Evaluation of amalgam-related retinal neurotoxicity with optical coherence tomography findings

Abstract

Purpose: To evaluate the neurotoxic effect of amalgam dental fillings on plasma mercury (Hg) levels and retino-choroidal layers measured by spectral domain optical coherence tomography (SD-OCT).

Materials/methods: Study participants included 56 cases with amalgam dental fillings and 44 healthy controls. All participants were examined in terms of detailed ophthalmic examination, oral examination, and body mass index (BMI). The measurement of retinal layers and choroid was performed using SD-OCT. Venous blood samples were collected and blood Hg levels were measured using cold vapor atomic absorption spectrometric analysis. Correlations between SD-OCT measurement results and blood Hg levels were analyzed.

Results: There were no differences between groups in terms of age, sex, or BMI. The mean blood Hg level was 2.76 ± 1.21 µg/L in the amalgam group and 2.06 ± 1.15 µg/L in the control group ( p = 0.04). The Hg/BMI ratio was 0.12 ± 0.06 kg/m² in the amalgam group and 0.09 ± 0.05 kg/m² in the control group ( p = 0.01). Reduced volumes of ganglion cell layer and inner plexiform layer were observed in the amalgam group when compared with the control group ( p < 0.05).

Conclusion: Amalgam dental fillings can cause retinal neurotoxicity. SD-OCT can be useful for evaluating amalgam-related retinal neurotoxicity.

Keywords: Amalgam toxicity; optical coherence tomography; retinal neurotoxicity.