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ORAL MUCOSA

Presented by

Hanaa AlyProfessor of Oral Biology

Faculty of Dentistry

Alexandria UniversityProf. Hanaa Aly

Masticatory MucosaFirm & immobile mucosa; pink in color; keratinized& functions during mastication.

• Gingiva

• Covering of hard palate

Gingiva:

is that part of oral mucosa that surrounds the neck of teeth

and cover alveolar process.

Morphologically it is divided into 3 areas or zones:

1- free or marginal gingiva

2- attached gingiva

3- interdental papilla

Prof. Hanaa Aly

1-boundaries of Free gingiva ( marginal gingiva):• coronally by gingival margin,

• apically by free gingival groove

• inner margin by gingival sulcus

• outer surface by vestibular and oral cavities

2-boundaries of Attached gingiva:Between free gingiva and alveolar mucosa

Separated from alveolar mucosa by mucogingival junction

Wider in anterior (5-6mm) than posterior (3mm)

3- boundaries of Interdental papillawedge shaped, occupies the space between to adjacent teeth apical to contact area

Prof. Hanaa Aly

Ten Cate’s 2008 p350

What is the mucogingival junction ?Prof. Hanaa Aly

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Stippling of Attached gingiva (orange(orange--peel appearancepeel appearance): ): •• Portions at the epithelium appear to be elevated , & between the elevations Portions at the epithelium appear to be elevated , & between the elevations there are shallow depressions .CT papilla project into the elevationsthere are shallow depressions .CT papilla project into the elevations

•• Characteristic of normal gingivaCharacteristic of normal gingiva•• Functional adaptation to mechanical impactsFunctional adaptation to mechanical impacts•• Absence of stippling means edemaAbsence of stippling means edema

•• Gingival sulcusGingival sulcus

• shallow groove between the tooth & normal gingiva• Its depth = 0.5 - 3 mm• Contains gingival fluid in which desquamated epithelial cells & neutrophils exist

• Interdental grooves:•• Slight vertical folds of the gingiva eSlight vertical folds of the gingiva extends vertically toward interdental papilla and correspond to depressions between the roots of adjacent teeth

Prof. Hanaa Aly

age and sex:(a) Males tend to have more heavily stippled gingiva than females.

(b) In younger females the connective tissue is finely textured than in males.

(c) Females' cells contain a large chromatin particle adjacent to the nuclear membrane ( Barr's body).

Prof. Hanaa Aly

The interdental gingiva:

It is the continuation of the attached and free gingiva in the interdental

spaces between the teeth. It is attached to the crest of the alveolar bone

and supported by it.

Facially and lingually the interdental gingiva is triangular, the base of the

triangle extends from the margin of the gingiva at the center of one tooth

to the center of the next. The interdental papilla is the free part of the

interdental gingiva reaching up to the contact area

3 dimension of IDP:

Anterior teeth (pyramidal)

Posterior teeth (tent shape) Prof. Hanaa Aly

Interdental ColInterdental Col

interproximal to vestibular &interproximal to vestibular &

oral cavity surfaces of IDPoral cavity surfaces of IDP

a valleya valley--like depression (concave area) between the buccal & lingual raised margins of IDPlike depression (concave area) between the buccal & lingual raised margins of IDP

Lies directly below the contact points of posterior teeth(broad contact areas)Lies directly below the contact points of posterior teeth(broad contact areas)

Gingival epith is thin nonkeratinized+ numerous epith ridges +signs of inflammationGingival epith is thin nonkeratinized+ numerous epith ridges +signs of inflammation

By age the col flatten because the vestibular & interdental peaks descend By age the col flatten because the vestibular & interdental peaks descend

Prof. Hanaa Aly

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Histology of the Gingiva:surface epithelium: Is a stratified squamous epithelium containing nonkeratinocytes.

The epithelium: is of three types.

Orthokeratinized epithelium: the stratum corneum consists of flat tightly

packed scales showing no nuclei. This type constitutes 15%.

Parakeratinized epithelium: the stratum corneum retain pyknotic nuclei

This type constitutes 75%.

Nonkeratinized epithelium: This type accounts for about 10%.

gingival sulcus, the epithelium of the col and the junctional epithelium

Prof. Hanaa Aly

Turnover time

The turnover time of the gingival epithelium varies from 41-57 days.

Definition :

It is the time necessary for the epithelial cell

to divide and migrate through the entire epithelium

to be desquamated at the surface.

