Based on;
1. Lang N P, Tonetti M S. Periodontal risk assessment (PRA) for patients in supportive periodontal therapy (SPT). Oral Health Prev Dent. 2003; 1: 7-16.
2. American Academy of Periodontology (AAP) and the European Federation of Periodontology (EFP). The Classification of Periodontal and Peri-Implant Diseases and Conditions. 2017.