The effect of three different calcium phosphate implant coatings on bone deposition and coating resorption: a long-term histological study in sheep.
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.
Schopper
Christian
C
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
Moser
Doris
D
Goriwoda
Walter
W
Ziya-Ghazvini
Farzad
F
Spassova
Else
E
Lagogiannis
Georgios
G
Auterith
Alexandra
A
Ewers
Rolf
R
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
D018786:Bone Substitutes; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D015921:Dental Implants; D005782:Gels; D017886:Durapatite; C018392:tricalcium phosphate