Oral Biology Flashcards by Emily Wilson

What do the tissues surrounding the teeth do?

They maintain the tooth in socket.
They resist masticatory load.
They are a defensive barrier,

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What is the junctional epithelium?

The junctional epithelium is the physical barrier separating the body tissues from the oral environment.

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What are the two categories of periodontal disease?

Diseases of gingiva alone

- Diseases of all periodontal tissues.

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What does cementum cover?

Root dentine.

Collagen matrix
Lamellar arrangement

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Acellular (extrinsic) cementum?

no cells
has sharpeys fibres
first formed
adjacent to dentine
present on cervical 2/3 of root

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Cellular (intrinsic) cementum?

contains cementocytes
later formed
present in apical parts of roots and in furcation regions
no sharpeys fibres
NO ROLE IN TOOTH ATTACHMENT
intrinsic collagen fibres parallel to surface

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What type of cementum is most likely to have a success rate after periodontal treatment?

acellular extrinsic fibre cementum as it contains sharpeys fibres- have the potential to regenerate.

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What happens to the alveolar ridge when teeth are lost?

When teeth are lost, the alveolar process is resorbed, leaving a ‘residual ridge’.

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What type of canals penetrate alveolar bone?

Volkmanns canals.

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What does the periodontal ligament contain?

A connective tissue, containing:
Cells
Extracellular matrix
Fibres
Nerves
Blood vessels.

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What glycoproteins are in the periodontal ligament matrix?

Fibronectin.

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What proteoglycans are in the periodontal ligament matrix?

proteodermatan sulphate

- chondroitin/dermatan SO4 hybrid

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What does viscoelastic gel mean?

Generate infrastructure in matrix that is viscoelastic- glue/gel, like a jelly wobbling. Remove pressure springs back- return to original shape. PD can change the chemical arrangement of the matrix, viscoelastic capacity is lost. PD- losing tissue and viscoelastic.

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What cells are in the periodontal ligament?

Fibroblasts (generate and maintain infrastructure)
Cementoblasts 
Osteoclasts &amp; cementoclasts
Epithelial cells
Cell rests (or debris) of Malassez 
Defence cells.

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What are the sensory and autonomic nerves in the periodontal ligament?

Sensory:
Mechanoreceptors (A and Aδ fibres)
Rapidly or slowly adapting
Proprioception; chewing control
Nociceptors  (Aδ and C fibres)
Protective reflexes; 
inhibit jaw elevator motor neurons

Autonomic (sympathetic):
blood vessels control - vasoconstriction.

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What arteries supply the PDL?

Inferior and superior alveolar arteries pass into the periodontal ligament from the alveolar bone.
Lingual and palatine arteries supply the gingivae.

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What are the two different periodontal fibres?

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True periodontal ligament
fibres connecting tooth to bone at or apical to alveolar crest
‘Gingival’ ligament
fibres mainly above the alveolar crest, including ‘free gingival’ fibres.

What are the two different periodontal fibres?

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True periodontal ligament
fibres connecting tooth to bone at or apical to alveolar crest
‘Gingival’ ligament
fibres mainly above the alveolar crest, including ‘free gingival’ fibres. Support the free gingivae
Present in lamina propria in marginal gingiva:
Dento-gingival
Alveolo-gingival
Dento-periosteal (tooth to periosteum)
Circular

What is the approx width of the PDL?

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0.2mm.

What are the three different fibres in the periodontal ligament?

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Collagen (Types I and III)
Principal fibres - true periodontal ligament
Support tooth; load-bearing
Oxytalan fibres
Present in human PDL
Function is uncertain
Elastic fibres (absent in humans)- biggest study models for PD is animals.

Interdental col. Epithelium here is nonkeratinized- no oading forces of mastication.

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What is the effect of loading on the PDL?

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Initial elastic component
• Later, viscous ‘creep’
• ‘viscoelastic’ properties
• Tension in PDL fibres • Compression of ECF.

What cells are in the dental pulp?

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Odontoblasts, fibroblasts and defence cells.

What are the extracellular components of the dental pulp?

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Fibres: collagen, oxytalan
Matrix: proteoglycans, chondroitin SO4, dermatan SO4

What are the functions of the pulp?

``` Nutritive - blood vessels Dentine growth (primary, secondary) Dentine repair (tertiary) Defence Immune cells; lymphatics Neural Sensory - Pain? Control of dentinogenesis ```

What are the close links between pulp and dentine called?

Dentine-pulp complex.

Where do the pulp and dentine develop from?

Dental papilla.

What are the structural links between dentine and pulp?

``` Pulpal elements extend into dentine odontoblast processes nerve terminals immune cells (dendritic cells) dentinal fluid N.B. no BVs in normal dentine ```

Flow is proportional to what?

Pulp pressure.

What is the difference between reparative and reactionary dentine?

Reactionary dentine and reparative dentine are two strategies used by the dentine–pulp complex to respond to injury. The reactionary dentine is secreted by original odontoblasts, while the reparative dentine is formed by odontoblast-like cells (due to death of odontoblasts).

How does the odontoblast layer act as a permeability barrier?

Separates pulp and tubular space Regulates movement of material between pulp and tubular ECF Movement may be in either direction

What is the anatomy of the pulp nerves?

Branches of alveolar nerves Neurovascular bundles enter pulp via apical foramen and Pass along root canal in centre of pulp towards coronal pulp chamber Branches fan out in sub-odontoblastic layer ( Raschow’s plexus) Terminal branches enter odontoblast layer; some nerves enter dentinal tubules

What is the hydromechanics mechanicm of dentine pain?

1. Stimulus (mechanical, thermal, evaporative, chemical). 2. Exposed dentine/tubules. 3. Increase rate of dentine fluid flow. 5. AP generated and travel to brain to create PAIN.

Do nerves enter the dentine tubules?

Some do. Under the cusps 40% of tubules contain nerve. Nerve innervation in dentine is less in the coronal (15%) and root dentine (4%).

What are the four main factors that control pulp blood flow?

1. Circulating hormones 2. Nerves: sympathetic and somatic afferents. 3. Local factors eg. metabolites. 4. Drugs (LA with vasoconstrictor).

What are the functions of the pulp nerves?

1. Control of pulp blood vessels (sympathetic- vasoconstrictor, somatic afferents- vasodilator). 2. Sensory- mediating pain. 3. Promote neurogenic inflammation. Neuropeptides: Subst P, CGRP. 4. Promote dentine formation.

What are the steps of dentine-pulp responses to injury?

Immediate: nociceptors are activated and pain is established. After 1 minute there is an early inflammatory response and vasodilation occurs and prostaglandins and neuropeptides are released. After ten minutes there is an extraversion of fluid (oedema). Nociceptors are sensitised (there excitability is increased). After 100 minutes there are monocytes present and enemies are activated (nerve growth factor). After 1 day the nerves start to sprout and there is increased axon transport. There is altered excitablity of CNS synapses. After 1 week there is repair and tertiary dentine is formed.

What is pulpits?

Acute inflammation in the dental pulp. EXEPT THE PULP CANNOT SWELL. Oedema causes increased pulp pressure- variable effects on nerve excitability.

INTRA DENTAL NERVE PROPERTIES- what fibres they are and what they do.

A and A fibres (large & small myelinated): activated by hydro-dynamic stimuli applied to dentine probably mediate ‘normal’ dentinal sensitivity C- fibres (unmyelinated): probably activated directly by stimuli, rather than hydrodynamic mechanism they respond to most forms of intense stimulation probably mediate pain associated with pulp inflammation (e.g. caries)

Oral Biology Flashcards

(40 cards)