MADI -OA lecture 6

Where does the basement membrane lie

between epithelium and lamina propria (CT)

What does the oral mucosa consist of

stratified squamous epithelium overlying lamina propria (CT)

basement membrane lies between the epithelium and lamina propria

3 types of oral mucosa

Lining mucosa, masticatory mucosa, specialized mucosa

Lining mucosa region (6)

Buccal , labial, alveolar mucosa, ventral

surface of tongue, floor of mouth, soft palate

Lining mucosa clinical appearance (4)

Soft surface texture, moist, stretchable, compressible

Lining mucosa function

Acts as a cushion for underlying structures

Histology- what type of epithelium is lining mucosa?

Non-keratinized stratified squamous epithelium

Histology- lining mucosa rete ridges and connective tissue papillae

It is generally smoother with fewer and less-pronounced rete ridges and connective tissue papillae.

Histology- what do elastic fibers in the lamina propria and submucosa provide to the tissue?

They provide the tissue with a moveable base.

Masticatory mucosa region (3)

attached gingiva, hard palate, dorsal surface of tongue

Masticatory mucosa clinical appearance (2)

rubbery surface texture & resilient, firm base

Masticatory mucosa function

mastication resiliency

Histology- what type of epithelium is found in masticatory mucosa?

Orthokeratinized and parakeratinized stratified squamous epithelium

Histology- masticatory mucosa rete ridges and connective tissue papillae

Many rete ridges and connective tissue papillae

What is the characteristic of the submucosa in masticatory mucosa?

Only a thin layer of submucosa (or none)

Specialized mucosa location

dorsal and lateral surface of tongue

Specialized mucosa clinical appearance

associated with the lingual papillae

Specialized mucosa function (2)

taste receptors, papillary architecture

Histology- specialized mucosa keratinization (4)

-does not display uniform level of keratinization

-some papillae keratinized, some partial

-heterogenous pattern is complex

-discrete structures of epithelium and lamina propria

3 epithelium types

Non-Keratinized, orthokeratinized, parakeratinized

What type of mucosa is non-keratinized epithelium associated with

superficial layers of lining mucosa

provides covering for moist areas

3 layers of non-keratinized epithelium

basal, intermediate, and superficial

Non-keratinized epithelium- basal layer (4)

-single thin layer of cuboidal cells

-overlying basement membrane above lamina propria

-responsible for mitosis

-produce basal lamina of basement membrane

Non-keratinized epithelium- intermediate layer (3)

-larger cells superficial to basal layer

-makes up bulk

-rapid regeneration of cells for response to injury

Non-keratinized epithelium- superficial layer

consists of largest cells with shedding outer squames

What types of oral mucosa is associated with orthokeratinized epithelium

masticatory mucosa and specialized mucosa

4 layers of orthokeratinized layer

basal

prickle

granular

keratin

Orthokeratinized epithelium- basal layer (3)

deepest layer

undergoes mitosis

produces the basal lamina of the basement membrane

Orthokeratinized epithelium- prickle layer (3)

superficial to basal layer

bulk of keratinized epithelium

cells migrate here and lose mitosis ability

Orthokeratinized epithelium- granular layer (2)

flat, stacked cells

form a chemical precursor for keratin

Orthokeratinized epithelium- keratin layer (4)

most superior layer

flat cells with no nuclei

protective and waterproof

outer squames flatten and shed

What type of oral mucosa is associated with parakeratinized epithelium

masticatory mucosa and specialized mucosa

Parakeratinized epithelium

-immature form of orthokeratinized epithelium

-unique to oral cavity

-all the same layers as orthokeratinized epithelium

-granular layer may be indistinct or absent

-main difference: when superficial layer is shed, parakeratinized squames still have nucli

What is a unique histological feature of the oral cavity?

Parakeratinized epithelium

What is the main difference between the squames of parakeratinized and orthokeratinized epithelium?

Parakeratinized squames still contain nuclei when shed, unlike orthokeratinized squames.

What is the lamina propria?

Connective tissue proper region of oral mucosa

What type of collagen fibers is the main group in the lamina propria?

Type I collagen fibers

2 layers of lamina propria

papillary- superficial, loose CT

dense- deeper, dense

What is the most common cell type found in the lamina propria?

Fibroblasts

What is nicotine stomatitis?

A condition resulting from the effects of smoking or spit tobacco on the vestibule.

