3.1 Periodontology
Key Takeaways
- The 2017 World Workshop (AAP/EFP) replaced the chronic/aggressive split with a single 'Periodontitis' category staged I-IV by severity/complexity and graded A-C by progression rate and risk modifiers (smoking, HbA1c)
- BPE is a screening tool only: codes 0-4 and * (furcation); Code 3 triggers 6-point charting of that sextant post-therapy, Code 4 triggers full-mouth 6-point charting pre- and post-therapy
- Grade C is indicated by >=2 mm CAL over 5 years, >1.0% bone loss/age ratio, >=10 cigarettes/day, or HbA1c >=7.0% in patients with diabetes
- Miller Class I and II recession (no interdental bone loss) predict 100% root coverage; Class IV (severe interdental loss) predicts no root coverage
- Sub-antimicrobial-dose doxycycline (20 mg bid) is not used in UK periodontal therapy; systemic antimicrobials are an adjunct to SRP in specific scenarios only, not a substitute
2017 World Workshop Classification
The 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions, co-sponsored by the American Academy of Periodontology (AAP) and the European Federation of Periodontology (EFP), replaced the 1999 chronic/aggressive split with a single Periodontitis category described by a multidimensional staging and grading framework. The old terms 'chronic' and 'aggressive' are no longer used as primary diagnoses.
Staging (Stages I-IV)
Staging reflects severity and complexity of management. The initial stage is set by interdental clinical attachment loss (CAL) at the site of greatest loss; radiographic bone loss (RBL) is used when CAL is unavailable. Tooth loss due to periodontitis and complexity factors can shift the stage upward.
| Feature | Stage I | Stage II | Stage III | Stage IV |
|---|---|---|---|---|
| Interdental CAL | 1-2 mm | 3-4 mm | >=5 mm | >=5 mm |
| RBL | Coronal third (<15%) | Coronal third (15-33%) | Extending to middle third of root and beyond | Extending to middle third and beyond |
| Tooth loss due to periodontitis | None | None | <=4 teeth | >=5 teeth |
| Complexity | Max PD <=4 mm; horizontal bone loss | Max PD <=5 mm; horizontal bone loss | PD >=6 mm; vertical defects >=3 mm; furcation II/III; moderate ridge defects | Complex rehabilitation; secondary occlusal trauma (mobility >=2); <20 remaining teeth |
An extent descriptor is appended to each stage: localized (<30% of teeth), generalized, or molar-incisor pattern.
Grading (Grades A-C)
Grading indicates the rate of progression, responsiveness to standard therapy, and systemic impact. Clinicians should initially assume Grade B and seek evidence to shift to A or C.
| Evidence | Grade A (slow) | Grade B (moderate) | Grade C (rapid) |
|---|---|---|---|
| Direct (progression over 5 years) | No loss | <2 mm | >=2 mm |
| Indirect (% bone loss / age) | <0.25 | 0.25-1.0 | >1.0 |
| Smoking (risk modifier) | Non-smoker | <10 cigarettes/day | >=10 cigarettes/day |
| Diabetes (risk modifier) | Normoglycemic | HbA1c <7.0% | HbA1c >=7.0% |
Direct evidence of progression should be used whenever available, as it is more reliable than the indirect ratio.
Basic Periodontal Examination (BPE)
The BPE is the UK screening tool recommended by the British Society of Periodontology (BSP). It is a screening tool only, not a diagnostic tool, and cannot be used to monitor response to therapy. The mouth is divided into six sextants; each sextant is scored by running a WHO CPI probe (0.5 mm ball tip, black band 3.5-5.5 mm) around all teeth in the sextant, recording the highest code found.
| Code | Finding | Management |
|---|---|---|
| 0 | Pockets <3.5 mm, no calculus/overhangs, no bleeding | No periodontal treatment |
| 1 | Pockets <3.5 mm, no calculus/overhangs, bleeding on probing | Oral hygiene instruction (OHI) |
| 2 | Pockets <3.5 mm, supra/subgingival calculus or overhangs | OHI + removal of plaque retentive factors |
| 3 | Probing depth 3.5-5.5 mm (black band partially visible) | OHI + root surface debridement (RSD) if required; 6-point charting of that sextant at re-evaluation; radiographs for that sextant |
| 4 | Probing depth >5.5 mm (black band disappears) | OHI + RSD; full-mouth 6-point pocket chart pre- and post-therapy; assess complex treatment and referral |
| * | Furcation involvement | Treat per the accompanying BPE code; assess complexity and referral |
BPE Recall and Re-evaluation
- Codes 0, 1, 2: Record BPE at every routine examination.
- Code 3: Record a 6-point pocket chart of the affected sextant at post-treatment re-evaluation.
- Code 4: Record a full-mouth 6-point pocket chart pre- and post-therapy.
- Maintenance phase: Full probing depths throughout the dentition at least annually.
- BPE should not be used around implants; use 4- or 6-point pocket charting instead.
- BPE is not used for children and adolescents under 18 (use the modified BPE/Basic Screening Examination).
Risk Factors and Initial Therapy
Modifiable Risk Factors
- Smoking: Dose-dependent effect on prevalence and severity; impairs neutrophil function, reduces cytokine production, vasoconstricts gingiva (masking bleeding). Grade C risk modifier at >=10 cigarettes/day.
- Diabetes mellitus: Bidirectional relationship; hyperglycaemia increases AGE accumulation, neutrophil dysfunction, and collagen breakdown. HbA1c >=7.0% denotes Grade C. Well-controlled diabetes (HbA1c <7.0%) is Grade B.
