Dr Jamal NaimPhD in Orthodontics

Oral Mucosa

Gingiva

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

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.

Mucogingival junction

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.

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).

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.

Gingiva

GingivaMorphologically gingiva is divided into:

1. Attached gingiva

2. Free gingiva

3. Gingival sulcus

4. 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

GingivaDiagrammatic view of gingivaAB, 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;

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-.

Attached gingiva

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.

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.

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.

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

Attached gingiva• The attached gingiva depressed between the

eminencies of the sockets forming grooves called

interdental grooves

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).

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.

Gingival sulcus• This is a defense reaction against bacteria and their

toxins which present in the gingival sulcus.

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.

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

Interdental papilla

• In cases where no contact point (e.g. diastema) the

interdental papilla is reduced in height.

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.

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).

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.

Epithelial Components of the Gingiva

These epithelia differ from one another in their function and,

therefore, in some of their histological characteristics.

1. oral epithelium:

It is the stratified, squamous keratinized epithelium.

2. 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.

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 tissueGS, gingival sulcusPKE, parakeratinized epithelium

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.

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.

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

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.

Gingival blood supplyThe 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

Gingival blood supply

Gingival blood supply

Gingival inervation

Branches of the trigeminal nerve provide sensory and

proprioceptive functions.

In addition, autonomic nerve endings are associated with

the vasculature.