lecture 2- perio anatomy 2 (junctional epithelium) Flashcards
after tooth eruption, cells of the oral epithelium possess the ability to differentiate into what?
Junctional epithelium
JE (junctional epithelium) is widest in the _____ portion, and thin toward what tooth structure?
widest in the coronal portion
thins towards the CEJ
T/F: the junctional epithelium is continuously renewed
true
which cell type has a faster turnover rate: the oral epithelium or the junctional epithelium
junctional epithelium
what are the dimensions of the JE? from what structure does it originate?
only about 1mm long (ranges from .5-1.5)
reduced enamel epithelium (in pre-erupted teeth) gives rise to the JE
when comparing the JE to the OE, which has larger cells? which has larger intercellular spaces? which has more desmosomes?
Junctional epithelium- larger cells, larger intercellular space
Oral epithelium- more desmosomes
T/F: JE has the potential to keratinize
true
is the JE physically attached to the tooth, or just in contact with it?
physically attached
the JE will move _______ in diseased epithelium
apically
T/F: the JE if found just apical to the CEJ in children
False- found slightly coronal to the CEJ
moves to the level of the CEJ in healthy adults
when does periodontitis occur?
when the Junctional epithelium migrates apically down the root surface
what is necessary for pocket formation during periodontitis?
viable junctional epithelium
Necrosis of junctional epithelium is seen during what condition?
Necrotizing ulcerative periodontitis (NUP)
T/F: as cells die during JE necrosis, a large pocket is formed
FALSE
remember- you need viable (living) JE to have pocket formation
no pocket is formed during NUP
what is exposed during NUP (necrotizing ulcerative periodontitis)
bone is exposed
what cells are found in the lamina propria layer of the gingival CT?
- fibroblasts
- mast cells (M)
- macrophages
- neutrophilic granulocytes
- lymphocytes
- plasma cells
what types of fibers are found in the lamina propria of the gingival CT?
- Collagen
- reticulin
- oxytalan
- elastic fibers
what is the role of reticulin in the lamina propria?
surrounds blood vessels
keeps them upright
what is the function of elastic fibers in the lamina propria?
keep the blood vessels of the CT open
what cell types can produce collagen?
fibroblasts
cementoblasts
osteoblasts
what is the role of gingival fibers?
- reinforce the gingiva
- provide resilience and tone
- maintain architectural form and integrity
what is the role of circular fibers in the gingiva?
encircle the tooth like a cuff
_________ fibers fan out from supra-crestal cementum into free gingiva
dentogingival fibers
where do dentoperiosteal fibers run?
run from supracrestal cementum into attached gingiva
________ fibers run from tooth to tooth (embedded in cementum)
transseptal fibers
what are the characteristics of the periodontal ligament?
- richly vascular and cellular connective tissue
- surrounds the roots and joining cementum and alveolar bone
where is the periodontal ligament seen in radiographs?
the space between the lamina dura (alveolar bone proper) and root surface
(hourglass shape)
what is the function of the periodontal lig?
- permits occlusal forces to be distributed
- essential for the tooth mobility
what are the 4 fibers of the PDL?
Alveolar crest fibers (ACF)
horizontal fibers (HF)
oblique fibers (OF)
apical fibers (APF)
what type of cell is found aligned along the principal fibers of the PDL?
fibroblasts
where are osteoblasts found?
lining bone surfaces
_________ line cemental surfaces
cementoblasts
_________ are multinucleated cells that create ruffled surfaces of bone
osteoclasts
_________ are the remnants of the Hertwig’s epithelial root sheath
epithelial rest cells of Mallassez
Cementum is similar to bone, but has what key differences?
- no blood vessels
- no lymph vessels
- no innervation
- no physiological resorption/remodeling
T/F: cementum is continually deposited throughout life
true
what is the structural composition of cementum?
collagen fibers embedded in an organic matrix
what are the 3 classes of cemental fibers?
- intrinsic
- extrinsic
- “different forms”
what produces intrinsic fibers of the cementum? how are these fibers oriented?
produced by cementoblasts
composed of fibers oriented parallel to the root
what are extrinsic cemental fibers also known as? what are they produced by?
- AKA “Sharpey’s fibers”
- produced by PDL fibroblasts
where is acellular cementum found? cellular cementum?
acellular cementum- coronal
cellular- apical
osteoblasts of alveolar bone produce a bone matrix (osteoid) consisting of what?
- collagen fibers
- glycoproteins
- proteoglycans
In Alveolar bone, _______ undergo mineralization by the deposition of minerals
osteoids
which dental tissue most closely resembles bone?
cementum