- Plaque retentive factors: Calculus, overhanging restorations, open contacts, crowding, partial dentures.
Initial Cause-Related Therapy
Stage I and II periodontitis is managed in primary care with initial therapy:
- Oral hygiene instruction (OHI) tailored to the patient
- Removal of plaque retentive factors (calculus, overhangs)
- Root surface debridement (RSD), also called scaling and root planing (SRP), under local analgesia
- Re-evaluation at 6-8 weeks: record 6-point pocket chart, assess response
- Supportive periodontal therapy (SPT): recall intervals based on risk and disease severity, typically 3-6 months for periodontitis patients
Referral Criteria
Refer to a specialist (restorative/periodontal) when there is:
- Stage III or IV periodontitis
- Grade C progression
- Furcation involvement (especially Class II/III)
- Inadequate response to initial therapy (persistent pockets >=6 mm after RSD)
- Periodontitis as a manifestation of systemic disease
- Molar-incisor pattern with rapid attachment loss
Systemic Antimicrobials in Periodontics
Systemic antibiotics are not routine in periodontal therapy. They are an adjunct to mechanical debridement in specific situations only (e.g., aggressive/Grade C disease, necrotising periodontal diseases, specific microbiological indications). Amoxicillin 250 mg + metronidazole 250 mg, both tds for 7 days, is a commonly cited regimen for severe periodontitis, prescribed after completion of RSD. Local antimicrobial delivery (e.g., minocycline microspheres, doxycycline gel) has limited evidence and is not a substitute for mechanical debridement.
Periodontal Abscess and Perio-Endo Lesions
Periodontal Abscess
A periodontal abscess is a localised purulent infection within the periodontal tissues, arising from an exacerbation of an existing periodontal pocket. Clinical features: localised swelling, pain, tooth tenderness to percussion, increased mobility, and often drainage from the pocket. Management: drainage (through the pocket or by incision), debridement of the pocket, irrigation, and supportive analgesia. Systemic antibiotics are indicated only if there is spreading infection, systemic symptoms (fever, malaise), or immunocompromise. After acute management, definitive periodontal therapy is required.
Perio-Endo Lesions
A perio-endo lesion is a communication between periodontal and pulpal pathology at the apex or through a lateral canal. Classification (Simon et al.):
- Class I (primary endo): Pulpal necrosis drains through the periodontal ligament, creating a 'pocket' that is narrow and localised. Treat endodontically; periodontal prognosis is good.
- Class II (primary perio): Periodontal disease reaches the apex, causing secondary pulpal involvement. Periodontal prognosis is the limiting factor.
- Class III (true combined): Independent periodontal and endodontic lesions coexist on the same tooth. Both must be treated; overall prognosis depends on the periodontal component.
- Class IV (secondary endo): Periodontal disease causes retrograde pulpal involvement.
A solitary deep narrow pocket on an otherwise healthy dentition, or a 'wide' pocket on a single-rooted tooth with a non-vital pulp, suggests a primary endo component. Vitality testing is essential before assuming the lesion is purely periodontal.
Miller Classification of Recession and Occlusal Trauma
Miller Classification (1985)
| Class | Recession to MGJ? | Interdental bone/soft tissue loss | Expected root coverage |
|---|---|---|---|
| I | No | None | 100% (complete) |
| II | Yes (to or beyond) | None | 100% (complete) |
| III | Yes | Some loss and/or tooth malposition | Partial |
| IV | Yes | Severe loss and/or severe malposition | None (poor) |
MGJ = mucogingival junction. The classification cannot be applied to palatal surfaces of maxillary teeth (no MGJ). The Cairo classification (RT1/RT2/RT3, 2011) is a modern alternative based on interproximal CAL with better inter-examiner reproducibility.
Occlusal Trauma
- Primary occlusal trauma: Excessive force on a tooth with normal periodontal support (e.g., a high restoration, bruxism). Changes are reversible on removal of the force; no attachment loss occurs.
- Secondary occlusal trauma: Excessive or normal force on a tooth with reduced periodontal support. May accelerate attachment loss and mobility. Management requires both periodontal therapy and occlusal adjustment/splinting.
Mobility is graded: grade 1 = <=1 mm, grade 2 = 1-2 mm, grade 3 = >2 mm and/or vertical (depressible). Stage IV periodontitis explicitly includes secondary occlusal trauma (mobility >=2) as a complexity factor.
A 45-year-old patient has interdental CAL of 3 mm at the worst site, radiographic bone loss in the coronal third (20%), no teeth lost to periodontitis, and maximum probing depth 5 mm with horizontal bone loss. No smoking, no diabetes. What is the correct 2017 classification?
A patient's BPE records codes 4, 3, 4, 3, 4, 2 across the six sextants. What is the minimum periodontal charting required before definitive therapy?
A 38-year-old smoker (15 cigarettes/day) with type 2 diabetes (HbA1c 8.2%) has 2 mm interdental CAL over 4 years and radiographic bone loss extending into the middle third of the root with a furcation Class II on the upper molars. Which grade and stage apply?
A patient presents with a 3 mm gingival recession on the lower left canine that does not reach the mucogingival junction, with no interdental bone loss on radiograph. What Miller class is this, and what root coverage can be anticipated?
A single-rooted lower premolar has a narrow, deep pocket on the mesial aspect reaching the apex, with a normal probing depth elsewhere around the tooth. The pulp tests non-vital. What is the most likely diagnosis and initial management?