0 - No need for periodontal treatment; 1 - Oral hygiene instruction (OHI); 2 - OHI, removal of plaque retentive factors, including all supra- and SC; 3 - OHI, root surface debridement (RSD); 4 - OHI, RSD. Need for more complex treatment; referral to a specialist may be indicated; * - OHI, RSD. Assess the need for more complex treatment; referral to a specialist may be indicated.