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Miller classification of gingival recession classes I II III IV

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Miller classification gingival recession 2018 Cairo classification periodontics

Miller's Classification of Gingival Recession

"Miller's classification" (P.D. Miller, 1985) is the classic periodontics system used to categorize marginal tissue recession and predict the amount of root coverage achievable with surgical treatment. It divides recession into four classes based on the extent of tissue loss relative to the mucogingival junction (MGJ) and the presence/absence of interdental (interproximal) bone or soft tissue loss.

Class I

  • Recession does not extend to the mucogingival junction
  • No loss of interdental bone or soft tissue
  • Prognosis: 100% root coverage is predictable

Class II

  • Recession extends to or beyond the mucogingival junction
  • No loss of interdental bone or soft tissue
  • Prognosis: 100% root coverage is predictable

Class III

  • Recession extends to or beyond the mucogingival junction
  • Interdental bone/soft tissue loss is present, OR there is malpositioning of teeth, so the loss is apical to the CEJ but coronal to the extent of the marginal tissue recession
  • Prognosis: Only partial root coverage can be expected

Class IV

  • Recession extends to or beyond the mucogingival junction
  • Interdental bone loss and/or malpositioning of teeth is severe enough that the interdental soft tissue/bone loss is at the same level as the apical extent of the marginal recession
  • Prognosis: No root coverage is anticipated

Important update: this system has been superseded

Miller's classification has recognized limitations - it relies on the mucogingival junction as a landmark (often hard to identify clinically) and uses interdental bone/soft tissue loss as a subjective criterion, which reduces inter-examiner reliability. Because of this, the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases adopted the Cairo Classification (2011), based on measurable interproximal clinical attachment loss (CAL):
  • RT1 (Recession Type 1): Gingival recession with no interproximal attachment loss; CEJ not detectable or detectable but no interproximal CAL. Equivalent to Miller Class I/II.
  • RT2 (Recession Type 2): Gingival recession associated with interproximal attachment loss, where the amount of interproximal attachment loss is ≤ the buccal attachment loss.
  • RT3 (Recession Type 3): Gingival recession with interproximal attachment loss greater than the buccal attachment loss.
Studies comparing the two systems (e.g., the PMC review on reliability) found the Cairo classification is more reproducible and reliable between examiners than Miller's, largely because it avoids the ambiguous MGJ landmark, which is why current practice favors Cairo/RT staging while Miller's is still taught as the historical foundation.
Recent evidence check: a 2023 systematic review on gingival recession prevalence (PMID: 35735236) and a 2025 meta-analysis on risk factors (PMID: 39988303) don't contradict this staging framework, they focus on epidemiology rather than classification validity, so no conflict with the above.
If you want, I can also cover the treatment/root-coverage implications tied to each Miller class or walk through the Cairo/RT measurement technique in more detail.
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