The Sulcus Bleeding Index (SBI) can be used to assess a patient for gingivitis, which can be important in the prevention of periodontal disease. This was initially called the "PM Index", but the name was changed to prevent confusion with the "PMA Index".


Number of teeth examined: 16 (the anterior 4 in each quadrant, 2 on maxilla and 2 on mandible)


Teeth in each quadrant:

(1) medial incisor

(2) lateral incisor

(3) cuspid

(4) first premolar


4 surfaces on each tooth are probed:

(1) M labial

(2) M lingual

(3) P mesial

(4) P distal


Total number of readings: 64


Each surface is examined grossly for color and swelling, then a probe is gently placed in the sulcus to see if bleeding occurs.


Sulcus Probing



no bleeding


apparently healthy with no change in color and no swelling

bleeding on probing


change in color due to inflammation; no swelling or macroscopic edema

bleeding on probing


change in color due to inflammation; slight edematous swelling

bleeding on probing


obvious swelling

bleeding on probing


spontaneous bleeding; changes in color; marked swelling with or without ulceration

bleeding on probing




• The total number of surfaces showing each of the scores (0 to 5) is used to evaluate the distribution of changes associated with gingivitis.

• minimum sum of all SBI scores: 0

• maximum sum of all SBI scores: 320


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