W.T. Sweeney

Dental research at the national bureau of standards in relation to orthodontia

George Colby Paffenbarger was a man of considerable insight. Nearing the end of his life as a result of prostate cancer, he perceived a need to educate the dental profession and the public about the enormous benefits to dentistry and public health that were being wrought through the cooperative research of the American Dental Association (ADA) and the National Bureau of Standards. Tax dollars, allocations from ADA dues, and funding from the National Institute of Dental Research were being used to support this work, and it was important for everyone to know that this investment was yielding benefits which far exceeded costs. Elsewhere, an oversupply of graduating practitioners and a reduced demand for dental care was leading to the closing of some dental schools and an attendant pressure to reduce all sources of funding for dental research. What George Paffenbarger saw, and others did not, was the continued evolution of (then unappreciated) dramatic benefits from dental research, even as the primary emphasis for research began to shift away from treatments for caries (the incidence of which had already declined) to treatments for other oral diseases and conditions. Paffenbarger’s solution to this problem was to publish a paper [1] that would place the ADA/ NBS dental research program into a clear and succinct context. Paffenbarger undertook this project in collaboration with John A. Tesk and W. E. Brown at NBS. Together, they documented the development of modern dental materials research, beginning with the inception of a dental research program at NBS in 1919. The beginning can be traced to a request by the U.S. Army to develop a bid specification for the purchase of dental amalgam. That effort, headed and championed by Dr. Wilmer Souder, focused on the properties of amalgams, including their compositions, dimensional changes on setting, compressive strengths, and flow characteristics [2]. That work led to the collaboration between NBS and the Weinstein Research Laboratory to measure the physical properties of the whole range of materials being used by dentists, for which the literature of the day was rather scant and often controversial [3]. The impact of that eight-year study is credited with the development of the cooperative program of the ADA and NBS, which continues to this day. The review by Paffenbarger, Tesk, and Brown paints a picture of a remarkable and far-reaching program that touches on every aspect of dentistry and, hence, public health. The thrust of the program was not simply the measurement of properties or even the development of standards and certification programs. Dental professionals and the public needed to be informed about the significance of the results, particularly with respect to self-serving promotions of products that had been propagated unchecked early in the century. “Aside from probable deceptive claims (for the exploitation of dental materials) exposed in the individual surveys, reports were published by the Association at NBS showing the fraudulent nature of some of the deceptions.” [1] Dental practices were also an important part of the program. As the ADA/NBS program began to understand more about the physical and chemical properties of amalgams, the influence of impurities and contaminants on the degradation of restorations also began to be understood. In one case, the practice of dentists mulling the amalgam mix in the palms of their hands was found to add moisture and sodium chloride to the mix, which subsequently led to severe corroding of zinc-bearing amalgams [4]. Fig. 1. George C. Paffenbarger.