[Novel calcium phosphate formula for filling bone defects. Initial in vivo long-term results].

BACKGROUND

Up to now hydroxyapatite (HA) and beta-tricalciumphosphate (beta-TCP) ceramics have been routinely sintered at temperatures between 1100 degrees and 1500 degrees C. Our new calcium ceramic is fabricated by a sol-gel process at 200 degrees C. The aim of this investigation was to test the biodegradation of and the induction of bone formation by this material.

MATERIAL AND METHODS

Eighteen 1-year-old Goettingen minipigs were divided into three groups. Critical size defects (>5 cm(3)) in the mandible were treated differently in all three animals (group 1: filling with 40% beta-TCP plus 60% HA, group 2: pure HA was applied, group 3 served as controls: only gelatinous material was given). Macroscopic and microscopic investigations of the former defects were made 8 months postoperatively. RESULTS. In groups 1 and 2 biodegradation of more than 93% of the new calcium phosphate formula was found 8 months postoperatively and considered to be very good. No difference was observed between pure HA (group 2) and the combination of HA and beta-TCP (group 1). In both groups complete bone formation was seen macroscopically in the former defects. In the control group only incomplete bone formation with 48.4% of the defect area was noted. This difference was significant ( p<0.001).

DISCUSSION

The new calcium phosphate formula made by a sol-gel method at 120 degrees C seems to be suitable for filling bone defects and is of interest for orthopedic surgery, traumatology, craniomaxillofacial surgery, and dentistry.