[Experimental study of radiation effects on the mandibular microvasculature of the guinea-pigs]

In the experiment, both 180 kV X-ray and cobalt-60 radiation were delivered to right mandibles of 128 guinea-pigs with different dose (1000 cGy x 4, 800 cGy x 4, 600 cGy x 4, 400 cGy x 4 within 1 week). Dental extractions were conducted 1, 3, 5 months after radiation and the irradiated animals were examined by using microvascular corrosion castings of mandibles. It was found that the number of capillaries reduced and microvascular networks broke off after radiation with small veins shrinking subsequently while the alterations of arteries were slight. This result indicated that capillary was the most vulnerable part to the damage of radiation in the vascular system. In addition the defects of vascular networks around the non-healing tooth extraction sites were also discovered with irregularly capillary proliferation in the periphery of the lesion. The phenomena suggested that microcirculation failure induced by trauma-repairing process lead to occurRence of osteoradionecrosis of jaws.