Long-term effects of magnetron-sputtered calcium phosphate coating on osseointegration of dental implants in non-human primates.

Objectives: To determine the effect of magnetron-sputtered calcium phosphate coating of implants on the later stages of osseointegration in a non-human primate model.
Material and Methods: Eighteen and 20 implants with a 0.1 microm amorphous calcium phosphate coating and a turned surface, respectively, were inserted in the anterior upper and lower jaw of adult non-human primates. Following a 7.5 months healing period, one part of the implants remained in the submerged position. The other part of implants was connected to healing abutments to allow peri-implant inflammation to occur. After another 20 months, histologic and histomorphometric analysis of the peri-implant area was performed.
Results: Submerged implants with a calcium phosphate coating and a turned surface showed no signs of an inflammatory reaction. The histomorphometric parameters 'bone volume per tissue volume' (BV/TV) and 'bone-to-implant contacts' (BIC) were not affected by calcium phosphate coating. Non-submerged implants of both groups showed occasionally signs of inflammation at the implant-abutment junction. Histomorphometric analysis revealed that the distance between the implant-abutment junction and the most coronal level (where bone was attached to the implant) as well as BV/TV and BIC were independent from the surface modification.
Conclusion: Our results show that dental implants with calcium phosphate coating behave similar to turned implants independently whether they are connected to healing abutments or remain submerged. Ultra-thin calcium phosphate coating can combine the positive effects of calcium phosphate during the early stage of osseointegration without causing impairment of the later stages.