Millions of adults wear clear aligners and orthodontic appliances, trusting these devices are biocompatible. New evidence reveals these dental polymers continuously shed microplastic particles that infiltrate immune cells and alter their fundamental behavior, potentially compromising both oral and systemic health defense mechanisms.
This investigation examined six clinical orthodontic materials, including popular brands like Invisalign and newer direct-printed resins. When exposed to artificial saliva conditions, all materials released measurable microplastic particles within one week. Flow cytometry analysis revealed significant particle counts, while microscopy showed these fragments readily penetrate macrophages—the immune cells responsible for clearing foreign matter and maintaining tissue homeostasis. Once internalized, the microplastics disrupted normal macrophage differentiation patterns and altered cellular function.
The implications extend beyond simple foreign body reactions. Macrophages serve as frontline defenders throughout the body, from lung tissue to liver function. If orthodontic microplastics can reprogram these cells in the oral cavity, similar disruption may occur systemically as particles migrate through lymphatic and circulatory systems. This represents a largely unexplored intersection of materials science and immunotoxicology. While orthodontic treatment provides clear benefits, this research suggests the dental industry must urgently evaluate polymer compositions and develop safer alternatives. The findings are particularly relevant given the explosive growth in adult orthodontic treatment and the extended wear periods these devices require. Long-term studies tracking immune function in orthodontic patients appear warranted.