Amid I. Ismail, B.D.S., M.P.H., Dr.P.H., Hana Hasson, D.D.S., M.S., Woosung Sohn, D.D.S., Ph.D., Dr.P.H.:
This conference has been called to reach consensus on the diagnosis and management of dental caries throughout life. The mission is to reach conclusions that should define what we can do today in these areas and what we need to know to expand the knowledge base on dental caries. The conference was designed to find answers for six specific questions related to diagnosis of early and advanced carious lesions; indicators of caries risk; methods for primary prevention of dental caries; methods for arresting early carious lesions; clinical decision-making; and what research is needed in diagnosing and managing dental caries. On some of these issues, as the subsequent reviews will show, we have made significant progress in finding answers. But for many of these questions, unfortunately, we still have a long way to go.
This narrative review of dental caries diagnosis and management throughout the millennium is based on information obtained from reports published since 1839 and from 36 textbooks on caries diagnosis and management published since the 19th century. A hand search of the Index of Dental Literature published between 1839 and 1965 was conducted to locate publications on caries diagnosis, etiology, prevention, and management.
The history of dental caries diagnosis and management throughout the second millennium can be divided into two distinct periods. The first, which lasted more than 900 years and may still be going on today, is the "observational" era. The second, which has developed and revolutionized our understanding of the causes and treatments of all diseases, is the "scientific era." During the observational era, healers explained what they saw in their patients using reason, logic, and their current knowledge. They provided treatment without evaluating the outcome through the scientific method.
Many of the issues to be discussed by the presenters at this conference have been observed since the 19th century. For example, dentists reported on the presence of enamel and dentinal caries (early and advanced lesions) as early as the 1880s (Darby, 1884). Hidden caries (defined as "caries in the dentin without an opening through the enamel leading to it") was a phenomenon that was noticed in 1868 (Knapp, 1868). Early childhood caries, or "labial decay of childhood," was described in 1884 (Darby, 1884). "Secondary decay" was discussed as a problem in 1880 (Palmer, 1880). Interestingly, the problem of variation among dentists in caries diagnosis and restorative treatment decisions was reported on in 1869 (Anonymous, 1869). The cause of this ongoing problem was claimed to be the "failure in diagnosis of dental decay, even when one intends to be very thorough." The cause of variation was attributed to "the large size of the excavator used for examination," and the solution proposed was to use "the very smallest...hatchet ...with exceedingly thin blade" (Anonymous, 1869). Later on, Black advocated using a "small, very sharp exploring tine which will penetrate the decay area" (Black, 1910). Since then, the practice of using sharp explorers to find carious lesions has become a standard method without much scientific scrutiny.
During the observational era there were several competing theories on why dental caries develops. However, the one theory that was based on limited "observational and experimental data" was the chemico-parasitic theory (Miller, 1883). Dietary or "constitutional" or nutritional factors also were associated with dental caries (Wallace, 1913; Richardson, 1914).
During the late 19th century, American dentists began reporting on the epidemic of dental caries. The rise in dental caries was most noticeable among affluent, urban, white Americans. This observation led to several theories. Dental caries was considered a curse of "civilization" (Wallace, 1913).
Epidemiologic surveys were first initiated in the United States in the 1930s and 1940s. Oral health emerged as a focus for initiatives sponsored by government agencies during and after World War II as a result of the relatively large number of potential recruits who did not meet the liberal dental requirements for enlisting in military service. At the same time, the link between fluoride, fluorosis, and dental caries was confirmed by a number of cross-sectional and incidence studies (Ast, 1944; Dean, Arnold, Elvove, 1942). This link was the first major breakthrough in caries prevention.
In 1945, the first field trial to test the effectiveness of water fluoridation commenced in the United States (Arnold, Dean, Jay, 1956). Additional water fluoridation studies then led to widespread use of fluoride in caries prevention. Water fluoridation was recently cited by the Centers for Disease Control and Prevention as one of the 10 most important public health achievements of the 20th century.
