Staging and grading a 47-year-old smoker with uncontrolled diabetes
A 47-year-old woman is referred for management of generalised periodontitis. She has type 2 diabetes (HbA1c 8.4%) managed with metformin 1 g twice daily, and smokes 12 cigarettes daily. She takes no other medication and reports no other systemic disease. Full-mouth charting shows generalised probing depths of 4–5 mm, bleeding on probing at 62% of sites, and a plaque score of 32%. The worst site is the mesial aspect of the mandibular left first molar: probing depth 8 mm, clinical attachment loss 7 mm, bleeding with suppuration, a 3 mm vertical defect on the radiograph, and class II furcation involvement. Radiographs show approximately 55% bone loss at that tooth and 20–35% elsewhere. Two teeth (maxillary right first molar and mandibular left second molar) were previously lost to caries. She reports no mobility, no pain, and no history of tooth loss attributed to periodontal disease. She has never received periodontal treatment and has had no radiographs for six years.
1. Assign a stage and a grade using the 2017 AAP/EFP classification. Justify every element from the data given, and state what additional information you need before the stage is finalised.
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Stage III.
- Interdental CAL at the worst site is 7 mm (≥5 mm), which places her at Stage III or above.
- Radiographic bone loss of 55% extends into the middle third of the root, consistent with Stage III.
- Tooth loss attributable to periodontitis is zero (both missing teeth were lost to caries), so the Stage IV criterion of ≥5 teeth lost is not met.
- Complexity factors confirm Stage III: probing depth ≥6 mm, vertical defect ≥3 mm, and class II furcation involvement.
Grade C.
- There is no direct evidence of progression (no previous radiographs or chartings), so indirect evidence must be used.
- Worst-site percentage bone loss ÷ age = 55 ÷ 47 ≈ 1.17, which exceeds 1.0 and therefore indicates Grade C.
- Modifiers are consistent: smoking ≥10 cigarettes/day shifts the grade to C, and HbA1c ≥7.0% also shifts to C. Neither modifier can lower a grade, so even a borderline ratio would still end at C here.
Data still needed: verified reason for each missing tooth; probing depth and CAL at six sites per tooth for the full dentition; mobility and fremitus; full-mouth radiographic bone levels including the furcation assessment; presence of traumatic occlusal forces; and whether any defect reaches the apical third, which would change the staging logic. Stage is assigned from the worst site, not the mean, so incomplete charting can misclassify the patient.
2. Three months after full-mouth subgingival instrumentation the mesial aspect of the mandibular left first molar still shows 6 mm probing depth with bleeding and suppuration. All other sites are ≤4 mm with bleeding at 15% of sites. HbA1c has fallen to 8.1%. What do you do next, and why?
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This is a single residual site, not a failure of phase I therapy, so the response must be site-specific and staged:
- Re-check self-care and access. Plaque score and interdental cleaning technique determine whether re-instrumentation can work; check for calculus, overhanging restoration, and occlusal trauma (fremitus, mobility).
- Re-instrument the site under local anaesthesia, with ultrasonic and hand instruments, and verify with a probe that the furcation and the base of the defect are reached. Adjuncts (local delivery, subgingival irrigation) may be used but do not replace mechanical debridement.
- Do not prescribe systemic antibiotics for one residual pocket. Systemic antibiotics are an adjunct to full-mouth debridement in specific patients, and their benefit does not justify the resistance and adverse-effect costs here.
- Re-evaluate in 6–8 weeks. Persistence of 6 mm depth, bleeding, and suppuration at a class II furcation site indicates a poor local prognosis; options are surgical access, furcation management, or extraction, weighed against the strategic value of the tooth and the patient's plaque control.
- Address risk. Suppuration plus poor glycaemic control (8.1%) and smoking predictably reduce healing; reinforce physician liaison for diabetes and referral for smoking cessation.
The key judgement is that suppuration with a deep pocket at a furcation is a warning sign, but retreatment and risk-factor control must be given a defined period before declaring the site refractory.
3. What additional findings during reassessment would move this patient from Stage III to Stage IV, and how would that alter your overall plan rather than just the local treatment?
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Stage IV requires a Stage III level of attachment loss plus at least one complexity factor reflecting the need for rehabilitation:
- ≥5 teeth lost due to periodontitis (rather than caries) - the history of the two missing teeth would need to be re-examined, since patients often misattribute loss.
- Masticatory dysfunction, bite collapse, drifting, flaring, or <20 remaining teeth (10 opposing pairs).
- Secondary occlusal trauma with mobility ≥2 mm or fremitus.
- Severe ridge defect that would prevent implant placement without augmentation.
If the stage becomes IV, management changes at the patient level, not merely the site level: prognosis becomes more guarded and the plan must include strategic extraction decisions, a multidisciplinary phase (prosthodontics, orthodontics, sometimes implant planning), a discussion about whether to retain or replace teeth, and explicit expectation-setting about how many teeth can realistically be maintained. Stage IV also changes the maintenance contract - shorter intervals, an agreed exit strategy for teeth with hopeless prognosis, and documentation of the rehabilitation plan. The important examinable point is that stage reflects severity and complexity of rehabilitation, while the grade reflects progression risk; a change in grade alone would not trigger this rehabilitation pathway, but would intensify risk-factor management and review frequency.