Prof. Hanaa Aly

•• Microscopic appearance of the gingivaMicroscopic appearance of the gingiva

Dense collagenous lamina propria Dense collagenous lamina propria

((GingivalGingival LigamentLigament):):

11--Dentogingival fibers (cementum to lamina propria of gingiva)Dentogingival fibers (cementum to lamina propria of gingiva)

22--Alveologingival fibers (bone to lamina propria of gingiva)Alveologingival fibers (bone to lamina propria of gingiva)

33--Circular fibersCircular fibers

44--Dentoperiosteal (cementum to periosteumDentoperiosteal (cementum to periosteum))

study table 12-6 Ten Cate’s 2008, p347 masticatory mucosa

5-Transseptal fibers:Interproximally between 2 teeth

No submucosa (Mucoperiosteum)

Prof. Hanaa Aly

11--Interdental Alveolar Arterioles penetrate ID septaInterdental Alveolar Arterioles penetrate ID septa

22--Supraperiosteal Arterioles facial & lingual surfaces of alveolar boneSupraperiosteal Arterioles facial & lingual surfaces of alveolar bone

33--PDL vessels extend to gingiva & anastomose with capillaries in sulcusPDL vessels extend to gingiva & anastomose with capillaries in sulcus

Blood supply of gingivaBlood supply of gingiva

Lymph vessels of the gingivaLymph vessels of the gingiva“rich network ; along bld vs” to submandibular & submental lymph nodes“rich network ; along bld vs” to submandibular & submental lymph nodes

Nerve supply of the gingivaNerve supply of the gingiva“gingiva is well innervated”“gingiva is well innervated”

Nerve endings: free, Meissner,Krause & Ruffini corpusclesNerve endings: free, Meissner,Krause & Ruffini corpuscles

Any one of these nerve endings responds to most of the Any one of these nerve endings responds to most of the

sensation modalities, heat , cold, touch and pain i.e. they are sensation modalities, heat , cold, touch and pain i.e. they are

polymodalpolymodal

Prof. Hanaa Aly

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Dentogingival junction

•• A unique anatomic feature . A unique anatomic feature .

•• It is the junction between epith & enamel ( the principal seal between oral cavity & underlying tissues)It is the junction between epith & enamel ( the principal seal between oral cavity & underlying tissues)

•• Derived from reduced enamel epithelium & regenerate from adjacent oral epithDerived from reduced enamel epithelium & regenerate from adjacent oral epith

•• Components :Components :

11--gingival epithelium (orthokeratinized or paraparakeratinized str sq epith)gingival epithelium (orthokeratinized or paraparakeratinized str sq epith)

22--sulcular epithelium (nonkeratinized str sq epith)sulcular epithelium (nonkeratinized str sq epith)

33--junctional epitheliu (immature flat cells oriented parallel to tooth surface lying on basal cells)junctional epitheliu (immature flat cells oriented parallel to tooth surface lying on basal cells)

tapered(tapered(33--4 4 layers apically to layers apically to 1515--30 30 layers coronally)layers coronally)

it has outer basal lamina attaches epith to CT; inner basal lamina adheres to tooth surfaceit has outer basal lamina attaches epith to CT; inner basal lamina adheres to tooth surface

differ from outer basal lamina that type IV & VII collagens are not present:it contain amelotindiffer from outer basal lamina that type IV & VII collagens are not present:it contain amelotin

Epithelial attachment Mode of attachment of junctional epithelium:Epithelial attachment Mode of attachment of junctional epithelium:means of attachment on tooth(E or C) consist of inner basal lamina+hemidesmosomesmeans of attachment on tooth(E or C) consist of inner basal lamina+hemidesmosomes

Ultrastructure Ultrastructure of junctional epith:fewer tonofilaments& desmosomes, wide intercellular spaces,presence of junctional epith:fewer tonofilaments& desmosomes, wide intercellular spaces,presence of neutrophils, st basament membraneof neutrophils, st basament membrane

Basal cells undergo cell division high rate(Basal cells undergo cell division high rate(44--6 6 days)days)

;migratory route of cells is coronally parallel to tooth surface then desquamate into gingival sulcus;migratory route of cells is coronally parallel to tooth surface then desquamate into gingival sulcus

Prof. Hanaa Aly

Dentogingival junction

connective tissue component:

How CT determine the epithelial expression?

TWO factors:

1-Lamina propria provide instructive influences

Deep CT possesses only permissive factors

2-Inflammation ?

What is the importance of that junctional epith is in contact with deep CT?

1-to remain undifferentiated

2-to form epithelial attachment

Low level of Inflammation in CT lead to Passive eruption Prof. Hanaa Aly

• What are the four stages of

passive eruption?

• Where is the bottom of the sulcus

&apical end in each stage?

• At what age the first & second

persist?

• Clinical crown? p 309

• Anatomical crown ? p 309

Apical migration of the junctional epithelium on the tooth surface

Orban’s Oral Histology & Embrology pOrban’s Oral Histology & Embrology p308308&&309309

Passive Eruption (shift of DGJ)Passive Eruption (shift of DGJ)

Prof. Hanaa Aly

Avery 3rd ed Oral Development and Histology p252-253

Masticatory mucosa

MUCOPERIOSTEUM :MUCOPERIOSTEUM :

-Gingival region

-Palatine raphe (medianmedian)

-rugae (traction bands ?)