The scientific era in dentistry started in the early years of the 20th century with attempts to test hypotheses and to collect data to support or refute them. Basic research led to significant advances in understanding of the histopathology of caries in enamel and dentin, microbial risk factors, the physiology and pathology of saliva, and understanding of fluoride mechanisms. Research activities led to the development of new preventive interventions and restorative materials that have had a significant impact on the restoration of decayed teeth and the retention of teeth for life. A second major development in caries prevention was scientific validation of the efficacy and effectiveness of pit-and-fissure sealants.
The etiological model proposed by Miller was expanded to include other risk factors or indicators that are associated with dental caries initiation and progression, and dental caries is now considered to have a multifactorial etiology (Clarkson, 1999). Dental caries is also recognized as a biosocial disease whose burden has shifted from affluent members of society to those who are economically disadvantaged.
During the scientific era the prevalence and severity of dental caries in the United States have declined, especially in children. There has been phenomenal growth in the biological understanding of dental caries. However, the knowledge base for diagnosis, risk assessment, translation of prevention into practice, and decision-making on placement and replacement of restorations has not progressed significantly during the last 5 decades. There has been limited investment in clinical research and in the translation of research and biological knowledge into practice. Moreover, dentists still rely on observation and uncontrolled experimentation with a few patients to make general recommendations for dental practice (Christensen, 2000).
Most of the advances in caries research in the second millennium have relied on observation and inductive reasoning. To resolve the current dilemma in caries diagnosis and management, however, the use of a scientific research model is necessary to define the problems we face and design appropriate research projects to find answers. There is an urgent need to develop new tools that can accurately diagnose the earliest signs of tooth demineralization, the natural history of early carious lesions, the determinants of progression and regression, when to restore a carious tooth, and how to classify with a high degree of sensitivity and specificity the risk status of patients. Research on these issues will not be possible without a major funding initiative to support training of a new cadre of basic and applied researchers in cariology and to develop and implement programs to address the real-life problems in diagnosis, risk assessment, and management. If the current weak trend of caries research in the United States continues, history will be harsh on all of us for our failure to use our knowledge and resources to reduce, if not eliminate, the burden of one of the world�s most prevalent diseases.
References
Anonymous. Diagnosis of dental caries. Missouri Dent J 1869;1:399�403.
Arnold FA, Jr., Dean HT, Jay P, Knutson JW. Effect of fluoridated public water on dental caries prevalence. 10th year of the Grand Rapids-Muskegon study. Pub Health Rep 1956;71:652�8.
Ast, D. Summary of papers presented at councilor dental meeting. J Wisconsin State Dent Soc 1944;20:175�7.
Black, GV. The contact point and its function, considered with reference to dental caries and its treatment. Dent Headlight 1910:31:135�43.
Christensen GJ. Initial carious lesions: when should they be restored? J Am Dent Assoc 2000;131:1760�2.
Clarkson BH. Introduction to cariology. Dent Clin North Am 1999;43:569�78.
Darby ET. The etiology of caries at the gum-margins and the labial and buccal surfaces of the teeth. Dent Cosmos 1884;26:218�32.
Dean HT, Arnold FA, Jr., Elvove E. Domestic water and dental caries. V. Additional studies of the relation of fluoride domestic waters to dental caries experience in 4,425 white children, aged 12 to 14 years, of 13 cities in 4 states. Pub Health Rep 1942;1155�79.
Hodge J. Some theoretical and practical considerations of enamel. Dent Record 1907;27:220�6.
Knapp JS. Hidden dental caries. Transact Am Dent Assoc 1868;n.v.:108�12.
Miller WD. Dental caries. Am J Dent Sci 1883;17:77�130.
Palmer SB. "Secondary" decay. Dent Cosmos 1880;22:15�21.
Richardson D. Diet and teeth. J Am Dent Assoc 1914;15:98�102.
Wallace, S. Why our civilization has given us poor teeth? J Am Dent Assoc 1913;15: 327�30.