Relative gene expression levels of alkaline phosphatase (A), osteopontin (B) and osteocalcin (C).

Alveolar bone cells isolated by explant cultures (grey bars) and by collagenase digestion (black bars) from 13 different patient samples were cultured separately and evaluated at the second passage. Data show expression levels of individual samples normalized to the osteoblastic control sample (-fold change). No significant differences in expression levels were found between cells from the two different isolation procedures (p>0.05).