Anyone who was ever called Metal Mouth, Brace Face, or Railroad Tracks in ninth grade can tell you that conventional metal braces don't exactly enhance your appearance. There's no denying that invisible braces look a lot better than conventional metal braces. And that's the way they're marketed. But how safe and effective are they?
Are Invisible Braces Safer than Conventional Metal Braces?
Safety is never absolute for any product. In this case, it makes more sense to consider the potential harm that might be caused by invisible braces and compare it to the potential harm that might be caused by conventional ones.
Concerns about the safety of invisible braces center on the plastic material from which they're constructed. What sometimes gets lost in this discussion is that both conventional and invisible braces require the long-term installation of foreign materials in your mouth.
What Are Invisible Braces Made Of?
Modern American invisible braces do not contain Bisphenol-A (BPA) or phthalate plasticizers. They're made from medical-grade thermoplastic polyurethane with an integrated elastomer that governs the braces relative flexibility and rigidity. Commonly used materials include methylene diphenyl diisocyanate (MID) and 1.6-hexanediol (HD).
Each manufacturer adds proprietary materials to their braces in a quest to make them as non-reactive, "hypo-allergenic," and effective as possible. Less-commonly used materials include polyethylene terephthalate glycol (PeT-G), polypropylene (PP), polycarbonate (PC), thermoplastic polyurethanes (TPU), and ethylene vinyl acetate (EVA). Since manufacturers closely guard their unique material mixes, it's rarely possible to discover every single additive that's used in a given set of invisible braces.
What Are the Risks Associated with Invisible Braces?
The Food & Drug Administration groups medical devices into three classes, with Class I indicating the lowest threat to patients and Class III indicating the highest risk. Invisible braces are Class II medical devices and have been approved by the FDA.
There has never been a reported case of a death or a serious medical reaction from the use of invisible braces. There have been reports of adverse reactions, but these are very few in number when considered against the millions of people who have used invisible braces without any problem. One study found only 175 reports of adverse events and reactions (AERs) were submitted to the FDA in a five-year period. Of these, the most common issues were allergic reactions (18.3% of all reported AERs) and anaphylactic reactions (11.4% of all reported AERs). These may be due to the presence of MID, which is an allergen and a sensitizer in some people. Other reported reactions included angioedema, mouth and lip lesions, hives, nausea, gastrointestinal issues, muscle cramps, coughing, headache, fever and cardiac issues. It should be noted that all of these reports are merely claims that a person developed a particular health issue following the use of invisible braces. They do not prove that those health issues were actually caused by the braces.
What Are the Risks of Conventional Metal Braces?
When considering these health effects, it's worthwhile to compare them to the effects of conventional metal braces. The materials used to make them release iron, chromium, and nickel ions as they decay. Nickel in particular has been cited as the probable cause of many of the allergic reactions that are linked to conventional braces.
Another commonly reported adverse health effect from conventional braces is the laceration of the gums, lips and tongue. These injuries occur especially people wearing metal braces are hit in the mouth while playing sports or even while engaging in less vigorous physical activities. While statistics on the frequency of such injuries are hard to come by, they appear to occur far more often on a per-patient basis than do injuries or illnesses associated with invisible braces. In fact, the comparative safety of invisible braces in this regard is one of their key advantages.
What's the Bottom Line of the Safety of Invisible Braces?
When the frequency and severity of allergic reactions and traumatic injuries associated with conventional braces and invisible braces are compared, invisible braces may actually be less dangerous to people's health than conventional ones.
Are Invisible Braces More Effective than Conventional Braces?
What about effectiveness? How well do invisible braces work?
Here, the evidence is more ambiguous. While conventional braces are literally hard-wired into patients' mouths, invisible braces are removable appliances that require patent compliance to work properly. They have to be worn 20 to 22 hours a day to be effective. Thus patient motivation and discipline are key factors in the effectiveness of invisible braces. This can be a particular problem for teens, who may not be as committed to orthodontia as their parents. To address this issue, at least one invisible braces manufacturer offers a "compliance indicator" which parents can examine to determine of their children have been wearing the braces for the prescribed time.
Another factor that affects how well invisible braces work is how they are fitted and prescribed. Many dental clinics and manufacturers of invisible braces provide them to customers they've never actually seen. Customers who can't or don't want to see a dentist or an orthodontist can have dental impression kits sent to them by mail, along with instructions for how to photograph their own mouths. The dental impressions and photos are then sent to a dentist or orthodontist who reviews them and, if appropriate, prescribes and orders the invisible braces.
Are Invisible Braces Prescribed by Mail Effective?
Opinions about this process are divided. Those who favor it point out that it brings orthodontia to people who are unable to physically visit a practitioner's office. They also suggest there may be some cost savings involved. Those who oppose it point to the risks involved in prescribing a dental appliance for someone whose mouth a dentist has never actually seen. They contend that molds and photos can't spot issues relating to how the lower and upper teeth come together or assess the health of the gums and jaw joints. They argue that for braces to be effective, regular in-person patient monitoring is needed to determine how close the patient's teeth are to each other and how well the teeth are fitting together. As one orthodontist put it, "There is a legitimate reason that orthodontists acquire seven years of post-college education to become experts at the science and art of orthodontics."
What's the Bottom Line on the Effectiveness of Invisible Braces?
What about the effectiveness of invisible braces that are properly fitted, prescribed, worn, and monitored? Here, the evidence is inconclusive. Researchers with the US National Library of Medicine and the National Institutes of Health reviewed a number of studies on this question. They found that treatment with invisible braces "aligns and levels the arches; it is effective in controlling anterior intrusion but not anterior extrusion; it is effective in controlling posterior buccolingual inclination but not anterior buccolingual inclination; it is effective in controlling upper molar bodily movements of about 1.5 mm; and it is not effective in controlling rotation of rounded teeth in particular."
Again, it's important to remember that treatment with conventional braces is not 100% effective at remedying orthodontic issues either. So the question of the comparative effectiveness of invisible braces comes down to a case-by-case answer governed by variables such as patient compliance and the nature of the problem to be remedied.