Periodontal Ligament Flashcards
what is the integral part of periodontal ligament?
gingiva
name 5 periodontal tissues.
tooth
cementum
gingiva
periodontal ligament
alveolar bone
what is the periodontal ligament and what does it contain?
cells
extracellular matrix
fibres
nerves
blood vessels
what does the periodontal ligament matrix contain?
hyaluronate glycosaminoglycans
proteoglycans
glycoproteins
what is the property of periodontal ligament matrix?
behaves as a viscous elastic gel
what does the complex structure of proteins in periodontal ligament matrix allow for?
them to be embedding in water
name cells found in the periodontal ligament?
FIBROBLASTS - found in abundance
CEMENTOBLASTS
OSTEOCLASTS - destroy bone
CEMENTOCLASTS - destroy cementum
EPITHELIAL CELLS - cell rests (debris) of malassez - desmosomes
DEFENCE CELLS
what do sensory nerves do in the periodontal ligament?
measure force applied (consistency of food vs jaw movement)
recognise danger (open mouth to protect teeth when scared)
SENSITIVE
what type of sensory nerves are present in the PDL?
mechanoreceptors
nociceptors
what is the function of autonomic (sympathetic) nerves present in the PDL?
blood vessel control
vasoconstriction
why can a denture/ implants not recognise the function of sensory neurons?
when tooth extracted periodontal ligament is lost
what is the true periodontal ligament?
fibres connecting tooth to bone at apical or alveolar crest
what is the gingival ligament?
fibres a=mainly above the alveolar crest including free gingival fibres
function of the PDL?
- attaches tooth to jaw
- transmits biting force to alveolar bone
what is the width of PDL?
0.2mm approx
what are the 5 fibre subgroups of the alveolo-dental ligament group?
alveolar crest horizontal
oblique
apical
inter-radicular (multi-rooted teeth)
where are trash-septal fibres of the interdental ligament found?
embedded into the cementum of the adjacent teeth where they form an interdental ligament
what do alveolo-dental ligament fibres do?
help the tooth to withstand the natural compression forces
in the alveolo-dental ligament what do oblique fibres do?
stretch and transfer forces
resist biting force
suspend tooth within socket
in the alveolo-dental ligament what do alveolar crest & horizontal fibres do?
help teeth move laterally and rotationally
what are trans-septal fibres?
goes through septal to connect 2 teeth
what happens in periodontal ligament moving?
apply brief force
measure tooth movement
how did tooth move?
what happens when force removed?
relative to tooth and bone, in which direction do periodontal fibre ligaments run?
from bone to insert more apically into the cementum
