Edema is an accumulation of fluid in the interstitial space because of transudation from damaged vessels and lymphatic obstruction by fibrin. Two variables help determine the degree of postsurgical edema. First, the greater
the amount of tissue injury, the greater the amount of edema. Second, the more loose connective tissue that is contained in the injured region, the more edema is present. For example, attached gingiva has little loose connective
tissue, so it exhibits little tendency toward edema; however, the lips and floor of the mouth contain large amounts of loose connective tissue and can swell
The dentist can control the amount of postsurgical edema by performing surgery in a manner that minimizes tissue damage. Some believe that ice applied to a freshly wounded area decreases vascularity and thereby
diminishes transulation. However, no controlled study has verified the effectiveness of this practice. Patient positioning in the early postoperative period is also used to decrease edema by having the patient try to keep the
head elevated above the rest of the body as much as possible during the first few postoperative days. Short-term, high-dose systemic corticosteroids can be administered to the patient and have an impressive ability to lessen inflammation and transulation (and thus edema). However, corticosteroids are useful for edema control only if administration is begun before tissue is damaged.