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.