Prosthodontics & Occlusion · patient case question
Which component of a denture adhesive has been associated with neurological toxicity in heavy long-term users?
Patient case: “I Want Teeth That Don't Come Out”
Patient: 64-year-old female
Chief Complaint: “I'm done with these plates. I want teeth that don't come out.”
Background: Wearing maxillary and mandibular removable partial dentures for eight years. Good general health, non-smoker, financially able to proceed.
Medications: Atorvastatin
Vital Signs: BP 126/78 mmHg · HR 72 bpm · RR 16 · T 98.4°F
Findings: Maxilla: first molars and canines present in both quadrants. Mandible: second molars and some premolars present. Remaining teeth are periodontally sound with good bone support. Adequate ridge volume in the edentulous spans on CBCT. No parafunction.
Show answer and explanation
Correct answer: D. Zinc
- A. Methylcellulose and carboxymethylcellulose are the standard adhesive polymers and are inert.
- B. Copper is the mineral that becomes DEFICIENT as a consequence — it is not an adhesive ingredient.
- C. Glycerin is a humectant and carrier with no neurotoxicity.
- D. CORRECT. ZINC. Some denture adhesives contained zinc salts to improve adhesion, and patients who used very large quantities daily over long periods absorbed enough zinc to cause the problem. Excess zinc interferes with COPPER absorption, and the resulting copper deficiency produces a MYELONEUROPATHY: sensory ataxia, paraesthesia, limb weakness and gait disturbance, sometimes with anaemia and neutropenia. Major manufacturers reformulated to zinc-free products after this was recognised.
Note: The clinical clue is a denture wearer using several tubes of adhesive per week with unexplained neurological symptoms. The underlying issue is nearly always an ill-fitting denture — the correct treatment is to reline or remake the prosthesis, not to switch adhesives.
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