Capillary blood circulation following experimental wounding was observed by fluorescein angiography. Contralateral punch wounds 1.5 mm in diameter were made in healthy mandibular labial attached gingiva of 31 volunteers. Areas of ischemia were clearly visible angiographically 6 hours after wounding and were significantly greater in area (P less than 0.05) and wider (P less than 0.01) for wounds in the long axis of mandibular incisors (N = 14) than those on the vertical midline of the gingival papillae (N = 17). The ischemic changes occurred exclusively cranial to the experimental wounds. By the third day the epithelium adjacent to the wound margin in the central part of the ischemic area had necrotized, thus extending the wound coronally. By the seventh day the axial wounds were significantly (P less than 0.001) larger than the papillary wounds. The data strongly suggest that the blood supply of mandibular labial attached gingiva is preferentially oriented in an apico-coronal direction and that the capacity for collateral circulation is dependent upon local differences in vascular structure. The findings are applicable to flap design in periodontal surgery.
