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OBJECTIVES The aim of this investigation was to evaluate the clinical and histological differences in wound healing between beveled and perpendicular vertical releasing incisions in dogs. MATERIAL AND METHODS Four male mongrel dogs were used in this investigation. In each quadrant, a vertical releasing incision was made on either the mesial or the distal aspect of the cuspid teeth of each animal all on the same day. The sites were randomly selected to either receive a beveled incision or a perpendicular incision. A sulcular muco-periosteal flap was raised, reapproximated, and then sutured using 3-0 vicryl. The animals were evaluated daily for the first week, and then at different time intervals during this investigation. One animal was sacrificed at each time interval of 9, 14, 21 and 28 days after surgery. One animal was sacrificed at each time interval, and a bone block consisting of the cuspid teeth and their surrounding bone and soft tissues were harvested, formalin-fixed, and paraffin embedded. Samples were sectioned serially and stained with H&E. Specimens were evaluated using a microscope with magnification ranging from 10X to 400X by a histopathologist. Four indices were used for histological evaluation. RESULTS Clinical results: At day 9 after surgery, a visible groove was seen in the marginal tissues of both perpendicular and beveled incisions. In the 14-day samples, a depression was still present at the perpendicular incision sites, but not in the beveled incision group, where the groove was not visualized at all. Histological results: At day 9, both of the histological sections showed less organized connective tissue and capillary networks with no significant difference in inflammation. At day 14, a depression was still present in the perpendicular incision but not in the beveled incision sites. In the 21 and 28 day samples, irregular capillary arrangements were seen in the connective tissue of the perpendicular incision groups with completely healed epithelium. There were no statistically significant differences noted histologically between the beveled and perpendicular incision groups noted at 9, 14, 21 or 28 days (P >0.05). CONCLUSION Based on these findings, it appears that clinical and histological healing of beveled or perpendicular releasing incisions are similar 28 days post-surgery.