Purpose: periodontal health index is a dentist-centered index in which dentists perform examination and evaluation. Therefore, it is not appropriate for evaluation subjective symptoms and satisfaction levels of patients. To compensate for this shortcoming, we made use of a subjective index of periodontal health status with which patients can evaluate their oral health status. This research evaluated the usefulness of Periodontal age index in examining subjective consciousness of periodontal health status, estimated the number of existing permanent teeth, which is the objective index for oral health, and compared the relationships between them. Materials and Methods: The number of subjects was 2,198, consisting of 1,115 (50.7%) men and 1.083 (49.7%) women. The periodontal age increased in the 18-24 and 40-44 age groups. There were no significant differences between the 40-44 and 55-59 age groups. Further, periodontal age decreased in those aged over 60-64. Results: In this study, periodontal age index increased to age 40 when teeth are lost to periodontal disease and decreased with a decline in the number of permanent teeth. Conclusion: Therefore, the periodontal age index reflects the periodontal state rather than hypofunction by tooth loss.