziya-Ghazvini
authors.forename: Else
authors.initials: E
authors.lastname: Spassova
authors.forename: Georgios
authors.initials: G
authors.lastname: Lagogiannis
authors.forename: Alexandra
authors.initials: A
authors.lastname: Auterith
authors.forename: Rolf
authors.initials: R
authors.lastname: Ewers
mesh_terms: D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects* / Q000502:physiology; D018786:Bone Substitutes / Q000627:therapeutic use*; D002130:Calcium Phosphates / Q000627:therapeutic use*; D020099:Coated Materials, Biocompatible / Q000378:metabolism / Q000627:therapeutic use*; D015921:Dental Implants; D017886:Durapatite / Q000627:therapeutic use*; D005260:Female; D005782:Gels; D016348:Osseointegration / Q000187:drug effects; D012756:Sheep
chemical_list: D018786:Bone Substitutes; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D015921:Dental Implants; D005782:Gels; D017886:Durapatite; C018392:tricalcium phosphate