LETTERS FROM OUR READERS

To: Editor, The Angle Orthodontist, RE: A Plea for Agreement

Standardization is an essential ingredient for technological progress. Some examples include the QWERTY keyboard that was agreed on for the first typewriters and that survives on computer keyboards. In the 19th century, agreement on the width of rail tracks ended years of chaos in transportation and permitted the development of transcontinental rail. From the rate of tape transport in VCRs to the speed of processing computer bytes, standardization has promoted advances in technical applications.

When Edward H. Angle introduced the edgewise bracket, he adopted 0.022 inches as the standard size for brackets. That size slot remained uncontested until the middle of this century, when some orthodontists promoted an 0.018-inch slot. Angle used gold arch wires, and the 0.022-inch by 0.028-inch slot provided rigidity when that was needed. Advances in metallurgy, particularly in the development of stainless steel alloys, allowed for rigidity with a smaller wire than Angle used. The 0.018-inch slot became a rational alternative.

In the past decade, new alloys have been developed that generate light forces even with larger wires. Titanium alloy wires and braided wires offer very light forces even when the slot is filled.

Currently in the United States, a slight majority of orthodontists use the 0.022-inch slot, whereas in Europe, a majority use the 0.018-inch slot. I believe that the adoption of a single slot size would be an important advance in orthodontics. The most important reason is to provide seamless treatment in transfer cases. Over 15% of Americans relocate each year. Some of these moves are within the same community, but it is safe to estimate that approximately l0% of our orthodontic patients will move out of our area each year, requiring the continuation of treatment in another office. The dichotomy in slot size can make it necessary to change the brackets to obtain the bracket size that the new orthodontist uses. This procedure has unnecessary potential side effects and inevitably prolongs treatment.

An 0.020-inch slot would be a reasonable compromise that would allow both orthodontic groups to adapt to the new size with minimal alterations in their arch wire selection.

Orthodontic manufacturers have expressed interest in this possible change. They note such a change would help them, as they would require less inventory and manufacturing equipment. Conceivably, these savings would result in lower prices. They indicated that the change can occur only if the heads of the nation's graduate orthodontic departments support the idea. They reason that most orthodontists use the same size bracket in practice that they used during their training.

Armed with this information, I developed a questionnaire and cover letter to send to the chairs of the nation's orthodontic departments. Frankly, I thought it would be a virtual “slam dunk”: make a minor change in your arch wire progression in exchange for increased efficiency in time and materials in handling transfer cases.

I was shocked by the responses. The raw numbers were 12 in favor of the change and 17 opposed to a single bracket size. The comments surprised and disappointed me. There was virtually no mention of the advantages to the public. Resistance to change and unwillingness to compromise were the themes of the comments.

I am forwarding the results to the Orthodontics Manufacturers Association (OMA) as I promised, without much hope that we will have a 0.020-inch standardized bracket.

As I write this with some sadness, another possibility occurs to me. If the overwhelming majority of wet-gloved orthodontists—the ones who send out transfer cases and take in several each year—supported the idea, the OMA would hear our call for agreement on this subject.

The history of progress in applied technology suggests it is inevitable that there will be agreement on this one day. When that occurs, there could be a significant increase in product development because of the economies of scale. A new product that will serve only half of the nation's orthodontists is less likely to go to market than one that would serve all orthodontists. In the meantime, clinical orthodontists will persevere to get the best results possible despite a significant obstacle that could be removed, but only by agreement from a large majority of us.

It is amazing how large an abyss 0.002 inches can be. It appears that the thickness of a human hair is as big an obstacle as an unscalable wall.