Periodontology
Core concepts
Know gingival and periodontal anatomy, the 2017 classification of periodontal and peri-implant diseases (staging and grading), and the pathogenesis of plaque-induced inflammation. Understand clinical parameters: probing depth, clinical attachment level, bleeding on probing, recession, and mobility. Learn nonsurgical therapy (scaling and root planing, oral hygiene instruction), risk factors (smoking, diabetes, genetics), and surgical options (flap surgery, grafts, regeneration). Peri-implant mucositis vs peri-implantitis distinction is high-yield.
Traps
Probing depth alone does not define attachment loss; CAL is the key measure. Staging uses severity and complexity (CAL, bone loss, tooth loss); grading uses progression risk (smoking, diabetes, rate of bone loss). Aggressive periodontitis is now under a staging/grading framework rather than the old terminology. Questions often test that bleeding on probing indicates inflammation but is not specific for progressive disease. Peri-implantitis requires bone loss plus inflammation; mucositis has inflammation without bone loss.
Worked example
Rule of thumb: "Stage = how bad now; Grade = how fast and how risky." A 45-year-old smoker with 6 mm CAL, bone loss to mid-root, and no tooth loss = Stage III, Grade C (smoking and rapid progression). If the stem asks the first treatment for chronic periodontitis, the answer is nonsurgical periodontal therapy with re-evaluation, not immediate surgery.