The simple bone cyst (SBC) is a pseudocyst that can occur as a solitary entity in the jaws or may occur in association with cemento-osseous dysplasia (COD).
Objective: The purpose of this study was to review the clinical and radiographic features of solitary and COD-associated SBCs.
Methods: Archived imaging reports from the Special Procedures Clinic in Oral and Maxillofacial Radiology at the Faculty of Dentistry at the University of Toronto between 1 January 1989 and 31 December 2009 revealed 23 COD-associated SBCs and 68 solitary SBCs.
Results: Almost all solitary and COD-associated SBCs were found in the mandible. Furthermore, 87.0% of COD-associated SBCs were found in females in their fifth decade of life (P < 0.001) while solitary SBCs were found in equal numbers in both sexes in their second decade of life (P < 0.005). COD-associated SBCs were also more likely to cause thinning of the endosteal cortex, bone expansion and scalloping of the superior border between teeth (all P < 0.001) than solitary SBCs that are classically described as having these characteristics. Finally, COD-associated SBC demonstrated a loss of lamina dura more often (P < 0.05) than solitary SBCs.
Conclusions: Knowledge of the sporadic association between COD and SBC and their potential radiographic appearances should prevent inappropriate treatment and management of these patients.