A proper diagnosis for a disease can be only given when the physician is able to know the group where it belongs to. Three major determinants of periodontal health include microbiological determinants host determinants, and environmental determinant. Periodontal disease can be grouped as periodontitis, necrotizing periodontitis, and periodontitis as a manifestation of systemic conditions

4. Plaque-induced
gingival
diseases
Non–plaque
induced gingival
lesions

6. I. Gingivitis associated with dental plaque only
A. Without local
contributing factors
B. With local
contributing factors

7. Pyogenic
granuloma

17. VI. Traumatic lesions
(factitious, iatrogenic,
or accidental)
A. Chemical
injury
B. Physical
injury
C. Thermal
injury

19. Localized Generalized

22. Localized
form: <30%
of teeth
involved
Generalized
form: >30%
of teeth
involved
Mild: 1 to 2
mm clinical
attachment
loss (CAL)
Moderate: 3
to 4 mm
CAL
Severe: ≥5
mm CAL

24. Localized Generalized

28. Necrotizing
ulcerative gingivitis
(NUG)
Necrotizing
ulcerative
periodontitis (NUP)

30. Gingival
abscess
Periodontal
abscess
Pericoronal
abscess

31. Endodontic–
periodontal
lesion
Periodontal–
endodontic
lesion
Combined
lesion

32. Localized tooth-
related factors
that predispose
to plaque
induced
Gingival
diseases or
periodontitis
Mucogingival
deformities and
conditions
around teeth
Mucogingival
deformities and
conditions on
edentulous
ridges
Occlusal
trauma