connective tissue structure with its stratified squamous epith.

attaches the teeth to the maxilla and mandible.

provides a continually adapting structure for the support of the teeth during functions.

2 mineralized CT of Periodontium

Periodontium forms a specialized fibrous joint called

Periodontium DIVIDED INTO 2 based on function

consisting of free gingiva and alveolar mucosa

4 tissues of periodontium

cementum, periodontal ligament and alveolar process

the tooth root is attached to the alveolus (bony socket) by periodontal ligament.

-hard tissue with a calcified intercellular substance covering the anatomical roots of Teeth

this ligament is a complex, soft CT containing numerous cell, blood vessel, nerve fibers and ground substance.

-Thin of compact bone with many openings. -part of the maxilla and mandible - Supports the sockets

inner wall of bony socket. consists of thin lamella of bone that surround the root of the tooth and gives attachment to Sharpey's Fibers.

Which surrounds the alveolar bone proper and support the socket.

is a hard avascular connective tissue that covers the roots of teeth

thin layer of hard dental tissue covering the anatomic roots of teeth formed by cells known as cementoblasts, which develop from undifferentiated mesen-chymal cells in the connective tissue of the dental follicle.

light yellow and slightly lighter in color than dentin. avascular highest fluoride content of all mineralized tissues

formed continuously throughout life because as the superficial layer of cementum ages, a new layer of cementum is deposited to keep the attachment intact.

dull surface more permeable than other dental tissues softness and the thinness at the cervical portion

thickest in the apex and inter-radicular areas of multirooted teeth

cementum 10 to 15 um in the

cementum 50 to 200 um (can exceed > 600um)

organic matter + water percentage cementum collagen polysaccharides

inorganic or mineral content hyddroxyapatite crystals cementum percentage

cells in the cementum

Cells of cementum that are embedded in the calcified matrix within cementum doesnt have the capbility to form cementum

formative cells of cementum in the surface of cementum

cementocytes shrink and stay in

process of forming cementum happends during root development stage of tooth

2 steps in forming cementum

Embryonically, cells are derived from the dental sac or follicle (from ectomesenchyme)

UMC from PDL may Differentiate into

(Extension of the inner and outer dental Epithelium) forms and grows apically

sends inductive signal to ectomesen-chymal pulp cells to secrete predentin by differentiating into odontoblasts. Root dentin forms.

Hyaline layer of Hopewell-Smith also known as

not formed by cementoblast, but he rtwigs epithelial rooth sheath

cementoblast came from

uncalcified matrix of cementum lined by cementoblast is called

Connective tissue fibers from the PDL are embedded in the cementum and serve to attach tooth to surrounding bone (Bone bundle) arwe called

collagenous principal fibers of the periodontal ligament embedded in both cementum and alveolar bone to attach the tooth to alveolus.

Organic portion of cementum composed of

When thin layer of cementoid is formed, mineral salts from the tissue fluid of PDL is deposited as HA crystals along the collagen fibers.

Proteins - Ground substance - Water - Non-collagenous proteins Produced by cementoblasts or fibroblasts

incremental lines of salter are

cementum They are hypermineralized area with less collagen fibers and more ground substance

roles of cementum 4

living tissue that does not incorporate cells into its structure and usually predominates on the coronal half of the root

contains cementoblasts (inside the lacuna) and is often formed on the apical half.

(primary cementum)

(secondary cementum)

Represents cementum that is formed before the tooth is established in occlusiom

Represents all the cementum that is formed after the tooth comes in occlusion. • Continuously forms all through out life.

Cementum is more resistant to resorption: Important in permitting orthodontic tooth movement

3 classification of cementum

cementum Collagen fibers of Organic matrix is derived form 2 sources:

derived from PDL. same direction of the PDL principal fibers i.e. perpendicular or oblique to the root surface

derived from cementoblasts. Run parallel to the root surface and at right angles to the extrinsic fibers

The area where both extrinsic and intrinsic fibers is called

• First cementum • Primary cementum • Acellular • Before PDL forms • Cementoblasts • 15-20um

Located in cervical half of the root and constitutes the bulk of cementum

• Covers 2/3rds of root corresponding with the distribution of primary acellular cementum • Principal tissue of attachment • Function in anchoring of tooth • Fibers are well mineralized

cervical enamel • Forms the coronal cementum

extrinsic fibers coming from

Cementum that normally fills the resorption lacunae • Contains cementoblasts and collagen fbers produced by cementoblasts.

Cementum that is found at the apical third of the root, apices and furcation areas of multi-rooted teeth.

It contains cellular components and collagen fibers derived from cementoblasts and PDL

Cementum overlaps enamel

Cementum just meets enamel

Small gap between cementum and enamel

4 signs of aging cementum

Calcified ovoid or round nodule found in the PDL • Single or multiple near the cemental surface • Free in ligament; attached or embedded in cementum • Aging and at sites of trauma

occurs at or apical to the CEJ.

soft, progressive lesion that is found anywhere on the root surface that has lost its connective tissue attachment and is exposed to the environment.

Demineralisation is approximately twice as rapid on root surfaces as on enamel

most common reasons for root caries occurrence is

apical migration of marginal gingiva

FORMATION AND PROGRESSION OF DENTAL CARIES increased risk for root caries among individuals with 3 reasons

Soft, specialized connective tissue situated between cementum and the alveolar bone lining the socket.

bacterial organism that cause dental caries in ENAMEL

bacterial organism that cause dental caries in DENTIN

bacterial organism that cause dental caries in ROOT

It is a hard avascular connective tissue that covers the roots of teeth

5 FUNCTIONS OF PDL

resorptive cells of pdl

intercellular substances of pdl

one component of PDL you dont see in other structure

epithelial cells of pdl

2 kinds of PDL fibers

PDL help attached gingiva tp the tooth

attached to the cementum to the lamina propria

originate from the tip of alveolar bone to the lamina propria

fibers that goes around the tooth on the cervical region forms a band help bind gingiva to prevent from getting freeid out of tooth

originate from cementum pass beyond tip of alveolar bone to insert into periostium of alevolar bone

only type of fiber attached from one tooth to another tooth in the gingival region attached to two teeth

one end attached to the bone and one to cementum

From cementum goes downward Attached to the tip of alveolar bone neck region

Perpendicular or at right angle of the long axis of tooth

Main and most numerous alveolodental ligament Attachment on the bone is higher than to other tooth Mana support during mastication

Fan shape orientation of fibers at the tip of the root radiate on the apical region of root