DH150 The Periodontium (LO4)

What is the lining of the oral cavity called?

oral mucosa

What kind of tissue is the oral mucosa?

stratified squamous epithelium

What are the 3 categories of the oral mucosa?

specialized, masticatory, lining

What is specialized mucosa and where can it be found?

covers the top if the tongue and is adapted to accommodate for taste and sensation

Where is masticatory mucosa found?

gingiva and hard palate

What kind of epithelium is masticatory mucosa?

parakeratinized or keratinized caused by pressure of food

What is the function of masticatory mucosa?

designed to withstand frictional forces such as swallowing and chewing

Is lining mucosa loosely attached or firmly?

loosely

What kind of epithelium is the lining mucosa?

non-keratinized stratified squamous epithelium

Examples of lining mucosa?

buccal & labial mucosa, soft palate, ventral tongue, floor of mouth, vestibular sulcus & alveolar mucosa

What is keratinization?

process by which epithelial cells differentiate or mature

What happens to an epithelial cell as it is more keratinized?

more resistant and tough it is

What is keratinized mucosa?

on its surface a layer of dead cells without nuclei (hard palate)

What is parakeratinized?

on its surface are some dead cells without nuclei and some dying cells with flattened nuclei

What's nonkeratinized?

cells on its surface all tend to have nuclei that appear fairly healthy and normal (alveolar mucosa)

What are the two units of the Periodontium?

gingival unit and attachment unit

What does the gingival unit contain?

1. free gingiva (gingival margin)

2. interdental papilla

3. attached gingiva

4. alveolar mucosa

What's the free gingiva?

extends from the gingival margin to the base of the gingival sulcus

What are the characteristics of the free gingiva?

light pink, forms a collar around tooth

What kind of tissue is free gingiva?

keratinized or parakeratinized

is the free gingiva attached to the tooth?

NO - fits close but not attached. Can be stretched away from the tooth surface with a probe

What's the interdental papilla(gingival papilla)?

located in the triangle interdental space

How many interdental papilla are there?

two; one lingual and one facial

Borders of the interdental pillar are formed by?

free gingiva

What the center part of interdental papilla formed by?

attached gingiva

What are the characteristics of interdental papilla?

when inflamed takes on more red than normal and appears puffy

What's the gingival sulcus?

space between the free gingiva and the tooth surface

What is the inner part of the gingival sulcus (tissue type)

nonkeratinized

What is the outer portion of the gingival sulcus made of (tissue type)

free gingiva so keratinized

What begins at the base of the sulcus?

attached

A gingival groove often occurs on the outside of the free gingiva corresponding to what?

base of the sulcus

What's the difference between a sulcus and pocket?

a sulcus is considered healthy but once inflamed it is called a pocket

What's junctional epithelium ?

attaches the sulcus to the tooth

Characteristics of the junctional epithelium

1-2mm long. forms a collar around the neck of tooth (base of sulcus)

What kind of tissue is the junctional epithelium and what does this do?

nonkeratinized stratified squamous epithelium

it makes it more permeable to fluids, bacteria etc

What's attached gingiva?

extends apically from the base of the sulcus and is attached to the bone by collagenous fibers

What does the attached gingiva look like?

stippled(orange peel), light to dark pink and may contain pigment

What kind of tissue is the attached gingiva?

keratinized

What kind of epithelium is the attached gingiva covered by?

stratified squamous

What's the alveolar mucosa?

joins the attached gingiva at the mucogingival junction and is continuous with the rest of the tissue to the vestibule

Characteristics of alveolar mucosa?

thin and soft, loosely attached to bone, composed of lining mucosa and nonkeratinized

The attachment unit is compromised of what three things?

cementum, alveolar bone and periodontal ligament

What's function of the attachment unit?

support, nutritive (vessels and nerves), formative (replace cementum, pdl and bone) and sensory

What's the job of the cementum in the attachement unit?

anchors the ends of the pdl fibers to the tooth. Without cementum tooth would fall out of socket

What does the outer layer of the cementum do?

protects the underlying dentin and seals the ends of the open tubules

Where is acellular cementum?

the cervical 1/3 portion of the root, sometimes extends over almost all of apical portion

Where is cellular cementum?

covers the apical portion and may form over aceullar

What influences the growth activity of cementum?

changes in function and pressure

What do both cellular and acellular cementum have?

collagen fibers embedded

What are sharpey's fibers?

embedded ends of connective tissue fibers of the periodontal membrane. Some embedded in bone some in cementum

What is the kind of bone that lines hte sockets in which the teeth are held?

alveolar bone proper

What is the alveolar bone proper?

thin and compact that lines the socket and provides blood vessels and nerves

What's the alveolus?

bony socket in which the tooth fits

What kind of bone is the alveolar bone?

compact or cotrical and spongey

What's the alveolar crest?

the portion of the alveolar bone located between teeth

Once teeth are extracted what happens to the alveolar bone?

resorbs

What's the periodontal ligament?

a fibrous connective tissue that surrounds and attaches the tooth roots to the alveolar bone

What connects the PDL to the cementum and bone?

sharpeys fibers

What prevents tooth mobility?

collagen fibers that insert into the cementum

What are the five groups of the periodontal ligaments fibers?

alveolar, horizontal, oblique, apical and interradicular

What's the alveolar crest group of pdl?

fibers extending from the cervical area of the tooth to the alveolar crest

What's the horizontal group?

fibers running horitzonally from the tooth to the bone

Whats the oblique group?

fibers running from cementum to bone

What's the apical group?

fibers radiating apically from the ttooth to bone

Whats the interradicular group?

periodontal fibers between multirooted teeth

What are the clinical considerations that exert pressure on teeth?

1. active eruption

2. mesial drift

3. occlusal forces

4. ortho corrective forces

5. traumatic occlusal forces