Zinc poisoning from excessive denture fixative use masquerading as myelopolyneuropathy and hypocupraemia

Abstract

A 50-year-old man presented with a four-year history of unsteadiness, with recent falls and tingling in his fingers. Neurological examination found an ataxic gait, with a positive Romberg's sign. There was distal wasting and weakness in all four limbs and impaired co-ordination, with pseudoathetosis in the arms. Initial investigations showed a normochromic, normocytic anaemia, leucopenia, neutropenia and a low vitamin B 12 (172 ng/L). Treatment with intramuscular cobalamin injections showed no clinical improvement. Further investigations showed an undetectable caeruloplasmin (,0.085 g/L), a very low serum copper (1.1 mmol/L) and a markedly raised serum zinc concentration (36.2 mmol/L). On detailed questioning it became apparent that he had ill-fitting dentures requiring excessive use of denture fixative with high zinc content. The patient was switched to a non-zinc containing denture fixative and commenced copper supplementation. Although within three months the bone marrow suppression had resolved, there was no clinical improvement in neurological presentation. Questioning a patient about their denture fixative usage and checking if zinc is an ingredient may be considered during an investigation for myelopolyneuropathy when vitamin B 12 deficiency is not a cause.

Awareness of zinc toxicity in denture adhesives among dental practitioners in Puducherry - A cross-sectional study

“…[4][5][6][7] The recovery from hypocupremia with copper replacement therapy or withdrawal of zinc-based denture adhesives appears to be controversial. [8] A literature review revealed that there are very limited data regarding denture adhesives being a potential source for zinc toxicity in dental journals, whereas many case reports and cohorts [1,2,5,[9][10][11] on neurologic and blood abnormalities of denture adhesives were found in the field of neurology. This study was planned to assess the awareness of dentist regarding the effects of zinc toxicity since the consequences of long-term overuse are serious.…”