What are self-ligating braces (brackets)?
Self-ligating brackets feature a sliding gate or door that holds the wire in place, as opposed to the colored elastic ties that are used with traditional braces. The are manufactured and marketed by various orthodontic supply companies. Like traditional brackets, they are available in metal and clear versions.
What advantages have been claimed for self-ligating braces?
- Less chair time each appointment.
- Shorter total treatment time.
- Greater comfort.
- Reduced need for extractions.
- Can eliminate need for expander appliances.
- More hygienic.
Why evaluate treatment from an evidence-based standpoint?
Evidence-based health care advances two goals: 1) that scientific evidence is used to determine what treatments are best for a given condition, and 2) that it is the patients’ right to take part in their own health care decisions from a position of being properly informed. This approach is credited to Archie Cochrane, a British medical researcher who promoted the concepts of proper scientific method in developing and applying health care principles. There are three components to evidence-based care, including what quality scientific evidence tells us, the doctor’s clinical experience and judgment, and the patient’s values and expectations. The doctor and patient should discuss and consider all three components when treatment options and risks exist. For more information on the Cochrane organization, click here.
What does the research say about self-ligating vs. standard brackets?
- http://www.ncbi.nlm.nih.gov/pubmed/27095145 No oral health or comfort advantages were shown.
- http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4299422/ No evidence of less strep mutant (a key oral bacteria) was shown.
- http://www.ncbi.nlm.nih.gov/pubmed/23299650 There was a lack of evidence of greater comfort, less visits, and lower treatment time.
- http://www.ncbi.nlm.nih.gov/pubmed/21875995 Some evidence of reduced chair time per visit, but no evidence of other advantages.
- http://www.ncbi.nlm.nih.gov/pubmed/20685517 Shortened chair time per visit and slightly less forward topping of lower front teeth, no evidence of other advantages.
- http://www.ajodo.org/article/S0889-5406(08)01183-9/abstract No evidence that treatment time is reduced.
- http://www.ajodo.org/article/S0889-5406(14)00088-2/abstract Space closure was not shown to be faster.
I would like to offer option based upon the above-cited research and a bit of logic. First, I’d like to make the point that healthcare practitioners and consumers must be aware that there is a wide range of quality and significance when it comes to scientific studies. Common issues include funding bias (research funded by the company that stands to profit from positive findings), improper study design, poorly chosen statistical analyses, and improper conclusions. Meta-analyses and systematic reviews provide a very high level of scientific inquiry. In the end, bracket choice still comes down to a matter of preference. On the self-ligating bracket positive side, there is some reduction in the amount of time spent on each appointment, but not to a large degree. I personally prefer the versatility of traditional brackets, as they allow me a bit more control of forces applied to individual teeth. The claims of reduced total treatment time, greater comfort, and better hygiene just don’t stand up to quality studies, and I can’t help but wonder what level of evidence these claims are based upon. In addition, in my opinion, the claims of reduced need for extractions and eliminating or reducing the need for expander appliances defy logic. The reason one would use an expander is to gain width in the upper jaw, which is possible in children and teens. When increasing the upper dental “arch” width with braces, you are essentially moving teeth though bone rather than expanding the jaw, and the type of bracket used does not change this reality. On the extraction claim, keep in mind that there are various reasons to extract teeth (click here to see my blog post on this topic) that bracket design can’t resolve. Most importantly, the bone that forms the outer part of the dental sockets can be very thin or even missing, and moving teeth outward comes with the risk of further thinning the bone and causing the bone to recede. These are realities of bone physiology that bracket design cannot change. It all comes back to the three components of evidence-based health care, rather than marketing claims.