GINGIVA - BASICS

 

Gingiva covers alveolar bone and  tooth root ( just above CEJ)
Divided into
- Marginal gingiva
- Attached gingiva
- Interdental gingiva

MARGINAL GINGIVA:
- Unattached gingiva
- Surrounds the tooth like "collar"
- Free gingiva groove - differentiates marginal and attached gingiva (shallow linear depression present in 50% cases)
- Gingival zenith - the most apical point of marginal gingival scallop
- Width of Marginal gingiva - about 1 mm
- Marginal gingiva forms soft tissue wall of gingival sulcus

Gingival sulcus:
- Shallow space or crevice around the tooth
- Tooth on one side - marginal gingiva on  the other side
- V shaped
- Ideally - depth of sulcus - close to 0 mm
- Clinically - in normal  healthy condition  - depth of sulcus - 2-3mm (measured using periodontal probe)
- Histologically - 1.8 mm (variation between 0-6 mm )


ATTACHED GINGIVA:
- Tightly bound to the underlying periosteum of alveolar bone. 
- Firm and resilient
- Mucogingival junction (MGJ): present in the labial and buccal aspects . - demarcates attached gingiva from the movable alveolar mucosa.
- In lingual aspect- attached gingiva terminates at the junction of lingual alveolar mucosa
- But in palatal aspect - the demarcation between attached gingiva and palatal mucosa is imperceptible 

Width of  the attached gingiva: (WAG)
- Distance between MGJ and bottom of the sulcus or pocket.
- Greatest in incisor region - 
Maxilla -  3.5-4.5 mm
Mandible - 3.3 - 3.9 mm
- Least in the first premolar region
Maxilla - 1.9 mm
Mandible - 1.8 mm
Changes in WAG:
- Increases with age 
- Increases in supraerupted teeth
( because MGJ remains stationary)
Width of keratinized gingiva = Width of attached gingiva + width of marginal gingiva