Oral Biology Flashcards
Where is the pulp derived from?
Dental papilla
What is the apical delta?
Where exit/entry of vessels/nerves occurs through a number of small foraminae
What is the primary function of the pulp?
To produce dentine
What are the four zones of the pulp?
- Odontoblast layer
- Cell-free zone of Weil
- Cell-rich zone
- Pulp core
Which zone of the pulp is thought of as an artefact as not all people have it?
Cell-free done of Weil
What cells make up the cell rich zone of the pulp?
- fibroblasts
- pulpal stem cells
What is contained within the pulp core?
Blood vessels and nerves
What is the terminal web?
System of junctional complexes (e.g. desmosomes) that attach the cells tightly together
What is the function of fibroblasts?
Involved in the synthesis, turnover and breakdown of collagen and non-collagenous proteins
What are the four inflammatory cells present in the pulp?
- pulpal dendritic cells
- macrophages
- histiocytes
- lymphocytes
What receptors within the pulp result in vasoconstriction?
Alpha 1 receptors
What chemical does the nerves in the pulp release that causes vasodilation and therefore increases localised blood flow and vascular permeability?
Substance P
How does release of substance P result in sensitisation of the nerve endings?
Causes mast cells to release histamine, which sensitises the nerve endings
What fibres are mostly associated with the pulp, which are slowly conducting and give rise to slow, burning pain?
Non-myelinated C-fibres
What fibres in the pulp are myelinated and give rise to a more sharp/shooting pain?
A delta and A beta fibres
What zone of the pulp is the plexus of Raschkow found?
In the cell free zone
What stem cells can form bone or dentine and have a high proliferation rate?
Human exfoliated deciduous teeth (SHED cells)
What two main growth factors are present in dentine, and induce odontoblast differentiation and dentinogenesis?
- TGF-beta 1
- BMP
What are the two types of tertiary dentine?
Reactionary and reparative
What type of tertiary dentine does the pulp produce upon a mild (slowly progressing caries or tooth wear) stimulus?
Reactionary
What type of tertiary dentine does the pulp produce upon a strong caries stimulus?
Reparative
What structure is formed from pulpal stem cells during reparative tertiary dentine formation?
A dentine bridge
What structure delineates the border between the pulpal tissues and the periodontal tissues?
Cemento-dentinal junction
What are the Endo features of a maxillary central incisor?
- 3 pulp horns in pulp chamber
- single oval root canal
What is the average length of a maxillary central incisor?
22.5mm
What are the Endo features of a maxillary lateral incisor?
- no pulp horns
- single root canal
- wider chamber labio-palatally vs mesio-distally
- root apex palatally placed
What is the length of a maxillary lateral incisor?
22mm
What are the Endo features of a maxillary canine?
- no pulp horns
- single root canal
- chamber wider labio-palatally vs mesio-distal
- canal narrows in apical region
What is the average length of a maxillary canine?
26.5mm
What are the Endo features of a maxillary 1st premolar?
- 2 pulp horns
- typically 2 roots + 2 root canals
- thin often very curved apices
What is the average length of a maxillary 1st premolar?
20.6mm
What are the Endo features of a maxillary 2nd premolar?
- 2 pulp horns
- usually 1 root and 1 root canal (can be 2 root canals)
What is the average length of a maxillary 2nd premolar?
21.5mm
What are the Endo features of a maxillary 1st molar?
- 3 roots
- 4 canals: MB, MB2, D,P
What is the average length of a maxillary 1st molar?
20.8mm
What are the Endo features of a maxillary 2nd molar?
- 3 roots
- 3 canals: MB, D, P
What is the average length of a maxillary 2nd molar?
20mm
What are the Endo features of a mandibular central incisor?
- 2 pulp horns
- 1 root
- can be 2 or 1 root canal/s
What is the average length of a mandibular central incisor?
20.5mm
What are the Endo features of a mandibular lateral incisor?
- 2 pulp horns
- 1 root
- can have 1 or 2 root canals
What is the average length of a mandibular lateral incisor?
20.7mm
What are the Endo features of a mandibular canine?
- no pulp horns
- single root canal
What is the average length of a mandibular canine?
25.6mm
What are the Endo features of a mandibular 1st premolar?
- 2 pulp horns (buccal pulp horn higher than lingual)
- single root canal
What is the average length of a mandibular 1st premolar?
21.6mm
What are the Endo features of a mandibular 2nd premolar?
- 2 pulp horns
- single root canal
- occasionally sharp distal curve at apex
What is the average length of a mandibular 2nd premolar?
22.3mm
What are the Endo features of a mandibular 1st molar?
- large pulp chamber
- 2 roots
- usually 3 canals: MB,ML,D
- can have 4 canals: distal root can have two canals
What is the average length of a mandibular 1st molar?
21mm
What are the Endo features of a mandibular 2nd molar?
- large pulp chamber
- 2 roots
- 3 root canals: MB,ML,D
- can be 2 or 4 root canals
What is the average length of a mandibular 2nd molar?
19.8mm
What is the best way to ascertain if LA has worked prior to pulp treatment?
Cold testing of pulp
Why is it challenging to achieve LA in an inflamed pulp? Explain in three steps.
- Low pH in inflamed tissue, this means lots of H+ which drives the equilibrium to favour charged LA molecules.
- Only uncharged molecules can pass through lipid bilayer therefore cannot get balanced proportion of charged and uncharged molecules inside the nerve.
- So less charged molecules inside nerve to be able to reversible block sodium channels.
What type of LA molecules are able to bind to sodium channels and block them. Charged or uncharged molecules?
Charged molecules
How does low pH reduces effectiveness of LA?
Reduces amount of LA to penetrate the Axon membrane
Patients with what medical condition should avoid use of lignospan special containing adrenaline?
Patient with severe cardiac condition
What is the downside of mepivacaine as an LA?
It lacks a vasoconstrictor, so it doesn’t have a long duration
What is an advantage of mepivacaine as an LA?
It has no preservative or stabiliser, this is good for allergies and the preservative tends to be what people are allergic to
How much adrenaline is there in a 2% lidocaine cartridge?
1:80,0000 Adrenaline
How much adrenaline is there in a 4% articiane cartridge?
1:100,000 adrenaline
Why does articaine have low toxicity?
Rapidly metabolises
Will a lidocaine infiltration through thin, porous bone work?
Yes, should work.
Will a lidocaine infiltration through thicker bone, in zygomatic process work?
Can be difficult, could still work.
Will lidocaine infiltration through very dense outer cortical bone work?
No
Will articiane infiltration through very dense outer cortical bone work?
May work
What needle length should be used for intraligamentary LA technique?
Ultrashort 10mm needle
