structure of Periodontium; gingiva semester 1 Flashcards
name the structure of periodontium
composed of 4 structure;
- gingiva
- cementum
- periodontal ligament
- alveolar bone
Describe the composition and functions of epithelial tissue
characteristic of epithelium:
* Covers outer surface of body (skin)
* Lines cavities such as mouth, stomach, intestines (called mucosa)
* Skin and oral cavity covering (mucosa) is composed of stratified squamous epithelial cells
functions:
* Protection- protect underlying tissue from mechanical injury, harmful chemicals, invading bacteria and from excessive loss of water
* Sensation- sensory nerve endings found in skin, eyes, ears, nose, tongue, etc.
* Secretion- secrete chemical substances including enzymes, hormones and lubricating fluids
* Friction reduction- barrier to underlying connective tissue
Explain the two types of epithelial cell attachment (junctions)
Attachment of epithelial cells
* Provides strength to withstand mechanical forces
* Forms a protective barrier
Desmosome
* Connects two neighbouring epithelial cells together
* A cell-to-cell connection
* Important cell junction in gingival epitheliu
– Hemidesmosome
* Connects epithelial cells to the basal lamina
* A cell to basal lamina connection
* Important cell junction in gingival epitheliu
explain connective tissues
Basal Lamina
* Thin, tough sheet that separates epithelial tissue from underlying
connective tissue
– Types of connective tissue
* Cartilage
* Bone
* Bone marrow
* Tonsils and lymph nodes
* Fat
* Dental tissues (cementum, dentine, pulp)
explain keratinisation
Process in which cytoplasm of outermost epithelial cells is replaced by keratin making it stronger and waterproof.
Keratinised epithelial cells
* No nuclei
* Form tough, resistant layer
* Masticatory mucosa, which includes gingiva
and hard palate (roof of mouth), and oral
epithelium
Non-keratinised epithelial cells
* Have nuclei
* Act as cushion against mechanical forces
* Junctional and sulcular epithelium, floor of mouth, vestibule, inside of cheeks, soft palate
and lips
blood supply
Epithelial tissues do not contain blood vessels
– Nourishment obtained from underlying blood vessels in
connective tissue
Describe the interface between the oral epithelium and connective tissue
Interface
* Connection between oral epithelium
and the connective tissue
* Appear as ridges, known as ‘rete pegs’
extend from connective tissue into
epithelial layer
Characteristics of Interface:
* Increases surface area between the two
tissues
* Increases strength between the two tissues
* Decreases distance between the blood
supply
(in connective tissue) and the epithelium
Blood supply carried through connective
tissue ‘papilla’
Rete pegs found in healthy attached gingiva
giving stippled appearance
Describe the structure and function of junctional epithelium
Epithelium that forms the base of the
sulcus and joins the gingiva to the tooth
surface by hemidesmosomes
– Easiest point of entry for bacteria to
invade connective tissue of gingiva
– Gingiva has ability to repair itself
– Attaches gingiva to enamel and/or
cementum of tooth
– Forms seal at base of gingival sulcus or
pocket
– Serves as a protective barrier between
plaque (biofilm) and connective tissue of
the periodontium
gingival epithelium
– Gingival Epithelium
* Specialised stratified squamous epithelium
* Functions well in wet environment
– 3 Anatomical areas
* Oral epithelium
* Sulcular epithelium
* Junctional epithelium
oral epithelium
Covers the outer surface of the free
gingiva and attached gingiva
– Extends from the crest of the gingival
margin to the mucogingival junction
explain gingival fibres and describe the functions
Characteristics
* Rope-like
* Located coronal (toward crown) to the crest
of the alveolar bone
– Functions
* Attaches JE to tooth
* Attaches free gingiva to cementum and bone
* Withstands frictional forces (holding free
gingiva against the tooth)
* Controls positioning (connects adjacent
teeth)
describe the gingiva fibres groups
Gingival Fibre Groups
– Circular: encircles the tooth like a ring
– Dentogingival: attaches gingiva to
teeth
– Dentoperiosteal: attaches gingiva to
bone
– Alveologingival: periosteum of
alveolar crest into gingival connective
tissue
– Transeptal: Cementum from one
tooth, over the alveolar crest to
cementum of the adjacent tooth
sulcular epithelium
Epithelial lining of sulcus
– Extends from crest of gingival margin
to the coronal edge of the Junctional
Epithelium (JE)
– Forms shallow ‘pocket’ or ‘cuff’
around the tooth (usually 0.5 to 3 mm
in depth)
* with periodontal disease, this space
deepens and the tissue becomes
ulcerated
