Imaging appearance of odontogenic lesions on CT

In this video, Dr. Katie Bailey gives us an overview of odontogenic lesions, or those lesions related to the teeth and their imaging appearance on CT. In this talk, we will review some of the most common odotogenic lesions and their imaging appearance so you are familiar with them when you see them.

Introduction

Odontogenic lesions are lesions of the jaw that are associated with a tooth or a component of a tooth. They are usually above the level of the alveolar canal, unlike non-odontogenic lesions. One common strategy for helping make your differential is to divide them into radiolucent lesions and radiopaque lesions

Infection

If you see an infection of the sinuses, you should take a look at the adjacent teeth. Dental and periodontal disease can affect the sinuses, particularly the adjacent maxillary sinus. When there is a connection between lucency around a tooth which is directly connected with the sinus, it is called an oroantral fistula, and can either cause inflammation of the sinus or lead pus directly into the sinus.

Radicular cyst

Radicular cysts are the most common asymptomatic cysts. They are usually less than 1 cm and are associated with the root of a tooth. They have a well defined margin which is sclerotic and larger than the typical circumferential periapical lucency.

Residual cyst

A residual cyst is a cystic lesion that remains at the site of a previously extracted tooth. It also has a thin rim with a sclerotic margin, but the tooth is absent.

Dentigerous cyst

These are usually seen in younger adults and surround the crown of an unerupted tooth. This is most common with more posterior molars, such as the third molar.

Odontogenic keratocyst

These are usually also associated with unerupted teeth, and are most common seen along the posterior body and ramus of the mandible. They are often well-defined and expansile. On MRI, they often have restricted diffusion with a rim of enhancement

Ameloblastoma

Ameloblastoma is the most common odontogenic tumor. They are benign but locally aggressive. They are radiolucent and can have one or more cysts. They can have cortical breakthrough and a soft tissue component. While they look like odontogenic keratocysts, they are usually NOT associated with a tooth.

Odontoma/Supernumerary teeth

This is a sclerotic lesion which has a toothlike resemblance and occur in the posterior maxilla or mandible. They can also be associated with a tooth or residual tooth.

Cemento-osseous dysplasia

This is a replacement of bone into a mix of cementum, bone, and fibrous connective tissue. They can be single or multiple and can be associated with the apex of a tooth (peri-apical), focal, or widespread (florid). In these cases, there is ill-defined hyperdense or ground glass extending through the bone of the mandible.

Cementoblastoma

These are cementum forming tumors associated with the tooth root, most commonly the first molar. There is an area of sclerosis at the rooth of a tooth with a rim of surrounding lucency.

Condensing osteitis

This is local reactive sclerosis from chronic inflammation or infection. This is often associated with a tooth that has caries or periodontal inflammation.

Summary

Thank you for checking out this video and short tour of the range of odontogenic lesions you might see. There is a lot of overlap between these lesions, but hopefully you can start to recognize some of the key features.

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