The Navy Periodontal Disease Index (NPDI) was developed as part of the Navy Periodontal Screening Examination, along with the Navy Plaque Index. It is composed of a gingival and a pocket scores. The NPDI score can be used to determine the level of treatment required by the individual patient.

Teeth examined (US designation):

(1) 3

(2) 9

(3) 12

(4) 19

(5) 25

(6) 28



(1) If 3, 12, 19 or 28 is missing, then substitute the next most posterior tooth.

(2) If 9 or 25 is missing, then substitute the nearest incisor in the arch. If all of the incisors are missing from the arch. If all incisors are missing from the arch, then substitute a cuspid.


Gingival Score


Each tooth is examined for evidence of inflammatory change, which constitutes one or more of the following findings:

(1) any change from normal gingival color

(2) loss of normal density and consistency

(3) slight enlargement or blunting of the papilla or gingiva

(4) tendency to bleed upon palpation or probing


Gingival Score


Gingival tissue is normal in color and tightly adapted to the tooth. Tooth is firm and no exudate is present.


Inflammatory changes are present but do not completely encircle the tooth.


Inflammatory changes completely encircle the tooth.



Pocket Score


With a calibrated periodontal take 6 measurements of each designated tooth:

(1) mesial facial surface

(2) middle facial surface

(3) distal facial surface

(4) mesial lingual surface

(5) middle lingual surface

(6) distal lingual surface


Pocket Measurements


Probing reveals sulcular depth not over 3 mm.


Probing reveals pocket depth greater than 3 mm but not over 5 mm.


Probing reveals pocket depth greater than 5 mm.



pocket score =

= MAX(score taken at the 6 probing sites)


Generating the NPDI


tooth score =

= (gingival score) + (pocket score)


NPDI score =

= MAX(all 6 tooth scores)


NPDI total =

= SUM(all 6 tooth scores)



• minimum tooth score: 0

• maximum tooth score: 10

• minimum NPDI score: 0

• maximum NPDI score: 10

• minimum NPDI total: 0

• maximum NPDI total: 60

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