DEN 105 Periodontium Supporting Structure

lecture #2

Periodontium

Tissues that support teeth

consists of two units: the gingival unit and attachment unit

Gingival unit

• free gingiva (mobile, not attached to the teeth)

• attached gingiva (tightly adhere to the bone)

• alveolar mucosa

attachment unit (attachment apparatus)

• cementum

• alveolar process

• periodontal ligament PDL

Gingival Tissue Properties

most important tissues of the orofacial region

even with restorative treatment, the impact on the gingival tissue must be considered

mucogingival junction

junction of the alveolar mucosa and the attached gingiva

mucosa

mucous membrane lining

• epithelium and connective tissue called lamina propia

epithelium

2 types: keratinized and non keratinized

keratinized

keratins (protiens) that make the epithelium stronger, maintains integrity of structure, impervious to water, more resistant to trauma, better protection againist abrasions

non keratinized

keratin is absent in the epithelial cells, pervious to water, only provides moderate protection against abrasions

masticatory mucosa

makes up both free and attcahed gingiva

• thick epithelial covering

• keratinized cells

• dense collagen fibers

• also on hard palate

alveolar mucosa

apical to the MGJ and is coninuous with the rest of the mucous membrane of the mouth

thin, freely movable, tears easily

free gingiva

marginal gingiva, light pink, located at the gingival margin of each tooth and is continuous with the attached gingiva

gum tissue that extends from the gingival margin

gingival sulcus

natural space between the free gingiva and the tooth

healthy gingival sulcus is 3 mm or less

gingival tissue anatomy

free gingiva width from 0.5 to 2.0 mm from the free gingival crest to the attached gingiva

the free gingiva follows the scalloped pattern established by the contour of the cementoenamel junction (CEJ) of the teeth also known as cervical line

forms a collar separated from the tooth by the gingival sulcus

cementum

layer of hard, bonelike tissue which covers dentin of anatomical root of a tooth

cervical line

identifiable line around external surface of a tooth where enamel and cementum meet and also called enamel junction or CEJ

separated anatomical crown and anatomical root and is a constant entity

interdental papilla

coronal to the marginal gingiva

triangular shaped extensions of the free gingiva that fills the proximal surfaces in between adjacent teeth

free gingiva located in the triangular interdental spaces

gingival papilla

Shape of interdental papilla

affcted by

• location of contact area of adjacent teeth

• shape of the interproximal surfaces of adjacent teeth

• cementoenamel junction CEJ of adjacent teeth

inner portion lined with nonkeratinized epithelium

outer portion covered with keratinized epithelium

periodontal disease

both the marginal gingiva and attached gingival can become enlarged, especially the interdental papillae.

 This spongy enlargement results from edema occurring in the lamina propria of the tissue caused by the inflammatory response

free gingiva

Free gingival groove—at margin of the free gingiva

Not always present; normal to be present

Corresponds to the base of the sulcus

Lamina propria

connective tissue fibers, keeps the gingiva firm

intermingle with the fibers of the attached gingiva and the periodontal ligament

circular fibers encircle teeth and tie them together- keep the free gingiva firm, do not embed in bone or cementum

col

concavity or depression of the interdental papilla that is found under the contact area

attached gingiva

not mobile

lamina propria is attached to bone underneath it

more keratinized and less fragile than free gingiva

extends from the base of the sulcus to the mucogingival junction

Color ranges from light to dark pink and may contain pigment correlating to the skin pigmentation of the person.

Often appears stippled, like the surface of an orange

stippling

caused by rete peg formation

rete peg formation

irregular binding of the epithelium to bone by collagen fibers; causes the stippling

Extension of the epithelial tissue into the underlying connective tissue causing it to tightly attach the attached gingiva to the bone

 Think of stippled as stapled or like nails in wood

sharpey’s fibers

in the lamina propria of the attached gingiva

embedded in the cementum or alveolar bone

Keep the gingiva closely attached to the tooth surface

 Can extend to the gingiva, tooth to bone, or tooth to tooth

gingival fibers group

circular group, cementum-free gingiva, cementum-attached gingiva, cementum-(over crest of bone) attached gingiva

circular group

only found in the free gingiva, not attached to the cementum or the bone

cementum-free gingiva

dentogingival fibers

cementum-attached gingiva

dentogingival fibers

cementum-(over crest of bone) attached gingiva

dentoperiosteal fibers

alveolar mucosa

• joins the attached gingiva at the mucogingival junction

• thin, soft, loosely attached to the underlying bone

• composed of the lining mucosa

• submucosa contains loose connective tissue, fat and muscle fibers

• vascular, more red than the gingiva because of shallow blood vessels and thinner epithelium

cementum

hard, bonelike tissue covering the roots of teeth

periodontal ligament

tissue that surrounds the roots of teeth and connects them to alveolar bone

alveolar bone

thin covering of compact bone that surrounds teeth

supportive

maintain support for teeth and prevent movement

formative

cementoblasts, fibroblasts, osteoblasts replace cementum, periodontal ligament and alveolar bone