The aims of this study were (1) to determine at the crystal level, the nonspecific biological fate of different types of calcium phosphate (Ca-P) ceramics after implantation in various sites (osseous and nonosseous) in animals and (2) to investigate the crystallographic association of newly formed apatitic crystals with the Ca-P ceramics. Noncommercial Ca-P ceramics identified by X-ray diffraction as calcium hydroxylapatite (HA), beta-tricalcium phosphate (beta-TCP), and biphasic calcium phosphates (BCP) (consisting of beta-TCP/HA = 40/60) were implanted under the skin in connective tissue, in femoral lamellar cortical bone, articular spine bone, and cortical mandibular and mastoidal bones of animals (mice, rabbits, beagle dogs) for 3 weeks to 11 months. In humans, HA or beta-TCP granules were used to fill periodontal pockets, and biopsies of the implanted materials were recovered after 2 and 12 months.(ABSTRACT TRUNCATED AT 250 WORDS)