Table 2 Periodontitis Grade Primary Criteria Grade Modifiers Grade A: Slow rate of progression Grade B: Moderate rate of progression Grade C: Rapid rate of progression Direct evidence of progression Longitudinal data (radiographic bone loss or CAL) Evidence of no loss over 5 years <2 mm over 5 years ≥2 mm over 5 years Indirect evidence of progression % bone loss/age < 0.25% < 0.25-1.0% > 1.0% Case phenotype Heavy biofilm deposits with low levels of destruction Destruction commensurate with biofilm deposits Destruction exceeds expectation given biofilm deposits; specific clinical patterns suggestive of periods of rapid progression or early-onset disease (e.g., molar/incisor pattern: lack of expected response to standard bacterial control therapies) Smoking Nonsmoker Smokes < 10 cigarettes/day Smokes ≥ 10 cigarettes/day Diabetes Normoglycermic or no diagnosis of diabetes Hba1c < 7.0% in patients with diabetes HbA1c ≥ 7.0% in patients with diabetes Risk factors Systematic Impact Risk Inflammatory burden High-sensitivity CRP (hsCRP) < 1mg/L 1-3mg/L > 3mg /L Biomarkers Indicators of CAL/bone loss Saliva, gingival crevicular fluid, serum ? ? ? As seen in Table 2, a patient's grade incorporates four additional biological dimensions of periodontal disease: * The history-based periodontitis progression. * The risk of further periodontitis progression. * Any anticipated treatment outcomes. * The risk that the disease or its treatment may negatively affect the general health of the patient. According to the revised ground rules for assessing a patient's grade: * The grade is primarily defined on the basis of observed or inferred rate of periodontitis progression. 64 JANUARY 2020 // dentaltown.com * The grade is heavily influenced by the presence or control of risk factors that influence further progression and treatment outcomes. * The grade may revert to a lower level after therapy, if the risk profile of the patient improves significantly and sustainably. * When unsure, the clinician should assign Grade B (moderate rate of progression) and modify accordingly when the elements of the risk profile become clearer. The case summaries on the pages that follow illustrate how to classify periodontal disease when dealing with "the gray zones." Conclusion Periodontics, like life, would be much simpler if it involved binary black-and-white choices rather than a seemingly infi nite number of shades of gray. Used properly and consistently, the updated Classification of Periodontal and Peri-Implant Diseases and Conditions can serve as a significantly enhanced complement to the periodontist's judgment in providing best possible patient care when dealing with complex periodontal cases. ■http://www.dentaltown.com