THE GINGIVA
-part of the oral mucosa that covers the alveolar process of the jaws and neck of the teeth.
Macroscopic features:
-divided anatomically into: Marginal, Attached and Interdental Gingiva.
1. Marginal Gingiva - terminal edge or border of the gingiva sorrounding the teeth in collar-like or
knife-edge-edge fashion.
-Free gingival groove - a shallow linear depression demarcating marginal from attached
gingiva.
-Usually about 1 mm wide, forming the soft tissue wall of the gingival sulcus.
-Gingival Sulcus - a shallow crevice or space around a tooth bounded by the surface of the
tooth on one side and the epithelial lining the free margin of the gingiva on the other. A v-shaped
and barely permits entrance of periodontal probe. Under absolutely normal conditions, the depth is
0mm. Probing depth is 2-3 mm or 1-3 mm on other books.
2. Attached Gingiva - continuous with the marginal gingiva. Firm, resilient and tightly bounded to the underlying periosteum of the alveolar
bone.
-Mucogingival Junction - demarcated attached gingiva from the loose and movable alveolar mucosa.
-the width of the attached gingiva is the distance between the mucogingival junction and the projection on the
external suface of the bottom of the gingival sulcus or the periodontal pocket.
3. Interdental gingiva - occupies the gingival embrasure. Can be pyramidal or col shape. If diastema is present, the
gingiva is firmly bound over to the interdental bone and forms a smooth, rounded surface without interdental papilla.
Microscopic features:
Gingival epithelium
- our gingiva is consists of central core of connective tissue covered by stratified squamous epithelium.
1. Outer or Oral Epithelium - it covers the crest and outer suface of the marginal gingiva and attached gingiva. This consists of
keratinized stratified squamous epithelium. It extends from the mucogingival junction to the gingival margin.
Stratum basale - basal layer
Stratum spinosum - spinous layer
Stratum granulosum - granular layer
Stratum corneum - cornified layer
2. Sulcular Epithelium - lines the gingival sulcus. A thin nonkeratinized stratified squamous epithelium that extends from the
coronal limit of the junctional epithelium to crest of the gingival margin. It is important because it may act as semipermeable
membrane in injurious bacterial products.
3. Junctional Epithelium - collar-like band of nonkeratinized stratified squamous epithelium. It consists of basal lamina or basement membrane
that attached to connective tissue. Basal lamina consist of lamina densa and lamina lucida to which hemodesmosomes are attached.
4 types of surface differentiation
1. Keratinization - it involves the sequence of biochemical and morphologic events occur in cell as it migrates from basal layer to keratinized
suface. Surface cells from scales of keratin and lose their nuclei.
2. Parakeratinization - cells of superficial layer retain their nuclei.
3. Nonkeratinization - in which cells of surface layers are nucleated and no signs of keratinized.
In oral mucosa, the most keratinized is the Palate and least are the Gingiva, Tongue and Cheek.
Cell types:
1. Keratinocyte - the principal cell type of the oral and gingival epithelium, as well as other stratified squamous epithelia. Constitute about 90%
or more of gingival epithelium.
2. Melanocytes - dendritic cells located in the basal and spinous layers of the gingival epithelium. They synthesize melanin in organelles called
premelanocytes and melanosomes.
3. Langerhans Cells - dendritic cells located among keratinocytes at all suprabasal layers. They contain elongated granules and are considered to
be macrophages with possible antigenic properties. They are found in oral epithelium and in smaller amount in sulcular epithelium but absent in
junctional epithelium.
4. Merkel Cells - located in the deeper layers of epithelium and are the terminals of the nerve fibers, connected to adjacent cells by desmosomes.
They have been identified as tactile receptors.
Sulcular Fluid
- gingival sulcus contains normal fluid which seeps to it from the gingival connective tissue though thin circular wall. It is believed to:
1. Cleanse material from sulcus
2. Contains plasma protein which may improve adhesion of epithelial attachment of tooth.
3. It possess antimicrobial properties.
4. Exert antibody in defense of gingiva.
-part of the oral mucosa that covers the alveolar process of the jaws and neck of the teeth.
