This article consists of a critical analysis of the CPITN, an index based on binary logic and the partial recording of data. The authors discuss the possible loss of information connected with the fact that the data collection covers 6 scores per individual instead of more comprehensive scoring for which there are methods involving several surfaces per tooth. This approach is discussed on the basis of research carried out by the authors and a review of the literature. Moreover, one aspect of the CPITN which often gives rise to controversy is whether recession is pathological or not, and therefore to what extent it should be recorded. This aspect is discussed and analysed. Finally, quantification of the time needed to provide periodontal care is also relevant when using this index, which is the reference index for the WHO Global Oral Data Bank.