Dentigerous cyst of the maxilla and its image diagnosis.

Dentigerous cysts may grow unnoticed to such extensive sizes as to occupy a considerable portion of the maxillary sinus. As they enlarge, the bony walls overlying the cysts thin out giving rise to an egg shell sensation upon palpation. Three cases of such extensive dentigerous cysts were experienced since 1987. These three cases were used to illustrate the advantages and disadvantages of the following imaging techniques in the preoperative evaluation of these cysts, conventional radiographs, sonography, CT, and MRI.