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Epidemiology, general considerationsEpidemiology is the study of distribution of diseases, their prevalence and determinants in man (1).Consequently, the aim of endodontic epidemiology is primarily to gain knowledge of distribution and prevalence of apical periodontitis and its determinants including treatment outcome in different populations evaluated by presence/absence of apical periodontitis. Descriptive/analytical epidemiologyEpidemiology may be divided in a descriptive and an analytical part.The former is applied in order to gain knowledge about distribution and prevalence of a specific disease, in this case apical periodontitis, while the latter focuses on factors that may be associated with the disease.Cross-sectional studies are used primarily for descriptive purposes, while cohort and case/control studies are suited for disclosing disease determinants and etiologic factors (Fig. 1).
Eriksen et al. (Mon,) studied this question.