Comparison of the Periodontal Index (PI) and Community Periodontal Index of Treatment Needs (CPITN)

692 dental adults in the age ranges, 15-19, 20-29, and 35-44 yr, were assessed for their periodontal conditions and treatment needs using the Periodontal Index (PI) and Community Periodontal Index of Treatment Needs (CPITN). The relative advantages and disadvantages of the two indices were evaluated as epidemiological screening procedures. The CPITN (which calls for examination of only 10 selected teeth) identified higher proportions of adults and teeth with a healthy periodontal condition and also those with periodontitis than the PI (which requires examination of all teeth). The proportion of adults and teeth with gingivitis as the worst condition was greater than when assessed by the PI. Evaluation of individual adult scores by PI and CPITN suggested that the CPITN, despite being a partial recording index only, is more sensitive in identifying existing periodontal conditions and treatment needs than the PI. This is explained by the clinical criteria and periodontal probe utilized in the CPITN. Although the original purposes of the PI and CPITN differ, it is proposed that as a epidemiological screening procedure for assessing periodontal treatment needs the CPITN is to be preferred to the PI.