OBJECTIVETo investigate the value of application of mandibular outer cortex as bone graft by comparing its bone absorption with cranial outer cortex.

METHODS8 minitype grown-up pigs at the age of 8 - 12 months underwent surgery of taking out the same size (2.5 cm x 1.0 cm) of outer cortex from mandible and craninium. The volume of the outer cortex was measured by volume-displacement method. Then the outer cortex of mandible and cranium were onlay grafted to the each side of the pig snout, respectively. 12 weeks later, 2 pigs were randomly selected for histological examination. The other 6 pigs were killed 24 weeks after surgery for measurement of the bone graft volume and histologic examination.

RESULTSThe bone graft absorption rate was (41 +/- 5)% for mandibular outer cortex and (46 +/- 12)% for cranial outer cortex, showing no significant difference between them (P = 0.51). The histologic examination results also had no marked difference in the bony healing and reforming between the two graft.

CONCLUSIONSMandibular outer cortex is a good donor site for onlay bone graft in craniofacial region.