Crown-root-treated 46 with a periapical lesion in a bruxist who cannot afford an implant
A 52-year-old joiner attends for a second opinion on his lower right first molar. The tooth has a porcelain-fused-to-metal crown and was root-treated twelve years ago; it has never been painful since. He has just changed jobs and cannot afford an implant. His previous dentist advised extraction because of a 6 mm periapical radiolucency seen on a bitewing, and offered a three-unit bridge from 45 to 47. On examination 46 is asymptomatic, has 3 mm of visible crown height, grade I mobility, probing depths of 3–4 mm with no bleeding, and no sinus. The crown margin is supragingival buccally but subgingival interproximally. 45 and 47 are sound and minimally restored. He grinds his teeth at night, has worn through two night guards in five years, has a maximal opening of 42 mm and palpable masseter hypertrophy. There is no history of swelling or antibiotic use. He asks whether the tooth can be saved.
1. Compare the reasonable options for 46 and state what information you need before recommending one.
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The options
- Do nothing and monitor. An asymptomatic, previously treated tooth with a stable periapical lesion in a patient with no symptoms can sometimes simply be reviewed; lesions may be scar tissue. This is defensible only if the lesion is genuinely unchanged on comparison and the patient accepts review.
- Nonsurgical retreatment. The biological argument is that the apical seal or an untreated canal is the source of the lesion. Retreatment removes the coronal restoration and, almost certainly, a post. It is the most conservative option but carries a real risk of root fracture or perforation during post removal, and success in a molar with a post and a large lesion is lower than in a first-time root canal treatment.
- Apical surgery. Reasonable where the coronal restoration and post are sound and the root filling cannot be improved, and where the root end can be resected without compromising the furcation. It needs a good crown-root ratio and a cooperative patient.
- Extraction with a three-unit bridge 45–46–47. Predictable but destructive: it requires preparing two sound teeth and creates a hygienically demanding pontic in a patient who grinds.
- Extraction with a single implant or a removable partial denture. The implant is the preferred replacement on biological grounds but he has said he cannot afford it.
Information I need
- A periapical radiograph and, ideally, cone-beam CT: post length and width, remaining dentine thickness, furcation involvement, presence of an untreated or missed canal, a lateral perforation or a vertical root fracture.
- Previous radiographs for comparison to see whether the lesion is changing.
- Sensibility and percussion tests of 45 and 47, and an assessment of the occlusion and wear pattern.
- His priorities, budget and willingness to attend for retreatment.
2. He says he would rather have it out and a bridge. What are the specific considerations for a 45–46–47 bridge here, and how would you present the choice?
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Considerations specific to this patient
- Tooth destruction: 45 and 47 are sound and minimally restored. Preparing them converts two intact teeth into crowned teeth with a lifetime of maintenance, and the long-term survival of the bridge is governed by the weakest abutment, not by the molar that was lost.
- Bruxism: worn-through guards in five years and masseter hypertrophy indicate heavy parafunctional loading. Bridges in bruxists show higher rates of ceramic fracture, decementation and abutment failure; a bridge increases the number of units at risk.
- Pontic site hygiene: the ridge under 46 will resorb, leaving a cleansable gap that still demands daily interdental cleaning; a non-cleansable pontic risks abutment caries and periodontal breakdown.
- Stressing the abutments: he is a joiner with a probable high bite force and the molar is the 'keystone' tooth; loading two premolar-sized abutments in its place is biomechanically demanding, unlike an implant-supported single crown.
How I would present it I would draw the three options - retreatment with a new crown, extraction and bridge, extraction and implant - as three columns of risk, cost, number of visits and expected lifespan, and be honest that the bridge is a reasonable, predictable choice but that it commits two healthy teeth and may need replacing. I would make clear that extraction is irreversible and that a CBCT first would tell us whether retreatment is realistic; if it shows a vertical root fracture, the decision makes itself. I would also point out that whatever we choose, the bruxism needs managing with a hard occlusal splint and review of the guards.
3. What is the role of his bruxism in the long-term plan, and how would it change your decision if the CBCT showed a vertical root fracture of the mesial root?
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Bruxism in the long-term plan Sleep bruxism is not curable, so it must be managed and its consequences designed around.
- A hard, well-fitting occlusal splint rather than a soft one, with regular review; the fact that he has worn through two guards suggests they were either soft or poorly adjusted, and also that his loading is severe.
- Occlusal scheme: whatever restoration is chosen should have a flat, shallow anatomy with broad contacts and no steep guiding inclines on the restored unit.
- Material choice: monolithic zirconia or a full-coverage metal occlusal surface is more fracture-resistant than layered ceramic on a molar in a heavy grinder.
- Maintenance: short recall intervals for the splint, the restoration and the remaining teeth, and a conversation about sleep, stress and possible referral if there is suspicion of sleep apnoea.
- Prognosis counselling: any restoration will need replacement sooner than in a non-bruxist, and this should be said before treatment, not afterwards.
If the CBCT shows a vertical root fracture of the mesial root The decision is made: a fractured root cannot be saved, retreatment and apical surgery are both futile, and the tooth should be extracted. The judgement then shifts to what happens next. I would extract atraumatically and consider whether the mesial root can be removed separately to preserve the buccal plate, plan ridge preservation if an implant is a future possibility, and present the bridge and the removable option again - while noting that a two-unit cantilever or a resin-bonded design might be less destructive than a conventional three-unit bridge. His bruxism still favours avoiding extra abutment preparations if a single implant later becomes affordable.