Sickle cell gnathopathy: radiologic assessment.

To provide objective evaluation of sickle cell gnathopathy, lateral skull radiographs of fifty patients with sickle cell anemia and twenty-five controls, matched for age and sex, were evaluated with respect to hard palate length and palate--alveolar ridge (PAR) angle. These measurements were compared to the angle formed between sella, nasion, and a point just below the anterior nasal spine of the maxilla (SNA angle), which is widely used in evaluation of the midfacial skeletal profile. The maxillary protrusion was found to be due to an increase in the PAR angle, as there was significant difference in this measurement between the two groups while there was no difference in the hard palate and SNA angle measurements. In keeping with prior explanations, marrow hyperplasia is the cause of maxillary overgrowth. Although often detected clinically, sickle cell gnathopathy can be evaluated radiographically simply and accurately by measurement of the PAR angle.