Community periodontal index of treatment needs and prevalence of periodontal conditions

Background/aims: In 1977, the World Health Organization (WHO) proposed a new index, the community periodontal index of treatment needs (CPITN) to evaluate the periodontal treatment needs of populations. The aim of this study is to compare different approaches of recording and presenting the CPITN. Methods: A sample of 2110 subjects aged 35-44 years were examined between September 1994 and July 1995, throughout the province of Quebec, Canada. For each tooth (3rd molars excluded), the presence of bleeding and calculus, the level of epithelial attachment, and the depth of periodontal pockets were measured. Periodontal pocket depths were measured from the edge of the free gingiva, at 2 sites (mesiovestibular and vestibular), as well as all around the tooth. Results: Only 8.5% of adults had at least one tooth with a 6 mm or deeper periodontal pocket when probing on 2 sites, whereas if probing is done all around the tooth, this percentageis 2.5 x higher (21.4%). The partial recording of pocket depths (10 index teeth recommended by WHO, or 2 quadrants chosen at random) resulted in an underestimation of the prevalence of subjects with at least one tooth with a periodontal pocket (CPITN score 3 and 4). Among subjects with at least one tooth with a 6 mm or deeper periodontal pocket, 12% were not detected with the 10 index teeth recording, and 25% go undetected with the measure on 2 quadrants. Finally, using the % of subjects with periodontal pockets overestimates the prevalence of deep pockets compared with using sextants. Indeed, close to 30.0% of sextants have no treatment needs, whereas only 5.2% of subjects are in this category. Similarly, 7.7% of sextants have at least one tooth with a 6 mm or deeper periodontal pocket, yet there are 3 x more subjects in this category (21.4%).