DENTAL MATERIALS INNOVATION Ideal restorative material Background.—The elimination of dental caries entirely remains an elusive goal for dentistry, so restorations remain the method by which caries damage is handled. The possible innovations in materials science for new directplacement restorative materials were explored to determine the specifications for designing new, better materials. Current Materials and Considerations.—The directplacement restorative materials currently used fall into four classes: amalgam, composites, glass ionomers, and resin ionmers. Amalgam is commonly used worldwide, although the other classes of materials provide better esthetics and may be more desired by patients. These more esthetic materials often are less tolerant of clinical skill and clinical conditions than amalgam. Many concerns arise when considering new restorative materials (Fig). In addition to environment issues such as those that have led to the call for reducing amalgam use are performance, economics, patient expectations, costeffectiveness, health care systems, global challenges in material manufacture and in service delivery. Assessing Candidates.—The aspects most influential in defining performance are crack tolerance, ease of
Fig.—Challenges to innovation. (Courtesy of Rekow ED, Bayne SC, Carvalho RM, et al: What constitutes an ideal dental restorative material? Adv Dent Res 25:18-23, 2013.)
delivery, and clinical performance. In vitro laboratory tests fail to correlate closely with either short-term or longterm clinical performance. The relevance of laboratory tests in accurately predicting clinical performance is questionable. Rather than material costs, the important economic considerations are relative costs, which require a global perspective. The major variable is cost per unit of time, which varies depending on workforce costs and workforce models. With lower salaries and overhead costs, material costs will become more important. Patient expectations and cost-effectiveness should also be considered. Patients expect restorations to function effectively for a very long time. However, it is difficult to predict how long a restoration will last or what the consequences of failure will be at the time the restoration is placed. Therefore the choice of restoration is often left to the dentist, who may be driven by factors other than long-term effectiveness. A cost-effectiveness analysis would be helpful in determining which restorative material is the best choice. The health care system in any situation can profoundly influence whether, when, how, and how quickly alternative restorative materials will become available. Costly materials may not be available to a large segment of the population. When a third-party payer is involved, costs can be passed along in the form of premiums, so the cost of the material may not be especially relevant to its choice as a restorative material. Decisions about new materials can also be driven by wider public considerations. Global challenges can be seen in the manufacture, service delivery, and information transfer of materials. Each country may have protective regulations that require approvals or testing. Regulations may cover packaging and storage, which can sometimes preclude the use of certain materials in some areas. It may be useful in terms of global challenges to establish manufacturing within target countries, which might reduce taxes or production delivery costs and possibly lower the cost of the final product. Knowledge transfer with a local research center may lead to the development of innovative materials using local materials, enhancing the local economy. It should be noted that manufacturers produce products for dentists rather than for
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underserved communities. In response to a call for care in the poorest countries, manufacturers may produce lowcost, less-profitable, or even lower-quality materials targeted to the countries involved. However, local regulations will still be required before these materials can be shipped across borders. Innovation in the delivery of adequate care, especially underserved areas, is needed along with new materials. Dentists need to be engaged in these efforts, but the targeted areas often do not have trained dentists available. An alternative is the training of less-skilled personnel to perform restorative dentistry in these remote or difficult regions. Existing local manufacturers may also provide financial and/or logistical support. All countries should be engaged in the process of creating standardized testing protocols, facilitating the flow of materials across borders, and meeting the needs of underserved areas. Discussion.—Any material developed to meet all the needs of all situations must be available, highly fractureresistant, extremely forgiving of technique and clinician skill, and able to seal and/or heal the remaining tooth
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structure. Many challenges exist to detour the development of a material that meets all these criteria exist. Essentially, the best restorative material is no material, but rather the eradication of caries. Until that occurs, all the economic and other complexities need to be considered carefully in developing innovative materials.
Clinical Significance.—All the stakeholders in new product development need to be involved to ensure that the complex process proceeds as well as possible. Ongoing dialogue is needed to ensure that issues are effectively addressed in the search for materials that will improve tooth longevity worldwide.
Rekow ED, Bayne SC, Carvalho RM, et al: What constitutes an ideal dental restorative material? Adv Dent Res 25:18-23, 2013 Reprints available from ED Rekow, Kings College London, Dental Inst, Central Office, Guy’s Tower, Guy’s Hospital, London SE1 9RT, UK; e-mail:
[email protected]