Mandibular osteomas in unaffected sibs and children of patients with familial polyposis coli.

Orthopantomography of the mandible (OTM) showed osteomas in 3 of 34 non-affected sibs and children of the probands in 14 families with polyposis coli. The observed to expected ratio with osteomas was 0.35, which is not significantly lower than 1.0 and in accordance with the frequency in the normal population. Although the result does not enable a definite evaluation of the diagnostic value of OTM, the finding suggests that this method may be used as a supplement to regular proctosigmoidoscopic screening of first-degree relatives of polyposis patients.