Don’t throw the scientific self-ligation baby out with the commercial bathwater

As an orthodontic researcher, it behooves me to address certain omissions of fact along with the growing errors emanating from the Guest Editorial in the September 2010 issue, “In the land of no evidence, is the salesman king?” Drs O’Brien and Sandler raised a valid issue, that unsubstantiated claims of growing buccal bone in 1 philosophy have been used by a team of evangelistic-styled promulgators to propel sales for a particular manufacturer, especially because these claims do not stand up to the evaluation of peer-reviewed journals. However, I am more alarmed that this might cause orthodontic practitioners and researchers to turn a jaundiced eye to all evidence-based data for self-ligation. As a consequence, self-ligation data appear at risk of being banished to the badlands by O’Brien and Sandler and others.

In their systematic review, Chen et al, clearly identified that the 20-second time reduction created for opening self-ligating brackets was statistically significant, but this improvement in technique was overlooked by O’Brien and Sandler. Furthermore, a thorough examination of the separated studies in the funnel plots (comparison 1.6) 4 showed an additional 10- to 50-second time reduction for closing self-ligating brackets. Unbelievably, this additional time savings was largely disregarded. The correct, total time savings for opening and closing self-ligating brackets is 30 to 70 seconds per arch, and 60 to 140 seconds per patient, and this is highly significant compared with conventional ligatures. In a practice of 50 patients per day, a time savings of 60 to 140 seconds per patient, over 4 days per week, 48 weeks per year, the new difference for clinicians with the application of self-ligating brackets is approximately 2 weeks to 1 month of time reduction each year.

The second advantage of self-ligating brackets, verified by evidence-based data, is a small but statistically significant minimization of mandibular incisor proclination, critical to the patient’s dental stability.

A third basic and often unspoken advantage is the more esthetically appealing, ligature-free self-ligating bracket vis-à-vis the conventional bracket’s lack of esthetics, further limited by decaying elastomeric modules near enamel repeated 20 times per patient. The alternative of 20 metal ligature ties is therefore highly inefficient.

Additionally, in their systematic review, Ehsani et al concluded that there is lower frictional resistance in self-ligating brackets compared with conventionally ligated brackets having small round archwires. These findings were published more than 12 months before the guest editorial of O’Brien and Sandler, but they too were ignored.

To say the least, the blanket comment by O’Brien and Sandler implying in the research, that “this is at a low scientific level and published in journals that are not refereed” and thereby bundling self-ligation studies of resistance to sliding or binding, is unfortunate and inaccurate. The current body of credible self-ligation science should not be confused with unsubstantiated claims made in the marketing literature on orthodontic manufacturers’ Web sites. Greater care should also be used when discounting the evidence by incorporating such absolute written expressions as “no evidence,” “no high-quality studies,” or “none of the claimed advantages” and so on in editorials.

I agree that sophisticated practitioners can now see through questionable commercialism. But be advised: the scientific self-ligation genie is out of the bottle. Caution must be taken not to paint all self-ligation research and application with the same brush stroke of doubt, erroneously creating an illusion of a self-ligation wasteland. It is time to accept the permanent changes of scientific self-ligation investigations.

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Apr 8, 2017 | Posted by in Orthodontics | Comments Off on Don’t throw the scientific self-ligation baby out with the commercial bathwater
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