1. Oral Mucosa
Dr Jamal Naim
PhD in Orthodontics
Gingiva

2. Junctions in the Oral Mucosa
Within the oral mucosa there are three junctions:
Mucocutaneous junction: – between skin and oral mucosa
Mucogingival junction: The linear junction between the lining mucosa of the vestibule and the masticatory mucosa of the gingiva.
Dentogingival junction – between tooth and free gingiva

3. Mucogingival junction
Lining mucosa of alveolar mucosa and attached gingiva meet each other abruptly at the mucogingival junction.
Clinically it is identified by a slight indentation called mucogingival groove and by the change from the bright pink of the alveolar mucosa to the paler pink of the attached gingiva.
Mucogingival junction is not present on the palatal aspect of the upper jaw.

4. Mucogingival junction

5. Mucogingival junction
Lingual aspect of the mandible showing the tightly adhering gingiva (G) and the adjacent non-keratinized alveolar mucosa (AM) that lines part of the alveolar process and floor of the mouth (F). MGJ, mucogingival junction.

6. Mucogingival junction
This view of the hard palate shows the absence of a mucogingival junction on the palatal aspect. Instead, the masticatory mucosa of the gingiva (G) blends imperceptibly with the masticatory mucosa  of the hard palate (PM).  Note the palatal rugae (RR), the ridges behind the anterior teeth, on either side of the incisive papilla (IP).

7. Gingiva
Gingiva is that portion of the oral mucosa that covers the tooth-bearing part of the alveolar bone and the cervical neck of the tooth
Gingiva is pale pink in color; in colored races gingiva is pigmented.

8. Gingiva

9. Gingiva Morphologically gingiva is divided into: Attached gingiva
Free gingiva
Gingival sulcus
The interdental papilla.
The width of the keratinized gingiva (attached gingiva plus the free gingiva) may vary from 1.0 mm to 9.0 mm

10. Gingiva Diagrammatic view of gingiva
AB, alveolar bone; AC, alveolar crest; AM, alveolar mucosa; AP, alveolar process; CB, compact bone of alveolar bone proper;  CEJ, cemento-enamel junction; CT, connective tissue; DEJ, dentino-enamel junction;  ES, enamel space;  G, gingiva; GE, gingival epithelium;  GG, gingival groove; GM, gingival margin; GS, gingival sulcus; JE, junctional epithelium;   MGJ, mucogingival junction; MS, marrow space;   OE, oral epithelium; PDL, periodontal ligament;   RCE, radicular (root) cementum; SE, sulcular epithelium;

11. Attached gingiva
The bulk of the gingiva is firmly attached to the tooth and the alveolar bone by well-developed collagenous fiber bundles
It extends from the free gingival groove to the mucogingival junction which separates the attached gingiva from the alveolar mucosa.
Its surface shows stippling - "orange peel" appearance-.

12. Attached gingiva

13. Attached gingiva
The epithelium of the attached gingiva is keratinized or parakeratinized
The lamina propria contains numerous collagen bundles attaching the tissue to the periosteum
The collagen bundles cause the stippling, and the absence of the stippling don’t denote always inflammation.

14. Attached gingiva
The width of attached gingiva varies for each tooth. In general, the attached gingiva is wider in the maxilla, especially on the labial surfaces of the incisors, and narrowest over the buccal surfaces of the mandibular canines and first pre molars and the lingual surfaces of the mandibular incisors.
The width of the attached gingiva varies from 1.0 to 6.0 mm.

15. Attached gingiva
In about one third of all individuals, a shallow free gingival groove runs parallel to the gingival margin along a line that is located roughly at the junction between the free gingiva and the attached gingiva.

16. Attached gingiva
The free gingival groove lies approximately at the same level of the bottom of the gingival sulcus.
It demarcates the free gingiva and attached gingiva
There is no significant change between free gingiva and attached gingiva, only the stippling is not more present

18. Attached gingiva
The attached gingiva depressed between the eminencies of the sockets forming grooves called interdental grooves

19. Free gingiva
A clinical term that refers to that portion of the gingiva believed to be "free," that is, not attached to the tooth.
It surrounds the gingival sulcus and covers approximately 1.0 to 1.5 mm of the tooth surface.
It extends along the cervical level of the tooth at the labial, buccal and lingual surfaces.
It tapers to a knife edge (gingival margin).

