Soft tissue responses to hydroxylapatite particles of different shapes.

Fifteen beagle dogs seven to 15 months of age had 0.5 g of hydroxylapatite in the form of sharp-edged particles (HA-1) or rounded particles (HA-2) implanted in buccal soft tissue pouches. Tissue specimens from each site were obtained at two weeks, six weeks, three months, and six months. A mild inflammatory response was seen at the implant sites with both particle shapes; however, inflammation resolved at a faster rate in the sites implanted with round hydroxylapatite particles.