Spectrometric Study of the Composition of Metal-Containing Orthodontic Appliances: A Cross-Sectional Laboratory Study

BACKGROUND: Recent studies have revealed a rather high prevalence of electric potential differences between metallic inclusions in the oral cavity, including in the presence of metal-containing orthodontic appliances. Due to the lack of precise information in official sources on the composition of structural materials used in orthodontic appliances and the difficulty of theoretical calculation of electrochemical contact potentials, an analysis of the alloy composition of appliances from different manufacturers is necessary.

AIM: To determine and analyze the elemental composition of metal-containing components of modern orthodontic appliances (brackets, archwires, implants) from various manufacturers available on the Russian market using energy-dispersive spectrometry.

METHODS: The sample comprised 16 metal-containing components of domestic and imported orthodontic appliances used in Russia: 8 orthodontic archwires, 5 bracket samples, and 3 orthodontic implants. Elemental analysis was performed using an energy‑dispersive X‑ray detector (EDX) in a dual‑beam scanning electron microscope FEI Helios Nanolab 660 (FEI Company, USA). Quantitative data (element content, weight %) are presented as arithmetic means from three measurement points per sample. Statistical comparison was not performed due to the descriptive nature of the study.

RESULTS: This observational study (n = 16) revealed significant diversity in the composition of widely used metal‑containing orthodontic structures (12 metallic elements, including iron, titanium, chromium). Notably, high nickel (up to 13.9 wt%) and aluminum (up to 10.9 wt%) content was detected for the first time in some implant samples.

CONCLUSION: The problem of controlling the electrochemical activity of metallic orthodontic appliances remains relevant due to the high prevalence of electric potential differences in the oral cavity of patients wearing such devices. Contact between dissimilar metals (brackets, archwires, implants) may trigger electrochemical reactions. The obtained data substantiate the need for a responsible, individualized selection of orthodontic appliances and consideration of their elemental composition during treatment planning. Study limitations: small sample size (n = 16).