Evaluating the implant candidate 219

Fig. 6-26. Leukoplakia appears here as a white, elevated fissured patch the more common form—and as an ulcerated lesion. (Courtesy Dr. Elliot W. Strong.)

Lichen planus. Lichen planus is a disease of unknown origin that is usually limited to the mouth. It may occur in two forms, simple and erosive. The simple form is characterized by poorly defined, slightly elevated lacework of bluish-white lesions with nodes at the intersections of the lines. Sometimes there are short linear extensions from the periphery of the lesion. The most common sites for lichen planus are the buccal mucosa opposite the molars, the margins of the tongue, and edentulous areas. The gingivae are rarely involved. The condition in its simplest form is not painful, easy to diagnose, and not dangerous.

The erosive form of lichen planus is painful and more difficult to diagnose. Its lesions are usually shallow, recurrent ulcerations that may also appear

Fig. 6-27. A, Leukoplakia is a precancerous lesion, with about one-quarter of the lip lesions developing into carcinoma. Here leukoplakia is seen across the entire lower lip, interrupted in the midline by a squamous cell carcinoma. B, Although the tongue is a less common site for leukoplakia than the cheeks or lips, the dorsum of this tongue is covered with numerous small leukoplakic lesions. The smooth, blanched elevated ridges on the side of the tongue are carcinoma. (Courtesy Dr. Elliot W. Strong.)