Coronoid Hyperplasia with Zygoma Osteoma on Orthodontic Evaluation

An 18-year-old female with no significant medical history was referred for routine orthodontic evaluation. Upon review, the radiologist identified severely elongated and thickened coronoid processes bilaterally, a condition that can limit mouth opening and mandibular range of motion. The radiologist also noted that one of the zygomas had developed an osteoma, likely from repeated contact with the coronoid process during mouth opening. The radiologist noted that the etiology of limited mouth opening can be difficult to determine and is often attributed to TMJ disorder, but coronoid hyperplasia can be surgically corrected with a very good prognosis. The development of a zygoma osteoma from repeated traumatic contact is a very rare finding.