Flashcards in Oral Cavity Deck (310)
What are the symptoms of xerostomia?
Mucosa: dry, glossy, atrophic changes
Tongue: glossitis, fissured, red, papilla atrophy
Periodontitis, candidiasis, halitosis
Difficulty in speech and swallowing
What are some treatments for xerostomia?
Inc. water intake
Treat underlying condition
Chew gum i.e. trigger receptors
What are the 5 functions of the oral mucosa?
1. Mechanical protection: compression, shearing
2. Barrier: bacteria, toxins, antigens
3. Immunological defence: humoral, cell-mediated
4. Lubricate saliva
5. Innervation: touch, pain, taste
What are the 3 functional classifications of oral mucosa?
Describe the masticatory mucosa
Area: high compression and friction; gingivae, hard palate
Highly keratinised, thick lamina propria
Describe lining oral mucosa
Area: mobile and distensible; cheeks, lips, alveolar mucosa, floor of mouth, ventral tongue, soft palate
Non-keratinised, loose lamina propria
Describe specialised oral mucosa
Area: dorsal surface of tongue (taste buds); vermilion of lips (transition between skin and oral mucosa)
What are the 4 layers of oral mucosa?
Deep to superficial
2. CT (lamina propria)
3. BM (basal lamina)
4. Stratified squamous epithelium
Compare keratinised, non-keratinised and parakeretinised stratified squamous epithelium
Keratinised: non-viable cells w/o nuclei, filled with keratins (stratum corneum)
Non-keratinised: viable cells w/ nuclei (no stratum corneum)
Parakeratinised: mix of non-viable cells w/o nuclei, apoptotic cells with shrivelled nuclei
Describe the layers of keratinised stratified squamous epithelial
1. Stratum basale: resting on BM, stem and TA cells
2. Stratum spinosum: large, round, prickly appearance due to desmosomes, produce keratin
3. Stratum granulosum: keratohyaline granules, larger, flatter
4. Stratum corneum: keratinised, mechanical protection, filled with keratins, no desmosomes, sheds off
Describe the layers of non-keratinised stratified squamous epithelium
1. Stratum basale: resting on BM, TA and stem cells, give rise to other layers
2. Stratum spinosum: prickly, larger, rounder, produce keratins
3. Stratum intermedium: larger, flatter, no keratohyaline granules
4. Superficial layer: nuclei present, no desmosomes, sheds off
What are keratins?
Fibrous structural proteins composed of intermediate filaments found in all epithelia
What is the function of the basal lamina?
Mechanical adhesion between epithelium and CT
Barrier between them
What are the 2 layers of the basal lamina?
Lamina lucida: made of laminin, adjacent to epithelia
Lamina densa: made of collagen T4, adjacent to CT
How does the basal lamina link CT to epithelial?
What are the 2 layers of lamina propria?
1. Superficial: thin, loosely arranged collagen
2. Deep: thick parallel bundles of collagen
What cells and structures are present in the lamina propria?
Cells: collagen, elastin, oxytalan fibres, proteoglycans - glycoproteins, macrophages, lymphocytes, mast cells, fibroblast producing ECM
Structures: blood vessels, nerve endings
Describe sulcular epithelium
Not in direct contact with enamel
What is the gingival sulcus?
Natural space between tooth and free gingiva
Describe junctional epithelium
Seals off underlying CT and bone
Direct contact with enamel via hemidesmosomes
Why is the junctional epithelium permeable?
Allows tissue fluid and immune cells to pass through into gingival sulcus for defence against invading OB
Explain how plaque formation damages the mucosa
Plaque causes recruitment of inflammatory cells, initially limited and little neutrophil emigration
As gingivitis continues; heavy neutrophil emigration, gingival crevice enlarged, extensive subgingival plaque
Periodontitis: gingival recession with fibrosis in CT, extension of subgingival plaque, apical migration and ulceration of junctional epithelium, alveolar bone resorption and periodontal ligament loss
What are the 3 main parts of a tooth?
1. Root: below gum line; dentine covered by cementum
2. Crown: visible part; dentine covered by enamel
3. Pulp: centre of tooth, blood and nerve supply
What is the cemento-enamel margin/junction?
Border where enamel and cementum meet
What is the enamel-dentine junction?
Border between enamel and dentine
What are ameloblasts and odontoblasts?
Ameloblasts: enamel secreting cells, move from EDJ to surface
Odontoblasts: dentine secreting cells, move from EDJ to pulp
What are the 3 components of enamel?
1. Hydroxyapatite crystals
2. Organic material: amelogenin, enamelin
3. Little water
What are some of the properties of enamel?
Derived from ectoderm
Can't repair self: some capacity to remineralise
Low tensile strength
Hardest biological tissue
High modulus of elasticity
Semi-permeable membrane: allows ions from salvia in, ionic substitution
What is the function of enamel?
Protective: withstand shearing and impact, resist abrasion