Evaluating the implant candidate 209

Fig. 6-12. In the mandible a large radiolucent area with a scalloped upper border may be indicative of a traumatic cyst. (From Bhaskar, S. N.: Synopsis of oral pathology, ed. 3, St. Louis, 1969, The C. V. Mosby Co.)

Fig. 6-13. This large, bone-distorting radiolucent lesion is an aneurysmal bone cyst. (From Bhaskar, S. N.: Synopsis of oral pathology, ed. 3., St. Louis, 1969, The C. V. Mosby Co.)

are lined by a very thin layer of connective tissue. The cause of this empty lesion is unknown, but lysis of a blood clot or of a benign tumor or faulty calcium metabolism are among the explanations.

Untreated, a traumatic cyst may persist for a long time. Treatment, including curettage and closure of the site, usually brings prompt, uneventful healing of the defect.

The aneurysmal bone cyst usually enlarges the jaw but does not destroy the cortex. Radiographically, this lesion appears as a soap bubble–like radio-lucency, although it is unilocular (Fig. 6-13). This type of pseudocyst is filled with a liver-like tissue that bleeds easily. Local curettage is usually adequate to cure the condition.

Fig. 6-14. The idiopathic bone cavity, a type of pseudocyst, occurs well away from an implant site. (From Bhaskar, S. N.: Synopsis of oral pathology, ed. 3, St. Louis, 1969, The C. V. Mosby Co.)

As previously stated, both the aneurysmal bone cyst and traumatic cyst generally occur in young people. Because the typical implant candidate is generally in his or her mature years, such pseudo-cysts will be rare in presenting candidates.

Another type of pseudocyst, the idiopathic bone cavity, may be seen in a presenting patient. This false cyst occurs in the mandible, usually at the base of the mandible between the angle and the first molar (Fig. 6-14). The cavity may contain lymphoid or connective tissue or a part of the submaxillary or sublingual glands that became included during development. This lesion is painless and requires no treatment. Because the cavity is well away from the alveolar crest, lying below the dental canal, the