periodontium I - cementum and PDL Flashcards
what is the only part of the periodontium that DOES NOT remodel
cementum
T/F all types of cementum contain type I collagen
true
what types of cementum have sharpeys fibers
AEFC and CMFC
what type of cementum DOES NOT have sharpeys fibers
CIFC
what type of cementum has a SLOW rate of deposition
AEFC
what types of cementum have a FAST rate of depostion
CIFC and CMFC
what cementum is found at the cervical 2/3 of root
AEFC
what cementum is found at mid-apical 1/3 root
CIFC
what cementum is found at apical 1/3 of root
CMFC
functions of cementum
-Tooth anchorage via PDL attachment
* Protection of the dentin-pulp complex;
* Adaptation (reshaping of root) due
to occlusal wear
* Repair from damage
what are extrinsic fibers of the PDL
sharpeys fibers
what represent deposition of cementum over time
Incremental lines of Salter (resting/cement lines)
if the Incremental lines of Salter (resting/cement lines) have close lines does that mean there was a slow or fast rate
SLOW
if the Incremental lines of Salter (resting/cement lines) have wide lines does that mean there was a slow or fast rate
FAST
what type of resorption can cementum undergo due to trauma
EXTERNAL root resorption
bc cementum is on EXTERNAL surface
can cementum show reversal lines?
yes!
T/F: cementum cannot repair
FALSE. CIFM and CMFC can!!!!
can cementum remodel
NO! no blood supply
reversal lines seen at exfoliation indicate REPAIR not true
remodeling
function of PDL
Supportive –serves as attachment site; withstands masticatory forces
Maintenance -high degree of turnover due mechanical stress
what types of sensory receptors can we find in the PDL
mechanoreceptors = ruffini
nociceptors = FNE
what do the mechanoreceptors in the PDL detect
detect pressure/stretch/proprioception:
o control bite force,
o provide feedback about duration,
o intensity and direction of applied force
what do the nociceptors in the PDL detect
pain and temp
do we find autonomics in the PDL
yes! sympathetics -> control BV
is the PDL well vascularized and supplies bone, cementum, gingiva
and if so, do the blood vessels form anastomoses between gingiva, bone, and PDL
yes yes
what cells are found in the PDL
Cementoblasts
fibroblasts
osteoblasts
osteoclasts
epithelial cell rests
macrophages/ WBC
undifferentiated STEM CELLS
what is the area called in the PDL that contains N, BV and lymphatic vessels
interstitial space
what are distinct fiber bundles that are recognized following eruption as tooth enters occlusion
principal fiber bundles of the PDL
2 groups of principal fiber bundles
Dento-alveolar fiber group – found between tooth and alveolus
Dento Gingival (supra-alveolar) group- found in lamina propria of gingiva
above alveolar crest
periodontal ligament appears as a radiolucent area of 0.15 to .24mm located between the ___________ and radiopaque lamina dura of the alveolar bone
radiopaque cementum
5 types of dento-alveolar fibers
alveolar crest
horizontal
oblique
apical
inter-radicular
fiber bundles that are found mid-root
horizontal
what is the function of horizontal fibers
resist tipping and horizonral movements
fiber bundles that are found apical 1/3
oblique
what is the most abundant fiber bundle
OBLLQUE!!!
fiber bundles that are found apex to fundic bone
apical
fiber bundles that are found b/w roots
inter-radicular
T/f
in dento-gingival fiber group, Fiber bundles DO attach to the alveolar socket (alveolar bone proper)
FALSE
Fiber bundles DO NOT attach to the alveolar socket (alveolar bone proper)
extend from gingiva to cortical bone or cementum
functions of dento-gingival fiber groups
hold (marginal/free) gingiva against the tooth:
* Protect against periodontal infection
* Reinforce the connection of junctional epithelium to tooth
* Provide rigidity to withstand masticatory force without distortion
* Reinforce the connection between the free and attached gingiva
* Link adjacent teeth and gingiva together
what are the 5 types of dento-gingival fiber groups
circular
alveolo-gingival
dentogingival
dentoperiosteal
transeptal
what fiber group encircles the tooth but DOES NOT ATTACH TO TOOTH
circular
what fiber group is from alveolar crest –> AG/FG
alveolo-gingival
what fiber group is from CEJ –> AG/FG
dentogingival
what fiber group is from CEJ –> cortical palte
dentoperiosteal
what fiber group is from CEJ –> another CEJ
transeptal
which fiber group prevents mesial distal separation
transeptal
what happens to our PDL space as we age
gets skinner and there is a decrease in turnover
hypofunction of PDL leads to
decrease in PDL space
for ortho, what all is happening on the TENSION SIDE
TENSION SIDE = bone formation via OB
increase in remodeling!
for ortho, what is all happening on the COMPRESSION SIDE (side tooth is tipping towards)
COMPRESSION SIDE = bone resorption via OC
