Orthodontic braces are a common medical device used by millions globally to correct dental misalignment and improve oral function. These appliances typically remain in the mouth for one to three years, leading some patients to question the long-term safety of the materials involved. Concerns often center on whether the metals and plastics used in the mouth could pose a risk to overall health, specifically regarding cancer development. This article addresses these concerns by examining the scientific evidence and regulatory standards governing orthodontic materials.
The Scientific Consensus on Orthodontic Safety
Large-scale epidemiological studies and systematic reviews confirm that the use of braces does not increase a patient’s risk of developing cancer. Research has investigated this potential link, focusing on the release of trace metals, and consistently found no correlation.
The scientific community has reviewed patient data, tracking health outcomes over many years. These meta-analyses looked for statistical associations between receiving orthodontic care and the subsequent diagnosis of various cancers. No evidence suggests that the minute amounts of substances released from fixed appliances lead to carcinogenesis.
Although certain metals are classified as carcinogenic, the exposure level from orthodontic devices is insignificant. Studies comparing metal ion concentrations in the oral environment of patients with and without braces established that the levels are exceptionally low. This evidence supports the safety of standard orthodontic procedures regarding cancer risk.
Components of Braces and Biocompatibility
Orthodontic appliances are composed of materials chosen for their mechanical properties and ability to integrate safely with the human body. Biocompatibility ensures a material performs its function without causing adverse biological reactions. Metallic components, especially the alloys used for brackets and archwires, are the most scrutinized.
The most common metal alloys include stainless steel, nickel-titanium (NiTi), and titanium-molybdenum. Stainless steel is valued for strength, while NiTi is used for its superelasticity and shape memory to move teeth efficiently. These metals can corrode in the oral environment, resulting in the release of trace metal ions.
Nickel, a component in NiTi and stainless steel, is classified as a human carcinogen at high exposure levels. However, the amount of nickel released from braces is far below the harmful threshold. The oral fluid concentrations of leached ions remain extremely low, often orders of magnitude less than permissible levels established for drinking water.
Non-metallic components, such as plastic resins for aesthetic brackets or composite adhesives, also undergo rigorous testing. These materials can release small amounts of monomers or organic byproducts during the initial curing phase or over time. Like the metal ions, these trace amounts are considered negligible and have not been linked to cancer risk in clinical studies.
Regulatory Oversight and Material Testing
To ensure the safety of dental materials, manufacturers must adhere to stringent regulatory standards before products reach the market. In the United States, the Food and Drug Administration (FDA) classifies and governs orthodontic devices as medical devices. Traditional appliances, such as brackets and wires, typically fall under Class I, requiring adherence to general controls that ensure safety and effectiveness.
Newer or more complex devices, like certain clear aligners, may be classified as Class II. This necessitates a rigorous Premarket Notification (510(k)) clearance process. This process requires manufacturers to demonstrate that their product is substantially equivalent in safety and performance to a legally marketed predicate device. This regulatory oversight ensures materials meet high standards of patient protection.
Materials must pass standardized biocompatibility testing, including assessments for cytotoxicity, or the potential to damage cells. Testing also focuses on corrosion resistance, simulating oral conditions to measure the rate and quantity of ion release. These evaluations align with international standards, such as those set by the International Organization for Standardization (ISO), confirming the materials are stable and safe for prolonged oral contact.