20. Gingival sulcus
It is a shallow groove lined by non-keratinized epithelium and its bottom present at the point of separation of the attached epithelium from the tooth.
Its average depth is about 1-2mm.
The more shallow the sulcus the more favorable the condition of the gingival margin.
Lymphocytes and plasma cells are commonly seen in the C.T. at the bottom of the gingival sulcus.

21. Gingival sulcus
This is a defense reaction against bacteria and their toxins which present in the gingival sulcus.

22. Interdental papilla
The gingiva that occupies the interdental spaces coronal to the alveolar crest is the interdental gingiva.
It is composed of a pyramidal interdental papilla in the incisor region.

23. Interdental papilla
In the posterior region it is composed of an oral and a vestibular papilla (P) joined by an interdental col. 
interdental papilla in the incisor region
interdental papilla in the posterior region

24. Interdental papilla
In cases where no contact point (e.g. diastema) the interdental papilla is reduced in height.

25. Interdental papilla
Interdental papilla have a tent shape labially and buccally but wedge shape lingually, where the base corresponds to a line connecting the margin of the gingiva at the center of one tooth to the center of the next one, and the apex tapers to the contact area.

26. Epithelial Components of the Gingiva
The gingival epithelium is subdivided into 3 sections:
the oral epithelium (OE),
the sulcular epithelium (SE), and
the junctional epithelium (JE).

27. Epithelial Components of the Gingiva
The oral epithelium extends from the mucogingival junction to the gingival margin. 
It is continuous with the sulcular epithelium that lines the lateral aspect of the gingival sulcus. 
The junctional epithelium forms the dentoepithelial junction apical to the sulcus. Its coronal end forms the bottom of the gingival sulcus and is overlapped by the sulcular epithelium.

28. Epithelial Components of the Gingiva
These epithelia differ from one another in their function and, therefore, in some of their histological characteristics.
oral epithelium:
It is the stratified, squamous keratinized epithelium.
sulcular epithelium:
It is the stratified, squamous epithelium, non-keratinized or parakeratinized, that is continuous with the oral epithelium and lines the lateral surface of the sulcus.

29. Epithelial Components of the Gingiva
This epithelium shares many of the characteristics of the oral epithelium, including good resistance to mechanical forces and relative impermeability to fluid and cells.
Sulcular epithelium:
CT, connective tissue
GS, gingival sulcus
PKE, parakeratinized epithelium

30. Epithelial Components of the Gingiva
3. Junctional epithelium:
It is the stratified non-keratinizing epithelium, that surrounds the tooth like a collar with a cross-section resembling a thin wedge.
It is attached by one broad surface to the tooth and by the other to the gingival connective tissue.

31. Epithelial Components of the Gingiva
The junctional epithelium has 2 basal laminas, one that faces the tooth (internal basal lamina) and one that faces the connective tissue (external basal lamina).
The proliferative cell layer responsible for most cell divisions is located in contact with the connective tissue, i.e. next to the external basal lamina.

32. Epithelial Components of the Gingiva
The junctional epithelium is more permeable than the oral or sulcular epithelium. It serves as the preferential route for the passage of bacterial products from the sulcus into the connective tissue and for fluid and cells from the connective tissue into the sulcus.
Arrows indicate path taken by cells and fluids between the sulcus and the gingival connective tissue

33. Epithelial Components of the Gingiva
The term epithelial attachment: refers to the attachment apparatus, i.e. the internal basal lamina and hemidesmosomes, that connects the junctional epithelium to the tooth surface. This term is not synonymous with junctional epithelium which refers to the entire epithelium.

34. Gingival blood supply
The gingival blood supply originates from blood vessels in the periodontal ligament, the marrow spaces of the alveolar process and supraperiosteal blood vessels.
These vessels in turn supply major capillary plexuses that are located in the connective tissue adjacent to the oral epithelium and the junctional epithelium.
PL, vascular supply from periodontal ligament
SP, supraperiosteal blood supply

35. Gingival blood supply

36. Gingival blood supply

37. Gingival inervation
Branches of the trigeminal nerve provide sensory and proprioceptive functions.
In addition, autonomic nerve endings are associated with the vasculature.