Rothwell and Boyd (2008) evaluated hearing thresholds and amalgam dental fillings across 39 non-smoking women, ages 40 to 45 years. When non-amalgam fillings were used, there was no correlation between fillings and hearing thresholds. However, in those with amalgam fillings, each additional amalgam filling was associated with a 2.4 dB decline in hearing threshold.
Tambs et al (2003)determined that much of age-related hearing loss can be accounted for by noise exposure, ear infections, head injury and gender, yet the remaining portion was possibly due to environmental toxins. Rothwell and Boyd suggest that perhaps the use of amalgam fillings and the well known ototoxic effects of amalgam may be a component of what is typically considered to be age-related hearing loss.
The ongoing trend to use composites and other non-mercury containing dental filling materials is encouraged.