The 2018 AAP/EFP Classification of Periodontal & Peri-implant Diseases

Course Number: 610

Requirements of a Periodontitis Case

In order for an individual to be diagnosed as a periodontitis case, there are three essential requirements:12

  1. Detectable clinical attachment loss (CAL) at two (2) non-adjacent teeth.

  2. Identification of the form of periodontitis i.e., necrotizing periodontitis, periodontitis as a manifestation of systemic disease, or periodontitis.

  3. Description of the case characteristics and aggressiveness of the disease by Stage and Grade.

Table 9. Periodontitis Stages.

Periodontal StageStage IStage IIStage IIIStage IV
SeverityInterdental CAL at site of greatest loss1-2mm3-4mm≥5mm≥5mm
Radiographic Bone LossCoronal third (<15%)Coronal third (15%-33%)Extending to mid-third of root and beyondExtending to mid-third of root and beyond
Tooth LossNo tooth loss due to PeriodontitisNo tooth loss due to PeriodontitisTooth loss due to Periodontitis of ≤4 teethTooth loss due to Periodontitis of ≥5 teeth
ComplexityLocalMaximum Probing Depth ≤4mm
Mostly horizontal bone loss
Maximum Probing Depth ≤5mm
Mostly horizontal bone loss
In addition to Stage II complexity:
Probing depth ≥6mm
Vertical bone loss ≥3mm
Furcation involvement
Class II or III
Moderate ridge defect
In addition to Stage III complexity:
Need for complex rehabilitation due to:
Masticatory dysfunction
Secondary occlusal trauma
(tooth mobility degree ≥2)
Severe ridge defect
Bite collapse, drifting, flaring
Less than 20 remaining teeth
(10 opposing pairs)
Extent and distributionAdd to Stage as DescriptorFor each stage, describe extent as localized (<30% teeth involved), generalized, or molar/incisor pattern

Adapted from Tonetti et al.12

Table 10. Periodontitis Grade.

Periodontitis GradeGrade A
Slow rate of progression
Grade B
Moderate rate of progression
Grade C
Rapid rate of progression
Primary CriteriaDirect Evidence of ProgressionLongitudinal data
(Radiographic bone loss or CAL)
Evidence of no loss over 5 years<2mm over 5 years≥2mm over 5 years
Indirect Evidence of Progression% Bone Loss<0.250.25 - 1.0>1.0
Case PhenotypeHeavy biofilm deposits with low levels of destructionDestruction commensurate with biofilm depositsDestruction exceeds expectation given biofilm deposits; specific clinical patterns suggestive of periods of rapid progression and/or early-onset disease (e.g., molar/incisor pattern; lack of expected response to standard bacterial control therapies)
Grade ModifiersRisk FactorsSmokingNon-smokerSmoker <10 cigarettes/daySmoker ≥10 cigarettes/day
DiabetesNormoglycemic/no diagnosis of diabetesHbA1c <7.0%HbA1c ≥7.0% in patients with diabetes

Adapted from Tonetti et al.12