This week I have a case of a common anatomical variant; mandibular tori. Mandibular tori can be evident on any mandibular periapical as well as bitewing radiograph. Mandibular tori will appear rounded over the roots and apices on anterior periapicals. On posterior periapicals, a increased radiopaque area is seen near the crest of the alveolar ridge and midroot portion of the teeth. Sometimes tori are very evident over the anterior teeth and barely noticeable on posterior teeth. This has to do with postioning of the film/sensor. On anterior periapicals, the positioning of the film/sensor tends to be that it is posterior to the tori so it will be more comfortable for the patient. This will have the x rays passing through a thicker area of the mandibular tori. Due to the increased thickness of bone, less x rays will make it to the film/sensor and create a more radiopaque area. On posterior periapicals, the x rays are passing through a thinner area of the tori and will not be as noticeable as in the anterior. Here is an example of mandibular tori in the anterior and mandibular tori in the posterior that are not as radiopaque on the same patient.
Anterior periapical: Note the radiopacity of the tori superimposed over the roots.
Posterior periapical: Note the increased radiopacity of the tori over the crest of the alveolar ridge and midroot portions of the teeth. The radiopacity is less than that on the anterior periapical.
For more information and other radiographs of mandibular tori check out the page on mandibular tori.
Enjoy!