The irradiated human mandible: A quantitative study on bone vascularity

•Irradiation decreases mandibular vascular density and vascular number.•In local dosages exceeding 50 Gy, the proportion of smaller vessels decreases.•With increased time after radiotherapy, the proportion of smaller vessels decreases. Hypovascularisation is thought to play an important role in the pathogenesis of osteoradionecrosis. The objective of this study was to assess the microvascular system in the irradiated mandibular bone marrow. Mandibular bone biopsies were taken from 20 irradiated patients and 24 controls. Blood vessels were visualized using CD34 antibody stain to detect endothelial cells. The vascular density (VD) and vascular area fraction (VAF) were measured. Mean vessel lumen area, perimeter and diameter of the vessels were calculated for each vessel. A distinction was made between large and small vessels (cut-off point