Periodontal Disease

Normal Gingiva (PD 0)

Normal, healthy gingiva with sharp non-inflamed margins





Gingivitis (PD 1)

Inflammation only. No support loss.



Early Periodontal Disease (PD 2)

<25% support loss.

Stage two canine periodontal disease


Radiograph with probe inserted


Moderate Periodontal Disease (PD 3)

25–50% support loss.



Mandibular fourth premolar (canine)


Radiograph of the mandibular molar showing moderate periodontal disease (feline)


Advanced Periodontal Disease (PD 4)

>50% support loss.

Canine gingival recession


Supereruption (extrusion) of the left mandibular canine (feline patient)


Radiograph of feline alveolar bone expansion


Furcation Involvement and Exposure

The furcation is the area where multiple roots diverge from the tooth. Furcation involvement or exposure occurs secondary to periodontal disease.

  • F 1 (furcation involvement) is a depression in the furcation area that extends less than half way under the crown in a multirooted tooth.
  • F 2 (furcation involvement) exists when a depression in the furcation area extends greater than half way under the crown but not completely through.
  • F 3 (furcation exposure) exists when a periodontal probe extends through one side of the furcation and out the other side.
Stage 1 (F1) furcation involvement


Stage 2 (F2) furcation involvement


Stage 3 (F3) furcation exposure. In stage 3 furcation exposures, the periodontal probe advances "through and through."


Gingival Recession

Gingival recession is a pathological movement of the gingival margin away from the tooth. This causes the root surface to be exposed. Gingival recession is measured from the cementoenamel junction to the gingival margin.

Gingival recession upper fourth premolar



Gingival Hyperplasia (GH)

Gingival hyperplasia is the proliferation of the attached gingiva. Gingival hyperplasia is measured from the cementoenamel junction to the gingival margin.

Gingival hyperplasia


Mucogingival Defects

Mucogingival defects are deviations from the normal anatomic relationship between the gingival margin and the mucogingival junction (MGJ). Common mucogingival conditions are recession, absence or reduction of keratinized tissue and probing depths extending beyond the MGJ.

Mucogingival defect caused by hair licking


Palatal Pocket

Loss of attachment often occurs on the palatal surface of the maxillary canines. If untreated, these defects can progress to the nasal cavity.

12 mm periodontal palatal pocket caused by periodontal disease


Oronasal Fistula (ONF)

Oronasal fistula is a pathological opening in the oral cavity communicating with the nasal cavity. It is usually related to severe periodontal disease.

View into nasal cavity space where maxillary canine resided