September 1, 2011
by Randy Lang, DDS, D. Ortho
It seems that every year an orthodontic company will come out with a new “self-ligating” bracket. Self-ligating orthodontic brackets use a metal clip or door to hold the archwire, whereas conventional orthodontic brackets use ligature wires or elastomeric rings to secure the archwire.
The nice orthodontic salesman and his full-color promotional material will usually claim that his new self-ligating bracket is “the greatest thing since sliced bread”. It will shorten treatment time, reduce the number of appointments, eliminate friction between the bracket and the archwire, be less painful, greatly reduce or eliminate the need for extractions, give broader and more beautiful smiles by “growing” buccal alveolar bone and finally, produce a much superior occlusal result.
One of these brackets is promoted so skillfully by the manufacturer that it has developed an almost “cult-like following”. In fact, when you purchase these brackets, your name can be featured on the manufacturer’s website and you will be advertised as one of their “special doctors” who use their superior brackets.
Now before you throw out all your traditional brackets and exchange them for more expensive self-ligating brackets, you should consider this – almost all of the claims about self-ligating brackets have never been proven in randomized clinical trials with the results published in peer-reviewed scientific journals.
Fortunately, the American Association of Orthodontist’s Council on Scientific Affairs, with the assistance of professors from nine American universities, recently investigated the strength of any research evidence to support the many claims that self-ligating brackets are superior to conventional brackets.1
The following are some of the findings from the study:
“Currently, no peer-reviewed scientific evidence supports that lateral expansion of the dental arch by self-ligating brackets has long-term stability or that it “grows” buccal alveolar bone.”
“The evidence for less friction between archwires and self-ligating brackets presently comes from results found under specific laboratory conditions, which do not fully emulate a clinical setting. In-depth understanding of friction between bracket and archwire in vivo, and its relationship to tooth movement, remains uncertain.”
“A recent systematic review of studies comparing subjective pain experience for treatment with conventional brackets and self-ligating brackets found that neither system has an advantage.”
“Current evidence does not indicate differences between self-ligating brackets and conventional brackets for treatment time, rate of alignment, rate of space closure, final arch dimensions or occlusal outcomes.”
“Chairtime, however, was slightly more efficient with self-ligating brackets because it took 20 seconds less per arch to open or close self-ligating slides compared with removing elastomeric ligatures.”
For those doctors who have already purchased self-ligating brackets based on unproven hype in ads and testimonials, Drs. Kevin O’Brien and Jonathan Sandler offered their condolences in a recently published editorial:2
“It may be that orthodontists who bought the new self-ligating brackets and the philosophy based on the promise that they reduce treatment time and discomfort with less need for extractions, will come to believe that a compelling case of “misselling” (by the orthodontic salesman) has taken place. In retrospect, it is somewhat remarkable that manufacturers can make claims with no apparent checks on the validity or veracity of their statements, while at the same time we struggle for support for scientific research.”
For those currently deciding which type of bracket to buy, I leave with you the following words of wisdom to guide your decision:
“Always remember that in the land of no evidence, claims by the ortho manufacturer are king.”OH
References1. Self-ligating bracket claims. Am J Orthod Dentofacial Orthoop 2010; 138:128-31.2. O’Brien K, Sandler J. In the land of no evidence, is the salesman king? Am J Orthod Dentofacial Orthop 2010; 138.
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