220 Theories and techniques of oral implantology

on the gingivae. The lesions may be widespread and may be confused with recurrent herpetic stomatitis and erythema multiforme. Biopsy is often necessary to confirm the diagnosis.

Lichen planus may occur at any age. Although its cause is not clearly understood, it appears to be triggered by emotional upset, physical or mental stress, and menstruation in some cases. The condition is chronic, but not precancerous, and responds poorly to treatment.

Because the condition appears in patients who may be continually apprehensive and prone to emotional upset, the dentist can take the presence of lichen planus as a warning that the patient may be too unstable for an implant procedure. (See Emotional Stress, p. 248.)

Leukoplakia. Leukoplakia is a chronic, precancerous disease characterized by whitish, stiff, leathery patches on the lips, tongue, floor of the mouth, and buccal mucosa. It may also occur in edentulous

areas but is rare on the gingiva. Advanced lesions are painful and may ulcerate (Fig. 6-26).

Leukoplakia results from chronic irritation of the mucosal tissues. Some of the physical agents causing it are jagged teeth or fillings, trauma from loose-fitting dentures, or unsatisfactory dental restorations with sharp margins. Chemical agents include hot, highly seasoned foods and tobacco, which may account for its prevalence in men, who tend to smoke more than do women. Poor oral hygiene combined with bacterial irritation may also produce the condition.

Usually leukoplakia can be easily recognized by its characteristic lesions and its reaction to Lugol's solution. After the suspicious area is dried, painted with Lugol's solution, and rinsed, the leukoplakic areas remain unchanged while the surrounding mucosa is stained a deep mahogany brown.

Because leukoplakia is precancerous—and even a small patch, particularly one on the mandibular

Fig. 6-28. Inspecting the patient for cancer: the head and neck should be inspected at various angles for swellings and asymmetry. (Photographed by Ralph Basabe.)