SUBMUCOSA :SUBMUCOSA :

-Anterolateral area “fatty zonefatty zone”

-Posterolateral are “glandular zoneglandular zone”

Incisive papilla:Covered by keratinized mucosakeratinized mucosa

Dense CTDense CT maymay contain

-- nasopalatine duct remnantsnasopalatine duct remnants

-- c a r t i l a g ec a r t i l a g e

-- epithelial pearlsepithelial pearls

Why there are areas of submucosa in hard palate?p347 Ten Cate’s 2008 table 12-6

Prof. Hanaa Aly

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Lining mucosa

(table 12-6 p347 Ten Cate’s 2008)

FIRMLY ATTACHED:

• Soft palate

• Labial & buccal mucosa

• Ventral (inferior) surface of tongue

• Floor of mouth (more permeable to drugs)

• Vestibular fornex

• Alveolar mucos

What is the structure of each?

Where is the thinner & thickest epith?

Where is elastic fibers found?

Prof. Hanaa Aly

LOOSELY ATTACHED:

Ten Cate’s Oral Histology 2008 p 347 table 12-6 &p350 Mucocutaneous junction(vermilion zone)junction bet skin & labial mucosa

• No appenndages

• Few sebaceous glands (crack in cold weather)

• Thin keratinized epith

• Protein in epithelial cells (eleidin) more transparent

• Numerous long CT papillae containing capillary loops (blood close to surface give red coloration)

Intermediate zone (suckling pad)Bet vermilion zone & labial mucosa

Infants

Thickened

Covered by parakeratinized epith

Elastic fibersProf. Hanaa Aly

CLINICAL CLINICAL

FEATURESFEATURES

KERATINIZEDKERATINIZED

Anesthessia Anesthessia

painful?painful?

Biopsy no suture?Biopsy no suture?

NONNON--KERATINIZEDKERATINIZED

Not painful ?Not painful ?

Need suture?Need suture?

Fordyce’s spots:

sebaceous glands appear pale yellow spots

Present in: upper lip; buccal mucosa;

occassionally in alveolar mucosa & dorsum of tongue

Linea alba:

slight whitish ridge occurs along buccal mucosa in occlussal plane

Keratinized

Rough restoration or cheek biting

Ten Cate’s 2008 p 320& 321

Prof. Hanaa Aly

Specialized mucosa(dorsal surface of tongue)

• Anterior 2/3(covered by papillae)

• Posterior 1/3(covered by lymphoid nodules;lingual

tonsils)

Tongue papillae:

• Filiform papillae (masticatory function)

• Funiform papillae (flexibility:taste )

• Circumvallate papillae (taste); (von Ebner glands)

• Folliate papillae (taste)

Mention their distribution on tongue surface?

What is the structure of each under microscope?

Ten Cate’s 2008 p349-350 Prof. Hanaa Aly

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Ten Cate’s 2008 p344-346 found in soft palate; pharynx;

fungiform; circumvallate; folliate papillae

• Barrel shaped

• 30-80 spindle shaped cells

• Basal lamina bet cells & CT

• Taste pore

• 2 types of cells:

Type I(dark; numerous vesicles; adjacent to nerves;junctional complexes)

Type II (supporting cells;large pale nucleus)

Taste buds

Prof. Hanaa Aly

The posterior third of the tongue

irregularly studded with round or oval prominences, lingual follicles.

one or more lymph nodules,

lingual tonsil + the palatine tonsils +pharyngeal tonsils (adenoids)

completes Waldeyer's ring of lymphoid tissue

guarding the entrance of the gastrointestinal and the respiratory tracts.

Prof. Hanaa Aly

(Ten Cate’s 2008 p355-356)

AGE CHANGES OF ORAL

MUCOSA•• Epithelium : thinner ; flattening of epith ridges; more fragileEpithelium : thinner ; flattening of epith ridges; more fragile

•• Fewer Langerhans’ cells & immunity declineFewer Langerhans’ cells & immunity decline

•• Lamina Propria :decrease in cellularity ;increase in collagen (coarser)Lamina Propria :decrease in cellularity ;increase in collagen (coarser)

•• Fordyce’s spots (sebaceous glands) increaseFordyce’s spots (sebaceous glands) increase

•• Minor salivary glands : atrophy Minor salivary glands : atrophy

•• Tongue :reduced # of filiform ; foliate more prominent(smooth, glossy)Tongue :reduced # of filiform ; foliate more prominent(smooth, glossy)

•• Nodular varicose veins (cavier tongue)Nodular varicose veins (cavier tongue)

•• Recession of gingiva & decrease in height of IDPRecession of gingiva & decrease in height of IDP

•• Passive eruptionPassive eruption

Prof. Hanaa AlyProf. Hanaa Aly

Clinical consideration

In Lining mucosa fluid

disperse

Textbooks

• Ten Cate’s Oral Histology 7th ed ch 12 Oral Mucosa 2008

• Avery Oral Development and Histology 3rd ed ch 14 p252-253

ch 15 p263-267

• Orban’s Oral Histology and Embryology 10th ed ch 9 p305,308,310& 314

Prof. Hanaa Aly

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GOOD LUCK

Prof. Hanaa Aly