Night pain in a lower molar three hours from home
A 41-year-old woman attends a provincial referral clinic in Kampong Cham with a 5-day history of severe spontaneous pain in the lower right first molar (tooth 46), pain that wakes her at night and lingers about 30 seconds after cold drinks. She reports partial relief with paracetamol 500 mg plus ibuprofen 400 mg, but the pain now radiates to the ear. On examination there is a large distal carious lesion with a lost temporary restoration; the tooth is tender to percussion, probing depths are 3–4 mm all round, and there is no swelling or sinus tract. The bitewing shows caries extending to within 1 mm of the pulp with a widened periodontal ligament space at the mesial apex but no periapical radiolucency. Cold test produces a painful response lasting 40 seconds; the adjacent premolar responds normally. The clinic has an electric motor and rotary files up to 25/.06, paper points and sodium hypochlorite 3%, but no apex locator, no CBCT and no microscope. The patient's home is a three-hour bus ride away and she cannot return within two weeks.
1. State the pulpal and apical diagnosis for tooth 46 and justify each element. Which single feature of this case most changes your treatment decision, and why?
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Diagnosis: symptomatic irreversible pulpitis with symptomatic apical periodontitis (tooth 46).
Reasoning element by element:
- Spontaneous pain that wakes her at night and radiates to the ear indicates a pulp that can no longer heal. Reversible pulpitis does not wake patients at night. The lingering 40-second response to cold confirms A-delta and C-fibre involvement, i.e. irreversible disease.
- Caries to within 1 mm of the pulp on the bitewing supplies the cause and explains why a conservative pulpotomy is not a durable option in a mature tooth whose canal system is already partly calcified.
- Tenderness to percussion and a widened PDL space without radiolucency indicate early symptomatic apical periodontitis. The absence of a radiolucency does not argue against it: radiographic change lags behind inflammation by weeks. There is no swelling and no sinus tract, so this is not an acute apical abscess and no incision or drainage is needed.
- Probing 3–4 mm excludes a periodontal abscess and a cracked root as the primary cause.
The feature that most changes the plan is the three-hour journey and the two-week no-return constraint, not the pulpal diagnosis itself. It turns the case from "provide ideal endodontics at leisure" into "you have effectively one appointment in which to achieve a bacteria-tight result." Every subsequent choice follows: complete the treatment in a single visit if possible, rely on radiographic working length, and keep a low threshold for referral or extraction rather than leaving an under-instrumented tooth sealed with a temporary this patient cannot have replaced.
2. Describe how you would locate and negotiate the calcified distal canal using only the equipment listed, and state three objective criteria that would make you stop and refer.
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Work from the coronal end outwards; never hunt apically with a file in a canal you cannot see.
- Access. Remove all caries and restoration remnants and fully deroof the chamber. A straight-line access is the single most useful instrument you have. Slight widening of the distal part of the chamber with a slow-speed round bur is acceptable, but stay within 1–1.5 mm of the chamber floor.
- Find the orifice. Mandibular first molars have a mesial canal (often two) and a distal canal; the distal orifice lies distal and slightly buccal to the midline of the floor. Look for the darkest point, a catch with a sharp explorer, or a tiny bleed. Irrigation with 3% hypochlorite and a cotton pellet makes a bleeding point obvious.
- Negotiate. Pre-curve a size 06 or 08 stainless steel file, place EDTA gel, and use watch-winding with light apical pressure, no rotation, in 0.5-mm increments, irrigating and recapitulating as you go.
- Measure. Without an apex locator, place the file, fix a haemostat as a stop, and take a paralleling radiograph, reading the tip against the radiographic apex and subtracting 0.5–1.0 mm. Confirm the length with a paper point and take a second angled film if in doubt.
Stop and refer or extract if: (a) no file passes the coronal third after about 20–30 minutes of careful effort; (b) you cannot establish a working length you trust to within 1 mm; (c) you detect a ledge, perforation or separated file, or the patient's comfort or the appointment time is exhausted. An under-instrumented canal packed with gutta-percha at an estimated length is worse than an extraction and a planned prosthesis.
3. Justify single-visit versus multiple-visit treatment here, and specify the definitive restoration you would place given that the patient cannot return for two weeks.
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Single visit, if and only if you can complete it. The decisive factors are logistical rather than biological: three hours each way, no return within two weeks, a tooth already open to the mouth, and the consequences of a lost temporary (reinfection, flare-up, and an emergency she cannot attend). Evidence shows no meaningful difference in outcome between single- and multiple-visit treatment of irreversible pulpitis when the canal is properly cleaned, so the safer local choice is to finish the job.
The plan must be conditional. If working length cannot be obtained, or the canal cannot be prepared to at least size 25 with copious 3% hypochlorite, place calcium hydroxide, seal with a well-adapted temporary (IRM, or glass ionomer over a cotton pellet), prescribe analgesia, and refer to a centre with an apex locator or CBCT rather than obturating at a guessed length.
Restoration. The distal wall and marginal ridge are gone, so the tooth needs a bacteria-tight seal and a core, but a large unsupported composite built up over a just-treated pulp will not survive occlusal load. Plan cuspal coverage. If laboratory work cannot be arranged before she leaves the province, place a bonded composite or amalgam core with a well-sealed interim restoration, and record in the notes that a definitive cuspal-coverage restoration is due within a few weeks. Explain to her that the root treatment is finished but the tooth is not finished, and give her a written date.