Endodontics · patient case question
If that cervical barrier is omitted and the root filling is not properly sealed before internal bleaching, what is the characteristic complication?
Patient case: The Betel Quid Chewer
Patient: 44-year-old male
Chief Complaint: “One of my front teeth is much darker than the others.”
Background: Emigrated from South Asia. Chews betel quid daily for over twenty years. History of trauma to the upper front teeth in his twenties.
Medications: None
Vital Signs: BP 130/82 mmHg · HR 76 bpm · RR 16 · T 98.4°F
Findings: Generalized reddish-brown extrinsic staining of the dentition and mucosa. Gingival recession. Tooth #8 is uniformly grey-brown from within — clearly different in character from the surface staining — and did not respond to pulp testing. Root canal treatment on #8 has just been completed. The crown is otherwise intact with no caries and no restoration.
Show answer and explanation
Correct answer: C. External cervical resorption
- A. Apical resorption relates to orthodontic force, periapical inflammation or trauma, not to a coronal bleaching agent.
- B. Ankylosis is the fusion of root to bone following loss of the periodontal ligament, typically after avulsion or severe luxation — an entirely different mechanism.
- C. CORRECT. EXTERNAL CERVICAL (invasive) RESORPTION is the recognised complication. Bleaching agent — particularly heated 30% hydrogen peroxide — diffuses through the dentinal tubules and out through the patent tubules at the cementoenamel junction, where the cemental covering is thin or absent in a substantial proportion of teeth. The resulting inflammation in the periodontal ligament initiates a clastic resorptive lesion at the cervical level, which is often silent until it is advanced.
- D. Internal resorption originates from the PULP and requires vital pulp tissue and odontoclasts within the canal. This tooth has no pulp.
Note: Two protective measures: the cervical barrier described above, and avoiding the heated thermocatalytic technique. Sodium perborate with water in a sealed chamber is both safer and effective.