Dental Pulp Flashcards
(41 cards)
The pulp is often referred to as the dentine-pulp complex because the odontoblast processes extend at least —- into the dentinal tubules. Therefore drilling dentine can potentially —- the pulp.
1/3
damage
What does the dental pulp contain?
Cells Fibres Ground substance Blood vessels Nerves
What are the cells of the dental pulp?
Odontoblasts Stem cells Fibroblasts Schwann cells Defence cells (antigen presenting cells, macrophages, fibroblasts)
What are the four functions of the dental pulp?
- Forms the dentine
- Eruption of the tooth/root formation
- Dentine repair
- Defence against infection and systemic dissemination
Hard connective tissue of —–origin, formed by odontoblast cells of dental —-.
Dentine provide the bulk and form of tooth
Dentine forms —- enamel: it determines the —- of the crown, including cusps and ridges and the number and size of the roots.
Dentine is covered by enamel on the anatomic crown and —- on the anatomic root.
Internally, dentine forms the walls of the pulp of the pulp cavity (pulp chamber and pulp canal).
As a living tissue, dentine contains within its —- the process of specialised cells, the odontoblasts.
Mesodermal
papilla
before
shape
cementum
tubules
What are the physical properties of dentine?
light and colour
- Varies from light yellowish in deciduous teeth to pale yellow in permanent dentition
- Becoming darker with age
- Because light can readily pass through thin, highly mineralised enamel and be reflected by the underlying dentine, the crown of the tooth has a yellowish appearance
- Thicker enamel does nit permit light to pass through as readily, and in such teeth the crown appears whiter
- Teeth with pulp disease or without a dental pulp show discolouration of the dentine, which causes a darkening of the clinical crown
Explain the hardness of dentine:
- Less hard than enamel
- The hardness of dentine averages 1/5 of enamel and its hardness near the EDJ is about three times greater than near the pulp
- Dentine becomes harder with age, primarily due to increase its mineral content
- The lower content of mineral salts in dentine renders it more radiolucent than enamel
- Physically, dentine has an elastic quality, which is important for the proper functioning of the tooth because it provides flexibility and prevents fracture of the overlying more brittle non-resistant enamel.
What is the chemical composition of dentine?
What does each part contain?
70% organic, 20% organic, 10% water.
Hydroxyapatite and the organic phase is type 1 collagen with rational inclusions of glycoproteins, proteoglycans and phosphoproteins.
It contains a small amount of phosphates, carbonates and sulphates, insoluble protein and lipids.
What content increases with age?
Mineral content.
The inorganic phase makes dentine slightly harder than bone and softer than enamel.
How can organic and inorganic substances be separated?
What happens in the process of decalcification?
- decalcification
- incineration
Organic consistents can be retained and maintain the shape the dentine.
Why is dentine highly permeable?
Presence of dentinal tubules.
Is intratubular or intertubular more mineralised?
Intratubular
Structure of dentine:
Odontoblasts, project their —- processes inside the dentinal tubules, up to 1/3 of dentinal thickness.
Dentine tubules are found throughout —-.
Tubules from pulp towards the periphery and join enamel at —-.
Tubules join the cementum at the dentino-cementum junction at —-level.
The dentinal matrix of —- fibres is arranged in a random network.
As dentine —-, the hydroxyapatite crystals mask the individual collagen fibres.
Cytoplasmic
Dentine
EDJ
Root
Collagen
Calcifies
What are the two types of tubule?
Where is the S shaped curvature least pronunced?
Straight and S tubules
In the cervical third of the root and between the incised edges&cusps.
Where do tubules have the largest diameter?
Where are there more tubules? Crown or root?
Near the pulp
Crown
What are canaliculi?
What are enamel spindles?
Lateral branches off tubules in dentine.
Tubules which extend through the EDJ to the enamel.
What is intratubular dentine?
The dentine that immediately surrounds the dentinal tubules.
This dentin forms the walls of the tubules in all but the dentin near the pulp.
It is more highly mineralised (about 9%) than intertubular dentine.
What causes the size of tubular lumen?
Which type of dentine forms first?
Continuous deposition of peritubular dentine.
Intertubular forms before intratubular.
Give details on intertubular dentine
- Main body of dentine is compose of intertubular dentine
- It is located between the dental tubules more specifically, between the ones of intertubular dentine
- About one half of its volume is organic matrix, specifically collagen fibres which are randomly orientated around the dentinal tubules
- Hydroxyapatite crystals, which average 0.1um in length, are formed along the fibres with their long axis orientated parallel to collagen fibres
When does dentine become sensitive?
covering of either enamel or cementum is lost due to attrition, abrasion. erosion, caries, fracture, gingival recession
Sensitivity in dentine:
What happens with moderate stimuli?
What happens with severe stimuli?
- Pulp responds defensively forming tertiary dentine and sclerotic dentine
- It may damage the pulp (reversible or irreversible). Irreverisible leads to necrosis of pulp and periapical lesions.
Give the details on predentine
First formed dentine, not mineralised. Located adjacent to the pulp tissue and 2-6um wide depending on the activity of the odontoblast.
As the collagen fibres undergo mineralisation at the predentine-detnine from the predetnine then becomes dentine and a new layer or predentine forms circus pulpally.
It is the inner most portion of dentine.
What type of dividing cells are odontoblasts?
What is their shape in the crown and root?
Post-mitotic cells (cannot divide).
Tall and columnar in crown and cuboidal in root.
What are two specials things that an odontoblast cell has?
Cilia and Microtubules
