For comprehensive evaluation of periodontal health,
we measured several periodontal indices (CPI, Russell’s
periodontal index and papillary bleeding index). CPI is a
widely used method to assess and summarize periodontal
health status in epidemiological studies but is sensitive
to individual error when measuring periodontal
pocket depth [27]. To overcome this limitation we used
the Russell’s periodontal index, with dental panoramic
x-ray to assess periodontal health objectively. In panoramic
X-ray, interproximal alveolar bone loss can be
detected easily, but alveolar bone loss occurring on
buccal, lingual or palatal sites cannot be detected. We
therefore combined the two methods (CPI, Russell’s
periodontal index) to assess periodontal health more
accurately, together with papillary bleeding index to
assess gingivitis. Strength of this study was the comprehensive
assessment of periodontal health using these
three complementary indices.