Severely resorbed mandible, long-standing dentures and a request for implants
A 66-year-old woman who has been edentulous for 15 years attends with 11-year-old complete dentures. The mandible is severely resorbed with a knife-edge anterior ridge and mobile tissue, and the lower denture dislodges when she speaks. The upper denture is retentive and acceptable to her. She has type 2 diabetes with HbA1c 8.4%, smokes 12 cigarettes daily, and has taken alendronate 70 mg weekly for six years for osteoporosis. She has heard that two implants hold a lower denture like a nail and asks for them to be placed at this visit. She has no radiographs and no records, and has not seen a dentist since the dentures were made.
1. She wants implants today. What is your assessment and sequencing, and which findings could change your recommendation?
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The complaint is a loose lower denture, not a missing implant, and the two are not the same diagnosis. Eleven-year-old dentures on a ridge that has resorbed for 15 years will have lost their border seal, their extensions and their occlusal vertical dimension, and the mobile tissue suggests denture trauma or resorption underneath. A well-made new denture may solve most of the complaint, and it is also the diagnostic tool I need: it establishes the tooth position, the neutral zone, the lip support and the space available for attachments.
Sequence:
- Full examination, OPG and, if implants are being considered, cone-beam CT to measure bone height, width and the position of the mental foramina.
- Optimise diabetes with the physician, aiming for HbA1c below roughly 7 to 8% before surgery, and offer smoking cessation.
- Obtain physician advice on the six-year alendronate history and document the discussion.
- Make new complete dentures, treat any denture stomatitis, and review function.
- Reassess the complaint at review; if instability persists, proceed to a two-implant overdenture with informed consent about the added risks.
The recommendation would change if the bone height in the canine region is inadequate without grafting, if HbA1c stays above 9%, if she cannot attend for follow-up, or if she prefers to avoid surgery once the risks are explained.
2. How do you counsel her about the bisphosphonate and the smoking, and what would you do if she declines to stop smoking?
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Both points need to be put in absolute terms rather than as vague warnings, because she has to weigh them.
Alendronate. Oral bisphosphonate use for six years carries a low but real risk of medication-related osteonecrosis of the jaw after bone surgery, generally estimated at well under 0.1% for oral therapy, and higher with longer duration, corticosteroids, diabetes and smoking. I would explain that implants are not contraindicated but that the risk is not zero, obtain the physician's written opinion, and avoid stopping the drug on my own authority, since any drug holiday is a decision for the physician and is not routinely recommended for oral therapy. Consent should record that this was discussed.
Smoking. Smoking roughly doubles implant failure and increases peri-implantitis, so cessation for at least one to two weeks before and eight weeks after surgery is the advice, with referral to a cessation service.
If she declines to stop, I would not simply refuse care. I would document informed consent, explain that the risk is higher, and discuss alternatives: a single midline implant with a simpler surgical site, or optimised conventional dentures with no surgery at all. Respecting her choice while making the trade-off explicit is better than an ultimatum, and a new denture is a reasonable outcome if she chooses it.
3. If she proceeds with a two-implant mandibular overdenture, which prosthodontic design decisions matter most given her ridge, and how would you present the single midline implant option?
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Design must compensate for a knife-edge, mobile anterior ridge and a resorbed posterior mandible.
- Implant position: two implants in the canine region, splinted or unsplinted, placed to allow a common path of insertion and to sit within the neutral zone.
- Attachment: resilient stud or locator-type attachments reduce tipping forces on the implants; a rigid bar is reserved for cases needing splinting or where hygiene access allows.
- Denture base: maximum extension to the retromolar pad and buccal shelf for support and border seal, because the implants provide retention and the ridge provides support. A metal-reinforced or high-impact acrylic base resists fracture in a thin denture.
- Occlusion: balanced or lingualised contacts, with the occlusal plane corrected to a proper vertical dimension so that tipping forces are minimised.
- Tissue surface: relieved over mobile tissue, with hygiene access around attachments built in.
On the single midline implant, I would present it honestly: it is a simpler, cheaper operation with good evidence for improved retention and satisfaction compared with a conventional denture, but it provides less stability against lateral and rotational movement and does not protect the posterior ridge from resorption. Two implants remain the minimum standard for an overdenture, and four would be offered only if bone and budget permit. The choice should reflect her anatomy, her dexterity and her willingness to attend for maintenance.