Macroscopic features:
-divided anatomically into: Marginal, Attached and Interdental Gingiva.
1. Marginal Gingiva - terminal edge or border of the gingiva sorrounding the teeth in collar-like or
knife-edge-edge fashion.
-Free gingival groove - a shallow linear depression demarcating marginal from attached
gingiva.
-Usually about 1 mm wide, forming the soft tissue wall of the gingival sulcus.
-Gingival Sulcus - a shallow crevice or space around a tooth bounded by the surface of the
tooth on one side and the epithelial lining the free margin of the gingiva on the other. A v-shaped
and barely permits entrance of periodontal probe. Under absolutely normal conditions, the depth is
0mm. Probing depth is 2-3 mm or 1-3 mm on other books.
2. Attached Gingiva - continuous with the marginal gingiva. Firm, resilient and tightly bounded to the underlying periosteum of the alveolar
bone.
-Mucogingival Junction - demarcated attached gingiva from the loose and movable alveolar mucosa.
-the width of the attached gingiva is the distance between the mucogingival junction and the projection on the
external suface of the bottom of the gingival sulcus or the periodontal pocket.
3. Interdental gingiva - occupies the gingival embrasure. Can be pyramidal or col shape. If diastema is present, the
gingiva is firmly bound over to the interdental bone and forms a smooth, rounded surface without interdental papilla.
Microscopic features:
Gingival epithelium
- our gingiva is consists of central core of connective tissue covered by stratified squamous epithelium.
1. Outer or Oral Epithelium - it covers the crest and outer suface of the marginal gingiva and attached gingiva. This consists of
keratinized stratified squamous epithelium. It extends from the mucogingival junction to the gingival margin.
Stratum basale - basal layer
Stratum spinosum - spinous layer
Stratum granulosum - granular layer
Stratum corneum - cornified layer
2. Sulcular Epithelium - lines the gingival sulcus. A thin nonkeratinized stratified squamous epithelium that extends from the
coronal limit of the junctional epithelium to crest of the gingival margin. It is important because it may act as semipermeable
membrane in injurious bacterial products.
3. Junctional Epithelium - collar-like band of nonkeratinized stratified squamous epithelium. It consists of basal lamina or basement membrane
that attached to connective tissue. Basal lamina consist of lamina densa and lamina lucida to which hemodesmosomes are attached.
4 types of surface differentiation
1. Keratinization - it involves the sequence of biochemical and morphologic events occur in cell as it migrates from basal layer to keratinized
suface. Surface cells from scales of keratin and lose their nuclei.
2. Parakeratinization - cells of superficial layer retain their nuclei.
3. Nonkeratinization - in which cells of surface layers are nucleated and no signs of keratinized.
In oral mucosa, the most keratinized is the Palate and least are the Gingiva, Tongue and Cheek.
Cell types:
1. Keratinocyte - the principal cell type of the oral and gingival epithelium, as well as other stratified squamous epithelia. Constitute about 90%
or more of gingival epithelium.
2. Melanocytes - dendritic cells located in the basal and spinous layers of the gingival epithelium. They synthesize melanin in organelles called
premelanocytes and melanosomes.
3. Langerhans Cells - dendritic cells located among keratinocytes at all suprabasal layers. They contain elongated granules and are considered to
be macrophages with possible antigenic properties. They are found in oral epithelium and in smaller amount in sulcular epithelium but absent in
junctional epithelium.
4. Merkel Cells - located in the deeper layers of epithelium and are the terminals of the nerve fibers, connected to adjacent cells by desmosomes.
They have been identified as tactile receptors.
Sulcular Fluid
- gingival sulcus contains normal fluid which seeps to it from the gingival connective tissue though thin circular wall. It is believed to:
1. Cleanse material from sulcus
2. Contains plasma protein which may improve adhesion of epithelial attachment of tooth.
3. It possess antimicrobial properties.
4. Exert antibody in defense of gingiva.
