Periodontal microcirculation as revealed by plastic microspheres

Plastic microspheres 15 ± 5 microns were injected into the right external carotid artery of five Squirrel monkeys. One animal was sacrificed at 1, 24 and 36 hours and two animals at one week. The jaws were removed, fixed, demineraized and sectioned bucco‐lingually. The vascular patterns in the connective tissue beneath the oral epithelium, epithelial attachment, “col” area and within the periodontal membrane were examined. The vascular tree supplying the oral epithelium was visualized as running perpendicular to the outer surface while that in the attachment area paralleled its epithelial surface. The “col” area, on the other hand, demonstrated a combination of both vascular patterns. The diameter of the terminal arterioles just beneath the epithelial basement membrane ranged from 13.6 to 20.4 microns and varied little in the three areas examined. The vessels within the periodontal ligament were connected into a net‐like plexus receiving its primary bloodsupply from vessels penetrating the lamina dura perpendicularly.