Standardization of the Epidemiologic Assessment of Periodontal Diseases: Surveys in the South Pacific

Abstract

Attempts of introducing uniform techniques for the collection of statistical data on the prevalence of periodontal diseases have been made by FDI and WHO in order to arrive at valid, reproducible, and internationally comparable results. The WHO Manual of the International Classification of Diseases. Application to Dentistry offers a five digit classification of all oral diseases for statistical purposes. In contrast to morbidity statistics, epidemiological surveys must be based on adequate samples, representative for the entire population or distinct strata thereof. FDI is actually preparing guidelines for the conduct of clinical trials in periodontal diseases, comparable to those on caries incidence, indicating the proper use of indices. For the epidemiological assessment of periodontal diseases, the WHO Basic Methods (1962, 1971) have recommended the use of simple ratios of persons affected with signs of the disease. Data collected in four extensive dental surveys in Polynesian and Melanesian populations in the South Pacific served as an example to show the variety of valid information provided by these basic methods. The main results showed an early appearance of pocket formation at ages 10 to 14, preceded in a statistically significant way by calculus formation and gingivitis. A constant pattern in the sequence of attack of the various teeth by pocket formation was shown to be specific for these island populations; males were consistently more affected than females. The character of periodontal diseases prevalent among Polynesians and Melanesians was recognized to be a "dirt pyorrhea" accompanied by progressive subgingival calculus deposition and destructive periodontitis.