Vascularity and VEGF/VEGFR2 Signaling in the Dentine-Pulp Complex of Immature and Mature Permanent Teeth.

Objective: To examine the microvessel density (MVD) and spatial distribution of endothelial cells and angiogenic activity in immature and mature permanent teeth using immunohistochemistry.

Methods: Healthy third molars with immature and mature root development were formalin-fixed, decalcified in 10% ethylenediaminetetraacetic acid, and processed for routine immunohistochemistry with endothelial cell markers anti-CD34 and anti-CD146 and angiogenic markers anti-vascular endothelial growth factor (VEGF) and anti-VEGF receptor-2 (VEGFR2). Staining was visualized with diaminobenzidine and examined using light microscopy. The distribution of markers was analyzed qualitatively and quantitatively in the coronal, middle, and apical regions of the dentine-pulp complex.

Results: There were spatial differences in protein expression for immature and mature teeth. The pulps of immature teeth were more vascular, had a greater number of CD34+ and CD146+ cells, and a significantly higher MVD in the coronal region than those of mature teeth (P=0.03). The apical papilla contained few blood vessels. VEGF/VEGFR2 activity was significantly greater for immature teeth (P=0.001). VEGF was expressed throughout the pulp-dentine complex, but there was significantly more growth factor coronally (immature P=0.04 and mature P=0.02). VEGFR2 was expressed less than VEGF but was seen on the endothelial cells and single cells unrelated to a vessel lumen.

Conclusion: The spatial distribution of vascular and angiogenic (VEGF/VEGFR2) markers indicates the potential for altered healing responses in the pulps of immature and mature teeth. Immature teeth have a greater MVD and VEGF/VEGFR2 expression than mature teeth, and the increased expression of these markers in the coronal region of both tooth types is important for pulp healing.