EX2; Periodontium - PDL and Alveolar Bone Flashcards
This is a soft connective tissue between the cementum and the bony wall of the tooth socket
PDL
What are the major components of the PDL
its large highly organized bundles of collagen fibers that have their ends embedded in the cementum and bone
What is the critical function of the PDL
attachment of the tooth to the bone
What is the thickness of the PDL
.2-.4; very thin and thins with age
What are the cells of the PDL
fibroblasts; most numerous cementoblasts osteoblasts osteoclasts Epithelial rests of Mallaez immune cells undifferentiated mesenchymal (stem) cells
These are large cells that secrete and degrade collagen, and are highly active (a measure of size)
fibroblasts
What type of cell-cell junctions do the fibroblasts contain
desmosomes
gap junctions; synchronize collagen secretion
cell-ECM junctions
This is one type of cell-ECM junction; fibronectin forms part of this junction
fibronexus
The cell-ECM junction is the functional link between what
occlusal forces and fibroblasts
allowing the fibroblast to react to those forces (including, secreting and degrading collagen, etc.)
The cell-ECM junction helps to maintain orientation of what
fibroblasts in PDL thus affecting orientation of collagen fiber bundles
The cell-ECM junction has links to what component
the actin skeleton and ultimately interacts with the collagen in the ECM
Where would you find the cementoblasts, osetoblasts, and osteoclasts in the PDL
near the tissue they are involved with
cementoblasts = cementum
osteoclast/blast = bone
What distinguished osteoclasts from the other adjacent cells
multiple nuclei
When would resorption of the cementum occur
in special situations like shedding of deciduous dentition or trauma
although small regions of cementum respiration is not unusual
These are remnants of HERS present in the PDL, lying closer to the cementum in clusters
Epithelial rests of Mallasez
What is the function of the Epithelial rests of Mallasez
unknown function; but an proliferate and form cysts
These cells lie close to the blood vessels and give rise to new cells, and contribute to maintaining the viability of the periodontium
undifferentiated mesenchymal cells (stem)
What are the fibers of the ECM of the PDL
collagen types I (80) and III (20) (also XII)
oxytalin
What are the ground substances of the ECM of the PDL; important in withstanding compressive loads
PGs and assocaited GAGs (water retention)
glycoproteins = fibronectin
Collagen forms what percentage of the PDL
47-52%
These are immature elastic fibers that tend to run at right angles to the collagen fiber bundles
oxytalin fibers
These are the ends of the collagen fibers that are inserted into mineralized tissue
Sharpey’s fibers
This is a spherical calcified mass in the PDL
cementicles
These are the collagen fibers of the PDL that are organized into bundles that function to attach cementum to the adjacent alveolar bone
principal fiber groups
What are the principal fiber groups
alveolar crest horizontal group oblique group apical group interradicular
This principal fiber group connects cementum to crest (top) of alveolar bone
alveolar crest
This principal fiber group connects cementum to alveolar bone below the crest
horizontal group
This principal fiber group is most numerous and connects cementum to alveolar bone; suspends tooth in socket
oblique group
This principal fiber group connects the apex of the tooth to alveolar bone socket
apical group
This principal fiber group is only in multi rooted teeth; between the cementum and interradicular septum of the alveolar bone
interradicular
This is important for maintaining the integrity of the PDL and supporting the tooth
gingival ligament
What are the groups of the gingival ligament
transeptal circular dentogingiva dentoperiosteal alveologingival
This group of the gingival ligament is from the cementum of the tooth over the alveolar crest into cementum on the adjacent tooth
transeptal
This group of the gingival ligament circles the neck of tooth in lamina propria of free and attached gingiva
circular
This group of the gingival ligament is most numerous, cervical cementum to lamina propria of free and attached gingiva
dentogingival
This group of the gingival ligament is from cementum over alveolar crest and inserts into the other side of alveolar bone
dentinoperiosteal
This group of the gingival ligament is from the alveolar crest to lamina propria of free and attached gingiva
alveologingival
What routes does the vascularization take to supply the PDL
enters the alveolar bone and then pierce foramina in wall of boney socket (perforating arteries)
branch near apical foramen and directly enter PDL
Which arteries does the blood supply to the PDL come from
superior and inferior alveolar arteries with contribution from gingival arteries
True or False
The nerve fibers that innervate the PDL get there by taking the same route that the blood vessels do
True
What fibers innervate the PDL
A delta
C
A beta
What do the sensory nerve fibers that supple the PDL signal
proprioception in addition to pain, carried by A beta fibers
What information does the PDL proprioceptors provide
the levels and direction of force applied to the teeth
This nerve fiber is intimately intermingled with collagen fiber bundles, is highly sensitive, codes for the AMOUNT and DIRECTION of force, sends info to the CNS to regulate chewing, and proprioception
A beta
In which direction(s) did the stimulus (from the cat experiment) respond the most
mesial force
distal direction = minimally
This is the bone of the jaw that contains sockets or alveoli for teeth
alveolar process
What is the apical dividing line between the alveolar process and the body of the maxilla or mandible apical to the root of the teeth
basal bone
What does the alveolar process include
outer cortical plate
central region of “spongy” or “trabecular” bone
the bone lining the socket
What are the three names of the bone lining the socket
bundle bone (contains PDL) cribiform plate (foramina) lamina dura (radiographic appearance)
From which tooth germ layer is the bone lining the socket derived from
dental follicle