Table 1 Definitions of groups of periodontitis based on periodontitis and CAL

Severe

≥ 2 interproximal sites with ≥ 6 mm CAL (not on the same tooth)

AND

≥ 1 or more interproximal site(s) with ≥ 5 mm PD

Mild-moderate

Among those who did not meet the severe periodontitis case definition;

≥ 2 interproximal sites with ≥ 3 mm CAL

AND

(≥ 2 interproximal sites with ≥ 4 mm PD (not on

the same tooth)

OR 1 site with ≥ 5 mm PD)

None

Meets neither the severe nor mild-moderate periodontitis definition