I almost missed this lesion on the radiograph

I almost missed this one. I’m doing my thing, jumping from room to room, and I caught it at the last minute while doing a routine exam. Take a gander at the radiograph in Figure 1 and see if you catch it quickly or if it takes you a second. The lesion is supervague, but it’s there. Do you see it?

The distinct radiolucency on no. 25, just below the lower apical half of the tooth, is external resorption. The key diagnostic feature that differentiates it from internal resorption is the fact that the canal is defined. The CBCT confirms this, of course.

The patient presented asymptomatic (as these lesions usually are), and after discussion, we moved forward with a referral for assessment of extent and considerations for anticipated replacement.

Figure 2 is another radiograph that did not bode well for the patient. No. 18 was diagnosed with internal resorption, and no. 17 was also in the beginning stages when the CBCT scan was taken. Both were removed and an implant was placed in the no. 18 site.

External and internal resorption are some of the vaguest, yet greatest, topics of interest we have in dentistry. Their genesis, how they “behave,” and treatment modalities are indeed a conundrum. A refresher is always warranted. Take a look at these two articles (links below) that I’ve written on this topic. They’re worth a read or at least a quick scan.

• Endodontics reference guide: Distinguishing differences between internal and external resorption
• Internal resorption: A brief review and case report

Editor’s note: This article first appeared in Through the Loupes newsletter, a publication of the Endeavor Business Media Dental Group. Read more articles and subscribe to Through the Loupes.