Fibrosis

Keratinized tissue that has undergone further keratinization in the attached gingiva

the later stages of advanced periodontal

disease

Hyperkeratinization (4)

-thickening of the outer layer of the skin or mucous membranes due to an increase in keratin

-excessive formation of keratin in response to frictional or chemical trauma

-common in non-keratinized buccal mucosa

-can be revered if irritation is removed

What causes hyperkeratinization

chronic heat production on the hard palate from hot liquids, smoking, or spit tobacco on vestibule

Labial/ buccal mucosa- clinical appearance

lining mucosa

opaque pink, shiny, moist with possible areas of mealnin pigment and fordyce spots

Labial/ buccal mucosa- histologic features

-epithelium: thick & non-keratinized

-lamina propria: irregular and blunt CT papillae, some elastic fibers, extensive vascular supply

-submucosa: adipose CT and minor salivary glands

1 multiple choice option

Alveolar mucosa- clinical appearance

lining mucosa

reddish-pink, shiny, moist, extremely mobile

Alveolar mucosa- histological features

-epithelium: thin, non-keratinized

-lamina propria: CT papillae sometimes absent, mini elastic fibers, extensive vascular supply

-submucosa: minor salivary glands and many elastic fibers with loose attachment to muscle or bone

1 multiple choice option

Ventral tongue/ floor of mouth- clinical appearance (6)

reddish-pink, shiny, compressible, vascular blue areas, variable mobility

Ventral tongue/ floor of mouth- histologic features

-epithelium: extremely thin, non-keratinized

-lamina propria: tongue- extensive vascular supply, numerous CT papillae, some elastic fibers, minor salivary glands, extremely thin and firmly attached to muscle. floor- broad CT papillae

-submucosa: tongue- extremely thin and firmly attached to muscle. floor- adipose CT with submandibular and sublingual salivary glands, loosely attached to bone or muscle

Soft palate- clinical appearance (3)

lining mucosa

-deep pink with yellow hue and moist surface, compressible and extremely elastic

Soft palate- histologic features

-epithelium: thin and non-keratinized

-lamina propria: thick with numerous CT papillae and a distinct elastic layer

-submucosa: extremely thing with adipose CT and minor salivary glands, with a firm attachment to underlying muscle

Hard palate- clinical appearance (6)

masticatory mucosa

pink, immobile and firm medial zone

palatal rugae and median palatine raphae, cushioned lateral zones

Hard palate- histological features

-epithelium: thick, orthokeratinized; medial zone is part of the mucoperiosteum to the underlying bone

-lamina propria: medial zone is part of the mucoperiosteum to underlying bone, along with palatal rugae and raphe

-submucosa: present only in lateral zones, anterior part has adipose CT and posterior part has minor salivary glands; absent in medial zone along with ruegue and raphae

Attached gingiva- clinical appearance (5)

masticatory mucosa

opaque pink, dull and firm

immobile with possible areas of melanin pigment and varying amounts of stippling (lost w/ age and perio)

Attached gingiva- histological features

-epithelium: thick keratinized (mostly para-, some ortho-); part of mucoperiosteum to underlying bone

-lamina propria: tall narrow CT papillae, extensive vascular supply; part of mucoperiosteum to underlying bone

-submucosa: not present

Mucoperiosteum

type of oral mucosa in which the lamina propria is directly fused to the periosteum of the bone — meaning no submucosa is present.

4 properties of the tongue

-striated muscle covered by oral mucosa

-mobile anterior with bulky & less mobile posterior

-dorsal surface has both masticatory and specialized mucosa

-specialized mucosa on dorsal and lateral associated with lingual papillae (4 types)

Sulcus terminalis

divides dorsal surface of tongue into anterior 2/3 and posterior 1/3

4 types of lingual papillae

filiform

fungiform

foliate

circumvallate

filiform lingual papillae

-clinical appearance: most common, fine pointed cones

-histological features: thick keratinized epithelium, no taste buds

-function: mechanical

fungiform lingual papillae

-clinical appearance: less, mushroom shaped, small red dots

-histological features: thin keratinized epithelium, with taste buds

-function: taste

foliate lingual papillae

-clinical appearance: 4-11 vertical ridges on posterior lateral surface

-histological features: leaf-shaped structure of keratinized epithelium, with taste buds

-function: taste

circumvallate lingual papillae

-clinical appearance: 7-15 mushroom shaped, anterior to sulcus terminalis

-histological features: similar to fungiform, deep in tongue, has taste buds and saliva glands

