Endodontics · patient case question
What is the diagnosis for the periapical lesion associated with tooth #14?
Patient case: The Pimple That Comes and Goes
Patient: 52-year-old female
Chief Complaint: “There’s a pimple on my gum that comes and goes. It’s been almost two years.”
Background: Healthy, no medications. Describes intermittent swelling that drains, subsides for weeks, then recurs. Minimal pain throughout.
Medications: None
Vital Signs: BP 124/78 mmHg · HR 72 bpm · RR 16 · T 98.4°F
Findings: Tooth #14 has no restoration and has never received endodontic treatment. It gives no response to cold and is not tender to percussion. A well-defined periapical radiolucency is present, and a gutta-percha point placed in the sinus tract tracks radiographically to the apex of #14. Separately, tooth #29 has a fractured lingual cusp. Tooth #17 is horizontally impacted and its crown contacts the distal root of #18, which shows a concave radiolucent defect at the point of contact.
Show answer and explanation
Correct answer: D. Chronic apical abscess with pulp necrosis
- A. Incorrect. A nasopalatine duct cyst is a developmental cyst in the midline anterior maxilla, appearing as a heart-shaped radiolucency between the central incisors. It is unrelated to a molar apex.
- B. Incorrect. A periodontal abscess arises from a periodontal pocket in a tooth with a vital pulp and normal thermal response. This tooth is non-responsive to cold and the tract traces to the apex.
- C. Incorrect. A residual cyst forms from epithelial rests left behind after a tooth is extracted. Tooth #14 is present, so the term cannot apply.
- D. Correct. Pulp necrosis with an associated sinus tract that drains intermittently over a prolonged period, with minimal pain, defines a chronic apical abscess. The gutta-percha tracing confirms the source, which is the single most useful diagnostic step in a draining lesion.
Note: Caries is not the only route to necrosis. A tooth with no restoration and no caries can lose vitality through occlusal trauma, a crack, attrition, or a remote traumatic event. Always trace a sinus tract with gutta-percha before assuming which tooth is responsible.