Night pain in a restorable first molar: pulpitis or infection?
A 42-year-old man attends a public dental clinic with severe pain in the lower right first molar (46) that has worsened over four nights. He describes sharp pain triggered by cold drinks that persists for about 30 seconds after the stimulus is removed, and pain that wakes him from sleep. He has taken amoxicillin 500 mg three times daily for three days, obtained from a nearby pharmacy, without relief. Examination shows a deep occlusal carious lesion, no swelling, no sinus tract, and probing depths of 3 mm or less. The tooth is mildly tender to percussion but not mobile. A periapical radiograph shows caries extending to the pulp but no periapical radiolucency, and the tooth is restorable. He is systemically well, has no drug allergies, and asks you to 'just pull it out' because he cannot afford multiple visits.
1. What is the most likely diagnosis, and which findings support and argue against the main alternatives?
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Most likely diagnosis: symptomatic irreversible pulpitis of 46.
- Supports it: spontaneous pain that wakes the patient, pain lingering about 30 seconds after cold is removed, deep caries reaching the pulp, and a restorable tooth.
- Against reversible pulpitis: reversible pain is provoked and resolves almost immediately; this pain is spontaneous and prolonged.
- Against acute apical abscess: there is no swelling, no sinus tract, no periapical radiolucency and no systemic upset. Mild percussion tenderness is common in pulpitis because of early periapical inflammation and does not by itself mean an abscess.
- Against a periodontal cause: probing depths are 3 mm or less and there is no mobility, while the primary lesion is clearly caries.
- The failed antibiotic course is not evidence against pulpitis: systemically administered antibiotics do not penetrate a necrotic, closed pulp space, so failure to respond is expected.
2. Describe your immediate clinical management and the reasoning behind each step.
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- Explain and consent. The tooth is restorable, so root canal treatment plus a crown is the predictable option; extraction is reasonable only if the tooth is unrestorable, the patient prefers it after informed discussion, or resources make root canal treatment impossible. Explore a phased or single-visit plan if cost is the barrier.
- Achieve pulpal anaesthesia. Inferior alveolar nerve block with 2% lidocaine 1:100,000 plus long buccal infiltration; confirm with a cold test or by absence of pain on access; a supplemental intraligamentary injection can rescue a hot tooth.
- Isolate and remove the source. Rubber dam, remove caries, access the chamber, amputate the coronal pulp and extirpate the canals, or perform a full pulpotomy if the canals are difficult. Never leave the tooth open to drain.
- Temporise and control pain. Well-sealed temporary restoration; ibuprofen 400 mg every 6-8 hours with food, with paracetamol as an alternative or adjunct. Arrange completion of root canal treatment and crown.
3. The patient insists that antibiotics will cure the tooth and asks for another course. How do you respond, and when would antibiotics be justified?
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Antibiotics will not cure this tooth because the bacteria are inside the necrotic pulp space, where systemic drugs do not reach in effective concentrations; the definitive treatment is removal of that tissue. There are no systemic signs, no swelling and no trismus, so antibiotics are not indicated for irreversible pulpitis alone.
Risks of unnecessary antibiotics include gastrointestinal upset, allergy, Clostridioides difficile infection and selection of resistant organisms.
I would use antibiotics when there is spreading infection or systemic involvement - facial swelling, trismus, fever, malaise, lymphadenopathy - or in an immunocompromised patient. They are an adjunct to drainage, not a substitute for it. I would document the discussion, offer analgesia and a clear appointment, and explain that a second course would delay the treatment that actually works.