Periodontium- anatomy and function Flashcards
what is the periodontium?
supportive tissues and structures within the jaws- surrounding the teeth
what nerve innervates the periodontium? and what innervation does it provide?
CNV- sensory and autonomic innervation
what is the periodontium made up of?
- gingivae
- bone
- PDL
- cementum
what are PDL fibres called?
sharpeys fibres- principal fibres
what are the two parts of bone called?
- dense cortical bone- outer surface
- trabecular bone- spongey
what is the outer surface cortical bone called?
cribriform plate
what is the purpose of the alveolar bone?
supports the tooth by absorbing and distributing forces from mastication
can bone respond?
yes- by remodelling by osteoclasts and osteoblasts
what are bitewings used for?
- caries below the contact points
- bone loss if not significant
what is the white lamina dura on a radiograph?
cribriform plate (cortical bone)
why do you get radiolucent areas?
- when x-rays hit the film without being absorbed by hard tissues
- energy has penetrated through to film and will become exposed turning it black
why do you get radiopaque areas?
hard tissues absorb the x-ray energy and not hit the film
what are the types of gingival tissue?
- attached gingivae
- free gingivae
- alveolar mucosa
what are the phenotypes of each gingivae ?
- less kertataeised
- highly keratinsed (more resistant to trauma and inflammation)
what is free gingivae?
- not attached to tooth
- sits coronal to the attached gingivae
what is the attached gingivae ?
- protective cuff around the tooth and tightly bound to the underlying alveolar bone
- protects from food debris and bacterial invasion of the PDL and bone
where does the attached gingivae attach to the teeth?
at the ACJ
what is these parts
what is the purpose of junctional epithelium?
begins attachment to the tooth surface
what is the junctional epithelium made of?
- 1mm thick layer of epithelium
- known as hemi-desmosomes
if the gingival sulcus (biological width) is not respected with regards to restorations, what can happen?
- chronic inflammation
what is the gingival papillae continuous with?
the attached gingivae
are the gingival papillae keratinised?
yes but less- very fragile
the papilla are very innervated, what does that mean?
- they become inflamed and bleed due to vasodilation of blood vessels to allow more blood and inflammatory cells to the site of injury.
name each part
what is the PDL product?
dense fibrous connective tissue
what are sharpeys fibres composed of?
types I,II and V collagen
what is the role of the PDL?
- allow for normal physiological movement
- shock absorber
- sensory feedback
- connect cementum to bone- supports the tooth
- maintain and repair cementum and bone due to presence of stem cells.
is the pdl innervated?
yes- richly innervated. Inflammation would be painful and a patient would be able to localise the tooth in pain.
what are the types of gingival fibres?
what are the types of PDL fibres?
what do we want to happen to the pdl fibres after periodontal therapy?
tighten fibres
where is cementum found?
covering dentine at the root of the tooth (calcified)
cementum can’t remodel what does this mean?
it is more resistant to resorption
what happens to cementum during RSD?
diseased necrotic cementum is removed to make the surface biologically compatible with healing
what is the role of the cementum?
- pdl attachment to tooth
- protect underlying dentine
how is cementum linked to ageing?
apical cementum thickens with ageing- in response to normal tooth wear with ageing
