Periodontology and Implantology: Classification and Maintenance
Periodontology and Implantology
This domain tests the 2017 World Workshop classification, the microbial and host basis of periodontal destruction, nonsurgical and surgical therapy, and implant maintenance.
Core rules
- Staging describes severity and complexity of management: Stage I CAL 1–2 mm, Stage II CAL 3–4 mm, Stage III CAL ≥5 mm with probing depth ≥6 mm and up to four teeth lost, Stage IV with five or more teeth lost plus complex rehabilitation needs.
- Grading describes rate of progression using the ratio of percentage radiographic bone loss to age: below 0.25 is Grade A, 0.25–1.0 is Grade B, above 1.0 is Grade C. Modifiers - smoking ≥10 cigarettes/day and HbA1c ≥7.0% - shift the grade to C.
- Biofilm initiates disease; the host response determines destruction. Diabetes and smoking are the two dominant modifiable risk factors.
- Nonsurgical periodontal therapy is reassessed at 6–8 weeks before any surgical decision; adjuncts include subantimicrobial dose doxycycline 20 mg twice daily and local drug delivery.
- Implant health requires absence of bleeding on probing, no increase in probing depth and no bone loss beyond expected crestal remodelling. Peri-implant mucositis is reversible inflammation; peri-implantitis adds progressive bone loss.
Worked example
A 50-year-old with a worst probing depth of 7 mm, CAL 5 mm, 40% radiographic bone loss, two teeth lost to periodontitis, 15 cigarettes daily and HbA1c 8.2%. Severity gives Stage III. Bone loss divided by age = 40/50 = 0.8, which alone gives Grade B, but both modifiers (smoking ≥10/day, HbA1c ≥7.0%) push the grade to C. The diagnosis is generalised Stage III Grade C periodontitis, and the management implication is that grade C predicts rapid progression, so shorter maintenance intervals and stricter risk-factor control are indicated.
Traps
- Mixing stage and grade - stage is current severity, grade is rate of progression.
- Declaring peri-implantitis on pocket depth alone without bone loss and bleeding.
- Performing regenerative surgery before reassessing response to nonsurgical therapy.