Postoperative changes

After fractures, removal of teeth, cysts and tumors, healing takes place with varying speed and results. Normally, new bone formation can be seen in three to six months. However, in radiographs taken after extraction of teeth the alveoli may appear "empty" several years after extraction. This may be attributed to loss of functional stimulus whereby the primary bone remains instead of being replaced with regularly organized bone. Often, the surgical entrance to a lesion leaves a fibrous scar and a defect in the cortical plate, especially if there is a through and through defect. A fibrous scar is usually seen as a distinct radiolucency lined by a broad sclerotic zone with radiolucent radiating striations (Fig. 57). It can be mistaken for recurrences. However, initially a recurring cyst or benign tumor usually presents as a small spherical radiolucency with thin cortical borders which can appear as soon as one year after surgery. It may, however, take several years until a recurrence becomes evident radiographically. This is in particular true for some keratocysts (Fig. 58).

Lars Hollender and Karl-Åke Omnell