The general acceptance and use of the CPITN system worldwide has provided, in a very short time, a vast amount of data on periodontal diseases. This data has been entered into the WHO Global Oral Data Bank, from which, after analysis, much valuable information has been derived. Overall the CPITN system is seen as having more than fulfilled the initial hopes invested in it. It has provided a simple yet effective method for measuring and monitoring the magnitude, prevalence and severity of periodontal diseases throughout the world, as well as helping in our understanding of the disease process.