VASCULAR CHANGES FOLLOWING MUCOPERIOSTEAL FLAP SURGERY - A FLUORESCEIN ANGIOGRAPHY STUDY IN DOGS

THIS STUDY WAS UNDERTAKEN TO DETERMINE the vascular changes which occu r following mucoperiosteal flap surgery where two different suturing t echniques were employed. In four healthy adult mongrel dogs, buccal an d lingual full-thickness envelope flaps were reflected in the mandibul ar quadrants following intracrevicular incisions from the first premol ar to the first molar. The flaps were immediately readapted and primar y closure was achieved by the horizontal mattress suturing technique i n one quadrant and the direct interrupted suturing technique in the co ntralateral quadrant of each dog. A simple photographic system was dev eloped for recording the in vivo gingival circulation depicted by fluo rescein angiography just prior to surgery and then after surgery on da ys 1, 3, 7, 10, 14, and 21. The flaps were divided into three interpro ximal and two mid-buccal sites for analysis and the intracapillary and diffusion extent of dye fluorescence was accurately quantified by com puterized planimetry. As healing progressed, longitudinal changes rela tive to presurgical baseline were analyzed by paired t-test. Cross-sec tional comparisons utilizing Student t-test allowed for evaluating dif ferences between the two suturing techniques as well as differences be tween interproximal versus mid-buccal sites at each postsurgical day. It was found that the simple act of raising a mucoperiosteal envelope flap initiates significant vascular trauma. Statistically significant reductions in flap circulation relative to presurgical baseline lasted for at least 3 days but persisted for 7 days at the interproximal sit es. Flap diffusion (extravascular leakage) recovered sooner and extend ed over a significantly greater area of the flap than did intracapilla ry flap circulation during the early period of healing. No significant differences appeared between the two suturing techniques compared, al though both may have exerted a local negative influence on the circula tion until they were removed.