Evaluating the implant candidate 233

Osteitis deformans. Osteitis deformans, or Paget's disease, is a chronic progressive disturbance in bone metabolism. It begins in the spongy bone marrow and spreads to other parts of the bone. Its advance is characterized by a decalcification and softening of the bone, followed by uncontrolled re-calcification. This new bone is not formed normally, along stress lines, but irregularly, causing thickening and deformation. The alternating advance of decalcification and recalcification gives the bone a mottled appearance in x-rays.

Osteitis deformans usually affects the long bones and those of the spine, pelvis, and skull, although any bone might be affected. When the skull is involved (Fig. 6-39), the jaws may or may not be affected. The maxilla is more commonly affected than the mandible, and one of the early clinical symptoms that a patient with an edentulous maxilla demonstrates is that his maxilla has grown too large for his denture.

When x-rays of the maxillae reveal dense, irregular, highly opaque areas that look like cotton-wool, Paget's disease should be suspected (Fig. 6-40). These cotton-wool lesions must be spread through the bone; if they are few or localized, some other condition is probably the cause.

The cotton-wool appearance, which is one typical symptom, results from a rearrangement of the bony trabeculae. These grow coarse, condense, and leave large spaces. Sometimes the trabeculae simply increase in number, become finer in texture, and align longitudinally, usually receding away from the teeth. This gives the entire bone a dense, granular appearance in radiographs (Fig. 6-41). No matter what changes occur in the character and arrangement of the trabeculae, in advanced cases the antral floor is almost always involved.

When the mandible is affected, the trabeculae generally become reduced in number, coarse, and oriented along the length of the bone (Fig. 6-42). Posterior to the cuspid area there are a minimum of intersections. Anteriorly there are intersections, and these, combined with the sparse, coarse, and straighter-than-normal trabeculae, produce irregularly large spaces interspersed with small dense radiopaque areas. Toward the midline the trabeculae may converge to form an unusually dense area. The cortex at the inferior margin of the mandible may lose its density and look laminated.

The structural irregularities in either or both jaws produce slight to very noticeable enlargement. Although the enlargement may at first appear to

Fig. 6-39. Osteitis deformans, also called Paget's disease, has resulted in cotton-wool—like lesions of the skull. In this case the maxillae are also severely involved. (From Soni, N. N.: A microradiographic and polarized light study of cementum in Paget's disease, J. Oral Med. 24:2, 1969.)

Fig. 6-40. The cotton-wool lesions typical of Paget's disease are widespread. Few or localized similar lesions are probably indicative of some other condition. (From Bhaskar, S. N.: Synopsis of oral pathology, ed. 3, St. Louis, 1969, The C. V. Mosby Co.)