A 50-year-old Malay male with a known history of dyslipidemia, gout, and asymptomatic hepatitis B presented to the dental clinic due to continuous throbbing pain in the lower right teeth, which started 3 days ago. The pain disrupts his daily activities and is alleviated with painkillers. He has a history of a restoration on tooth #47 done a year ago. Since then, he has experienced recurrent, intermittent dull throbbing pain. The pain radiates to the right cheek, right temple, right cervical area, and right side of the back.
He is under otorhinolaryngology and neurology follow-up for Ramsay Hunt syndrome, involving cranial nerves VII and VIII, with symptoms of vertigo and right lower motor neuron facial weakness, which resolved after two completed doses of prednisolone. Otherwise, he has no history of facial trauma or surgery. His SpO2 slightly dropped from 98–95% when the dental chair was tilted back. The patient feels uncomfortable when the dental chair is tilted back and begins breathing through his mouth. He cannot tolerate a mouth prop well, as it makes him feel like he is drowning.
The patient tends to tilt his head to the right (Fig. 1A). His bilateral temporomandibular joint is palpable during translation and non-tender. His mouth opening is 35 mm, with right lateral excursion at 10 mm and left lateral excursion at 8 mm. He experiences discomfort in mouth opening, with a forced and stretching sensation on his right lower cheek when yawning. His mouth opening is tense and requires effort during the assessment of maximum mouth opening. There is a palpable, firm, fixed, and tender mass at the right submandibular area, measuring 4 cm x 1 cm. He reports no pain or difficulty with neck movement. An intraoral examination (Fig. 1A & 1B) shows that his lower dental midline is shifted 3 mm to the right compared to the upper midline. He has a modified Mallampati score of IV, with a medium-sized scalloped tongue.
Figure 1A. A front profile extraoral photo shows a neutral head position, with the patient tending to slant his head toward the left side (the less affected side). B. An intraoral photo shows the dental midline shifted to the right by about 3 mm and multiple bony exostoses over the lower anterior attached gingiva. C. An intraoral photo shows the patient mouth opening with evidence of a scalloped tongue.
A panoramic radiograph was taken for a full dental assessment (Fig. 2A). The imaging reveals a linear ossification extending from the bilateral regions of the mastoid process and crossing the posteroinferior aspect of the ramus. The radiopacity on the right side is interrupted by radiolucent joint-like junctions (pseudo-articulation). Cone beam computed tomography (CBCT) was performed to further investigate the lesion (Fig. 2B, 2C, 2D). There is mixed radiopaque calcification on the right side, which extends longer toward the hyoid bone compared to the left side. Evidence of a fracture is present at the medial part of the right calcified stylohyoid ligament. The left calcified stylohyoid ligament extends to the body of the mandible.
Diagnosis of asymptomatic ossification of the bilateral stylohyoid ligament (right side, type II, and the left side, type I) was made. No active management was done for the lesions. The patient and family members were explained regarding the condition and the possible complications that could happen. His otorhinolaryngology and neurology departments were also informed of the findings. The dental treatment was done with a prop-up condition, a rubber dam, and a mouth prop with oximeter monitoring.