Oral Mucosa

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Oral Mucosa
Dr Jamal Naim PhD in Orthodontics
Cont. 4
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Junctions in the Oral Mucosa

• Junctions in the oral mucosa are lines or
  surfaces, where two different types of mucosa
  meet each other.
• Within the oral mucosa there are three junctions
• Mucocutaneous junction the site of transition
  between skin and mucous membrane.
• Mucogingival junction between gingiva and
  alveolar mucosa
• Dentogingival junction between tooth and free
  gingiva

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Lip epithelium

• Formed of three surfaces
• lining mucosa
• transitional zone (vermilion)
• skin side.
• The junction between the skin
• and the oral mucosa at the
• transitional zone is called
• mucocutaneous junction

skin side
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Transitional zone

• Lying between lining mucosa and skin side of lip.
• Present only in human race and represented as red
  zone called vermilion zone.
• The line separating it from the skin side is the
  vermilion border (mucocutaneous junction)
• It is covered by stratified squamous epithelium
  with thin layer of keratin.

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Oral Mucosa
Dr Jamal Naim PhD in Orthodontics
Gingiva
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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.

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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.

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Gingiva
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Mucogingival junction
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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.
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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).
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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

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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
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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-.

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Attached gingiva
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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 dont denote always
  inflammation.

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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.

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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.

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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

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Attached gingiva

• The attached gingiva depressed between the
  eminencies of the sockets forming grooves called
  interdental grooves

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Free gingiva

• The free gingiva is a relatively mobile tissue
  surrounding the gingival sulcus. It 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 is freely movable and extends to the bottom of
  the gingival sulcus or slightly below (Its length
  1-1.5 mm).
• It tapers to a knife edge (gingival margin).

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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.

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Gingival sulcus

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

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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.

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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
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Interdental papilla

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

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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.

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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).

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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.
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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.

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