Claims of treatment (appliance) superiority must be analyzed rationally and dispassionately. Otherwise, scientific truth might be lost in the smoke of heated argument without resolution.
To assess the evidence for or against the claims of superiority made by self-ligating bracket (SLB) manufacturers (and advocates), we asked: are there peer-reviewed data to support these claims? Are the data independently confirmed? We then commented on evidence strength based on the available answers. Briefly:
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Do SLBs “grow” buccal bone? Evidence showing whether this phenomenon occurs, or does not occur, in response to treatment with SLBs is weak and not peer-reviewed, and should be interpreted with caution. Additional well-designed peer-reviewed studies are needed to answer this question. These are facts.
Currently, it is inappropriate for SLB manufacturers to make this claim.
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Is SLB expansion comparable with RME plus fixed appliances? Although the thesis making this comparison is often cited as published in a peer-reviewed journal, it was not peer-reviewed. Our assertion is true: “no peer-reviewed scientific evidence supports this claim.”
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Is SLB expansion stable in the long term? You’ve taken this sentence out of context: “there are treatments which may be effective, but for which a high level of evidence may not be found.” Evidence for postretention stability after RME and fixed appliances is not the “highest” because there are no randomized clinical trials involving this intervention. Evidence for long-term stability of SLB expansion is, at present, anecdotal.
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Are SLBs more effective? The meta-analysis finding of 1.5° less mandibular incisor proclination for SLB treatment was questioned in a recent AJO-DO “Reader’s forum.” The authors of the meta-analysis responded by stating that “we do not consider our conclusions to be robust, and they could be influenced greatly by just a couple of additional, well-conducted trials.” We agree. Additional well-designed studies are needed.
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Do SLBs reduce friction? We did not imply that in-vitro results on friction are “contrived.” Dr Burrows’ evaluation of Thorstenson and Kusy’s work has shed light on data from in-vitro friction studies. Our statement, “At this time, the exact role of frictional forces opposing motion of a bracket along an archwire in vivo is not clear, and the relationship between bracket-archwire friction and tooth movement remains to be elucidated,” is accurate and fair.
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Are SLBs less painful? We did not “downplay” information on pain perception. We pointed out study weaknesses. Our statement, “At this time, additional studies are needed to fairly and fully answer this claim,” is accurate and unbiased.
We would never suggest that clinical judgment is “based exclusively on systematic scientific evidence.” Evidence-based practice requires equal weight for 3 domains: the best available scientific evidence, the orthodontist’s clinical skills and judgment, and each patient’s needs and preferences. In my practice, clinical skill and judgment with SLB systems result in excellent outcomes for my patients (my proficiency bias notwithstanding). However, I also take the responsibility to inform my patients that the best available scientific evidence lacks sufficient strength to support 12 of the 14 most notable claims made for these bracket systems.