A Timeline of Biological Assessments: Our Nonspatial Continuum

Abstract

Much of our dental history is recognized through oral tradition, which has led to myths and misconceptions regarding the efficacy of early restorative agents. Dental biomaterial history has tended to report only certain aspects research in a few textbooks that are expensive and not readily available to the larger dental audience. Our purpose is to provide a detailed peer-reviewed document, which provides a chronological account of our in vitro and in vitro biological continuum. This document follows a published historical chronological timeline of biomaterial testing literature beginning with its little known inception in 1779. Many of the early dental restorative agents evolved due to their anodyne capacity to alleviate tooth pain and provide a modest bacteriostatic capacity. Those that were successful were modified as temporary cavity filling agents and evolved to more permanent fillings. Unfortunately, many of the early agents e.g. antimony, arsenic, asbestos, canthrides, formalin, mercury, mustard, phenol to name a few were toxic to the tooth and supporting periodontal tissues as well as failing to support lost tooth structure. The National Institute of Dental Research required biomaterial testing in the late 1940’s. Even today, the agency permits many pre-1950 agents via the grandfather clause for commercial inclusion and clinical use, while requiring all new post-1958 agents to pass both in-vitro and in vivo testing hurdles. We routinely place restorative agents that infiltrate in graded interphases to interdiffuse into vital enamel, dentine and even cementum by forming a unique biomimetic substrate that mimics the color and opacity of the human tooth. Our biological continuum is still evolving with technologies that will continue to change our clinical future. Our profession has been the global benefactor of dynamic change. Unfortunately, our biomaterials testing status quo is not acceptable as many toxic agents e.g. formalin still remain in our clinics.