Classical and Modern Methods in Caries Epidemiology

In epidemiological research the focus is on the occurrence, causes, and modifying factors of diseases and thereby their prevention. During the last decades, the epidemiology of dental caries has not dealt with the prevalence of the disease, but is measuring the past and present caries experience in terms of past and present treatment need, which does not follow the practices in epidemiology. Therefore it would be important that dental research returns the rules of (medical) epidemiology. The World Health Organization [WHO] has recommended that the International Statistical Classification of Diseases and Related Health Problems [ICD] must be followed in diagnoses by both physicians and dentist. Because of this legislation all dental patients must have one primary diagnosis and when necessary, one or multiple secondary diagnoses. The primary diagnosis is not necessarily the most serious disease but it only means that the disease which needs most treatment in time or equipment during the emergency visit or normal treatment period. This practice is meant only for statistical purposes in dental care, and therefore, represents some overview of the prevalence of diseases in that community. The same system has been used by dentists in the secondary care level in hospitals or other institutes. This WHO ́s decision recombined medical and dental professions. At the same time it also revealed that some diverse practices occurred in the use of certain common terms (for example disease prevalence) or principles of making diagnoses between dentistry and medicine. WHO determines dental caries in two different ways as discussed recently (Larmas, 2010a): in ICD it is a disease (WHO, 1977, 1992), and in oral health surveys as a process (WHO, 1997), assessing also the treatment need at the same time. Early epidemiological surveys on dental caries assessed number of persons suffering from the disease, thus, following the normal medical practice (Morelli, 1924).The aim of this review is to shed light on these diagnostic or assessment practices for epidemiological purposes.