This patient is a 3 year old MN Shih Tzu who below presented on referral after full mouth dental x-rays were performed during a routine scaling/polishing procedure. Gross oral exam revealed “missing” mandibular 1st premolars. Below are the dental radiographs of the area. What dental abnormality do you see and what is the appropriate treatment for this condition?
This patient had a bilateral dentigerous cyst due to unerupted mandibular 1st premolars. A dentigerous cyst is a fluid-filled sack within the alveolar bone surrounding an unerupted tooth. The cystic lining contains cells that assisted in enamel formation, but fluid accumulates when the tooth is trapped beneath the gumline. As the fluid accumulates, it destroys the bone surrounding the tooth. The longer the cyst remains undiscovered, the more likely this bone destruction will affect the surrounding teeth, requiring a more extensive surgery. The majority of cases I see on referral are from patients for whom this was an incidental finding during a routine dental procedure. Without performing full mouth dental x-rays on all patients, these cysts would go completely undetected. Particularly for brachycephalic patients, until a “missing” tooth is radiographed, it is not truly missing.
Treatment of dentigerous cysts involves extraction of the unerupted tooth and exploration of the area to completely debride the cystic lining from the defect. Without thorough debridement of the cystic lining, the fluid can recur. I typically fill the empty space with a bone grafting material and always take post-operative x-rays.
Post-operative x-ray with bone grafting material.