Bioceramic implants in surgical periodontal defects. A comparison study

The healing response of two commercially available bioceramics, beta tricalcium phosphate (TCP) and hydroxylapatite (HA), was compared after implantation in surgically created defects in dogs. Three 18 to 24 month old female Labrador dogs were used. Under general anesthesia 3-wall defects were created on the canines and premolars. The roots were planed, and reference notches were placed to identify the alveolar crest and the apical extent of the defects. TCP or HA was placed in alternating canine defects. The premolars received no implants and served as controls. Plaque management was accomplished by biweekly brushing with 0.2% chlorhexidine. Following healing periods of 5, 12 and 16 weeks, the dogs were sacrificed and perfused with 10% formalin. Six-mu step serial sections were evaluated by light microscopy. Healing against the root planed surface varied from a long junctional epithelium to a connective tissue reattachment in new cementum. TCP particles were actively resorbed by giant cells and macrophages and were incorporated into new bone matrix. The HA particles were encapsulated by fibrous connective tissue and rarely seen in contact with repairing bone. Bone formation was slower around HA particles at all time periods. Some evidence of HA particle resorption was seen at each time period.