The Bridge That Never Settled

Correct answer: B. Chronic apical abscess

• A. Symptomatic apical periodontitis gives pain to percussion and biting, but there is NO sinus tract and no drainage. The parulis is what moves the diagnosis past this label.
• B. CORRECT. A previously treated, non-responsive tooth with a periapical radiolucency and an INTERMITTENTLY DRAINING SINUS TRACT (the red bump on the gingiva, a parulis) is a chronic apical abscess. The defining feature is the tract — continuous low-grade drainage vents the pressure, which is why these lesions are usually only mildly symptomatic despite an obvious radiolucency.
• C. Condensing osteitis is a RADIOPAQUE (sclerotic) reaction to chronic low-grade pulpal inflammation, not a radiolucency with drainage.
• D. An acute apical abscess presents with rapid onset of severe pain, diffuse swelling, malaise and often fever, WITHOUT an established drainage pathway. Radiographic change may be minimal because the process is too fast for bone to resorb.

Note: Trace every sinus tract with a gutta-percha point before assuming which tooth is responsible. The tract does not always lead where you expect.

Correct answer: D. The incisive foramen (nasopalatine canal)

• A. A lateral periodontal cyst occurs most often in the mandibular canine-premolar region, along the lateral root surface, and is uncommon in the anterior maxilla midline.
• B. An OKC is typically a larger, well-corticated lesion of the posterior mandible or ramus and would not present as a small midline interdental lucency.
• C. A periapical granuloma would be centred ON the apex of a NON-VITAL tooth. This lucency sits interdentally between the roots, and #8 has not been described as non-vital.
• D. CORRECT. The INCISIVE FORAMEN projects in the midline between the maxillary central incisors as a well-defined, often heart-shaped or ovoid radiolucency. It is a normal anatomic structure and the single most common cause of a midline anterior maxillary radiolucency. Confirm by changing the horizontal angulation — an anatomic structure SHIFTS relative to the roots, while a true periapical lesion stays anchored to the apex — and by pulp-testing both centrals.

Note: The rule: if the lucency moves when the beam angle changes, it is not endodontic. If it stays glued to the apex, it is.

Correct answer: C. Complete the root canal retreatment — the tract closes once the source is eliminated

• A. Excising the tract is unnecessary and it will simply re-form if the source persists. If a tract fails to close within a few weeks of adequate treatment, THEN reassess for a missed canal, a vertical root fracture, or a non-endodontic lesion.
• B. Incision and drainage is for a FLUCTUANT acute swelling with no drainage pathway. This lesion is already draining — the pressure is vented.
• C. CORRECT. A sinus tract is a SYMPTOM, not a disease. It is epithelium-lined granulation tissue that exists only because infected necrotic pulp is feeding it. Eliminate the intracanal infection with (re)treatment and the tract resolves spontaneously, usually within days to a couple of weeks. No separate surgical or antibiotic management is required.
• D. Antibiotics are not indicated for a localized chronic apical abscess in a healthy patient with no systemic signs. They do not reach the necrotic canal, which has no blood supply, and only delay definitive care.