This study evaluated the use of tricalcium phosphate (TCP) ceramic implant material in periodontal osseous defects. Thirteen defects in two patients were treated with mucoperiosteal flaps and placement of TCP. The defects were evaluated clinically and radiographically utilizing standardized probe placement and radiographic technique. Clinically, there was a mean probing pocket reduction of 4.5 mm as a result of a mean gain of clinical probing attachment level of 2.0 mm and a mean gingival recession of 2.5 mm. Radiographically, there was a mean "fill" of 1.8 mm. Six teeth were removed by block biopsy for histologic analysis, three at 3 months, one at 6 months and two a 9 months. The TCP particles were well tolerated and encapsulated by fibrous connective tissue, but the particles did not stimulate new bone growth. The junctional epithelium ended 1.62 mm coronal to the apical extent of a reference notch placed at the base of the defect. Although new cementum was observed, there was limited evidence of new attachment.