Reference values of periodontal inflamed surface area as a clinical index determined by a multicenter retrospective observational study

Abstract

Periodontal inflamed surface area (PISA) is a new clinical index of periodontal disease that represents the inflamed area in periodontal tissue. It is considered to be a useful index even for medical professionals other than dentists, to understand the degree of inflammation of periodontal disease. However, the reference values of PISA and the criteria for both the severity of periodontal disease and the effects of treatment are still unknown. We retrospectively examined the values of PISA in each phase of periodontal treatment, based on data obtained from computerized dental records prepared by applicants for accredited dentists recognized by the Japanese Society of Periodontology (JSP) as JSP Board Certified Periodontists, and proposed reference values of PISA to show the degree of inflammation associated with periodontal treatment. PISA was calculated for 113 cases from 8 institutions by the method of Nesse et al., from the probing pocket depth and bleeding on probing (BOP). The results revealed a median value of PISA of 1,271.4 mm² at the first examination, 211.8 mm² at the end of the initial preparation, 52.1 mm² at supportive periodontal therapy (SPT) transition, and 30.0 mm² at the latest SPT. Moreover, PISA was highly correlated with BOP (p<0.001), and in fact, reflected the treatment effect more sensitively than BOP. Our findings revealed that periodontal inflammation with a PISA value of approximately 1,500 mm² at the first examination decreased to less than 100 mm² (approximately 7%) at SPT. Further accumulation of data and more detailed analysis could lead to PISA being developed as a useful index for conveying the severity of periodontal disease in cooperative medical and dental practice.