Periodontium Flashcards
what is the peridontium?
tissues supporting and surrounding the teeth
what are the functions of the peridontium?
- retain tooth in socket
- resist masticatory loads
- defensive barrier, protecting tissues against threats from oral environment
what is the physical barrier separating the body tissues from the oral environment?
the junctional epithelium
what are the different periodontal tissues?
- gingiva
- periodontal ligament
- alveolar bone
- cementum
- tooth itself
where is the cementum located?
covers the root dentine
what is the function of cementum?
provides attachment for some periodontal fibres
what are the two types of cementum known as?
- cellular cementum
2. acellular cementum
what cells lay down cementum?
cementocytes
what type of cementum is formed first?
acellular cementum
where is acellular cementum found?
usually adjacent to dentine
what cells are found in cellular cementum?
cementocytes
what type of cementum is formed later/second?
cellular cementum
where is cellular cementum found on the tooth?
- apical part of root
- furcation regions
what cementum has a role in a tooth attachment?
Acellular extrinsic fibre cementum
found in the alveolar bone, what does the cortical plate that forms the inner lining of the tooth socket provide?
provides attachment for periodontal ligament fibres (Sharpey’s fibres)
what occurs to the alveolar bone when the teeth are lost?
the alveolar bone is resorted
what type of tissue is the periodontal ligament? what does it contain?
a connective tissue containing =
- cells
- ECM
- fibres
- nerves
- blood vessels
what are the functions of the periodontal ligament?
- attaches tooth to jaw
- transmits biting forces to alveolar bone
what cells are found within the PDL?
- fibroblasts
- cementoblasts
- osteoclasts & cementoclasts
- epithelial cells
- defence cells
what is found within the extracellular matrix?
- hyaluronate GAGs
- glycoproteins
- proteoglycans
what is the function of the ECM?
acts as a viscoelastic gel
what types of nerves are located within the PDL?
sensory and autonomic nerves
what sensory nerves are found within the PDL?
> mechanoreceptors (Abeta and Adelta fibres)
> nociceptors (Adelta and C fibres)
what is the function of nociceptors within the PDL?
- protective reflexes
- can inhibit jaw elevator motor neurons
what autonomic nerve function does the PDL have?
blood vessel control
what is the blood supply of the PDL?
- from inferior and superior alveolar arteries passing into PDL from alveolar bone
- from lingual and palatine arteries supplying gingivae
what is the ‘gingival’ ligament ?
fibres mainly above the alveolar crest (including free gingival fibres)
what types of fibres are found in the PDL?
- collagen (types I and III)
- oxytalan fibres
what is the function of collagen fibres within the human PDL?
support tooth & load bearing
when might the PDL be subjected to intrusive forces?
- mastication
- swallowing
- speech
- parafunction (clenching/grinding)