-function: taste

geographic tongue (5)

-red/ pale pink- white patches on body of tongue

-patches change shape

-correspond to groups of filiform undergoing changes from parakeratinized (red) to orthokeratinized (white) epithelium

-can be sore or burning (not always)

-no treatment needed

black hairy tongue (3)

-shedding of epithelium does not occur

-thick layer of dead cells and keratin builds on tongue, which becomes strained by tobacco, medications, or chromogenic bacteria

-might result from fungal overgrowth

Melanin

pigment formed by melanocytes;

they are evenly distributed throughout the oral

mucosa

Hard palate turnover time

24 days (slowest)

Floor of mouth turnover time

20 days

Buccal and labial mucosa turnover time

14 days

Attached gingiva turnover time

10 days

Taste bud turnover time

10 days

Junctional epithelium turnover time

4-6 days (fastest)

Which oral tissue has the fastest turnover time (4-6 days)

junctional epithelium

3 multiple choice options

Which oral tissue has the slowest turnover time (24 days)

hard palate

2 multiple choice options

Oral mucosa repair

like skin repair, but a moist clot is formed rather than a dry clot

What triggers the inflammatory response during the repair process?

Blood products from the injured area form a clot

Why must the clot be retained in the first days of repair?

The clot acts as a guide to form a new epithelial surface.

What do fibroblasts produce during the repair process?

Fibroblasts migrate to produce immature connective tissue known as granulation tissue.

What replaces granulation tissue in the repair process?

Granulation tissue is later replaced by scar tissue.

How does replacement tissue differ from granulation tissue?

Replacement tissue has more fibers and fewer blood vessels.

Aging: clinically (5)

Reduction of stippling on the attached gingiva

Increase of fordyce spots on the labial and buccal mucosa

enlargement of the major veins (lingual varicosities)

reduction of lingual papilla and associated taste buds

hyposalivation

Aging: microscopically (5)

-decrease thickness and number of rete ridges

-decrease keratinization of masticatory mucosa in attached gingiva

-slower turnover

-thicker collagen fibers, change in elastic fibers, decrease fibroblasts

-increase repair time

What tissue may become abundant in healing and interfere with repair

granulation tissue

3 possible sources of injury to oral mucosa

physical, chemical, infectious

how long does healing usually take in oral mucosa

2 weeks

a longer delay for follow up is not recommended

Gingival Recession - age or disease

More sign of disease than age

-usually disease or longtime bad habit

Angular cheilitis

creasing and then cracking at the labial commissure

thought to be a sign of disease in the aged

What tissue is the most important for dental professionals to know and understand

gingival tissue

Healthy gingival tissue

effective barrier to the barrage of insults to deeper periodontal tissue

Not healthy gingival tissue

provides a gateway for periodontal disease to advance into the deeper tissue of periodontium

What is attached gingiva?

Masticatory mucosa that tightly adheres to the alveolar process; surrounds the roots of the teeth.

What is interdental gingiva?

Tissue between adjacent teeth adjoining the attached gingiva.

What are interdental papillae?

Tissue that fills in the area between the teeth apical to their contact areas to prevent food impaction.

What is the col in gingival anatomy?

A nonvisible concave shape between the facial and lingual gingival surfaces, apical to the contact area (non-keratinized).

What is marginal gingiva?

Continuous with the attached gingiva, follows the scalloped pattern established by the contour of the CEJ; unattached and unstippled.

Attached gingiva histology (5)

-has an overlying thick layer of mostly parakeratinized stratified squamous epithelium

-obscures extensive vascular supply in lamina propria

-tall narrow CT papillae from lamina propria alternates with rete ridges = stippling look

-epithelium and lamina propria interlock

-firm and mobile

marginal gingiva histology (5)

-has an overlying surface layer of only orthokeratinized stratified squamous epithelium

-tall narrow papillae

-lamina propria is continuous with lamina propria of the gingival tissue facing tooth

-not attached to underlying alveolar process= firm but mobile

-col is non-keratinized

What is the only area that is non-keratinized

col

Supracrestal tissue attachment (4)

-combines heights of suprabony soft tissue around tooth

- ~2.04mm

-natural seal to keep perio disease from going deep down

-evaluate during probing

What 2 tissues give you the biological width at the dentogingival junction

supracrestal tissue attachment

length of the epithelial attachment of the junctional epithelium (0.97mm)

lamina propria attachment length (1.07mm)

total of 2.04mm