Periodontology
What this domain tests
Items test the 2018 classification (stage and grade), periodontal diagnosis and charting, nonsurgical and adjunctive therapy, regeneration, and peri-implant disease.
Classification and diagnosis
- Staging uses clinical attachment loss, radiographic bone loss, probing depths, furcation and tooth loss: stage I up to 2 mm CAL, stage II 3-4 mm, stage III 5 mm or more, stage IV advanced with masticatory dysfunction.
- Grading estimates progression: grade A slow, B moderate, C rapid. Direct evidence uses bone loss over 5 years; indirect uses the ratio of percentage bone loss to age (under 0.25 = A, 0.25-1.0 = B, above 1.0 = C), modified by smoking and HbA1c above 7.0%.
- Charting includes probing depth, recession, CAL, bleeding on probing, plaque scores, furcation involvement (Glickman I-IV) and mobility.
Treatment
- Cause-related therapy: oral hygiene instruction, biofilm disruption, supra- and subgingival instrumentation, risk-factor control; re-evaluate at 6-8 weeks before deciding on surgery.
- Supportive periodontal care at individually set intervals, often 3 months for grade C.
- Adjunctive systemic amoxicillin plus metronidazole is reserved for grade C or necrotising disease; subantimicrobial-dose doxycycline is used for host modulation.
- Regeneration in intrabony defects uses guided tissue regeneration, bone grafts or enamel matrix derivative; these do not help suprabony defects or furcations of hopeless prognosis.
- Peri-implant mucositis shows bleeding with no bone loss; peri-implantitis adds progressive bone loss, and mobility appears late.
Worked example
A 50-year-old non-smoker, non-diabetic, has interproximal CAL of 5 mm on several molars, radiographic bone loss of about 40%, and no tooth loss from periodontitis. Reasoning: CAL of 5 mm with no stage IV features gives stage III. Grade is calculated as 40/50 = 0.8, which falls between 0.25 and 1.0, so grade B; no smoking or HbA1c modifier applies. The patient is stage III grade B and needs cause-related therapy with re-evaluation before any regenerative surgery.
Traps
Calculating grade from absolute bone loss rather than the age ratio; re-evaluating too early; using antibiotics as monotherapy; diagnosing peri-implantitis without bone loss.