Dentin Flashcards
Characterized as positively birefringent?
Dentin
Color of dentin?
Yellow intrinsic color
Organic material of dentin? (3)
- Collagen
- Ground substance
- Water
Types of dentin. (4)
- Primary
- Secondary
- Tertiary
- Predentin/dentinoid
Also known as orthodentin or regular dentin?
Primary dentin
Other terms of tertiary dentin?
- Reactive
- Reparative
- Irregular secondary dentin
Primary dentin is developed before or after tooth eruption?
Before tooth eruption
It has regularly arranged dentinal tubules?
Primary dentin
Peripheral layer of dentin found adjacent to the enamel in the crown and cementum in the roots?
Mantle dentin
Layer of dentin containing collagen alpha fibrils?
Mantle dentin
True or false. Incremental lines can be found in mantle dentin?
False
Makes up the bulk of dentin?
Circumpulpal dentin
Dentin consisting of beta fibrils and mucopolysaccharide grounds substance?
Circumpulpal dentin
Acts as a lubricant or as shock absorber?
Mucopolysaccharide
True or false. Dentin is hydrophilic?
True
Intertubular dentin consist of what type of collagen fibers?
Type 1
Dentinal tubules exhibit ___? shaped curvature.
S shaped
Regularly arranged canals from pulp to DEJ/DCJ
Dentinal tubules
True or false. Dentinal tubules are more pronounced in the incisal and cuspal areas.
False
Why are dentinal tubules few in incisal/cuspal areas?
Due to crowding of odontoblasts as more dentin is formed
True or false. Tubules in root dentin has less S curvature?
True
Types of branching. (2)
- Dichotomous
- Greater branching
Contents of dentinal tubules. (3)
- Odontoblastic process
- Periodontal space
- Intratubular nerve
Other term for odontoblastic process?
Tome’s fiber or dentinal fiber
Cytoplasmic extension of odontoblasts?
Odontoblastic process
Found between the odontoblatic process and wall of the tubule?
Periodontoblastic space
Periodontoblastic space contains ____?
Dentinal fluid
Dentinal tubules filled with air?
Dead tracts
Causes of dead tracts? (2)
- Retraction of odontoblastic process
- Death of odontoblast
Occurs when dentinal tubules have become occluded with calcified material?
Sclerotic dentin
Glossy appearance of dentin is due to formation of?
Sclerotic dentin
Note: In sclerotic dentin, there is no odontoblastic process..
Filled with intratubular dentin instead
True or false. Sclerotic dentin decrease with age.
False. Increases
Part of tooth where sclerotic dentin is found?
- Apical 1/3 of root
- Midways between DEJ and pulp
Globular zones of dentin mineralization?
Calcospherites
Areas of hypomineralized dentin where calcospherites failed to fuse?
Interglobular dentin
Formation of interglobular dentin is due to? (2)
- Vitamin D deficiency
- Exposure to high levels of fluoride
True or false. Tubules in interglobular dentin are uninterrupted.
True
True or false. Interglobular dentin is found in circumpulpal dentin.
True
Black structures located in the root dentin adjacent to cementum?
Granular layer of Tome’s
True or false. Granular layers of tomes is seen decalcified section?
False. Seen only in ground section
Incremental lines of dentin?
Von Ebner
Dentin is mineralized in a __ hour cycle?
12
Changes in coloration of dentin?
Contour lines of Owen
It intercepts the DEJ and meet an accompanying Striae of Retzius?
Contour lines of Owen
Formative organ of dentin?
Dental papilla
Embryonic origin of dentin?
Ectomesenchyme
Formation of dentin begins at what stage of tooth development?
Late bell stage
First sign of dentin formation?
Appearance of Von Korff’s fibers
Fibrils of odontoblasts?
Beta fibrils
Composition of predentin? (2)
- Collagen fibers
- Ground substance
Theories of dentin sensitivity? (3)
- Direct conduction
- Transduction
- Hydrodynamic theory
An unusual feature of dentin-pulp complex?
Dentin sensitivity
Overwhelming sensation percipeived by dentin-pulp complex?
Pain
Stimuli of dentin sensitivity comes from? (3)
- Airwater spray
- Contact with a bur or probe
- Dehydration
Part of tooth where dentin is more sensitive?
- Along the DEJ
- Near the pulp
Theory states that dentin is directly innervated?
Direct conduction
Downside of direct conduction theory?
Not all tubules have nerves
Theory states that odontoblasts acts as receptors?
Transduction theory
Theory that states: Fluid movement stimulates receptors in the pulp
Hydrodynamic theory
Two treatments for hypersensitivity.
- Interrupt neural response to pain
- Occlude open tubules
Disturbance of dentin mineralization causes?
Dentinogenesis imperfecta
Dentinogenesis imperfecta is characterized by? (3)
- Abnormally translucent enamel
- Bulbous crown with short root
- Obliteration of the pulp
Placement of calcium hydroxide liner for deep cavities?
Indirect pulp capping
True or false. Sclerotic dentin is observed after endodontic therapy.
False.
No pulp or odontoblasts, therefore no sclerotic dentin formed
Houses the pulpal tissue?
Pulp cavity
Occupies the coronal pulp?
Pulp chamber
Occupies the radicular pulp?
Root canal
Openings of the pulp is called?
Orifices
Lateral branching of the main root canal?
Accessory canal
Allows communication between pulp and periodontal ligament?
Accessory canal
Serves as an avenues for spread of disease from one tissue to another?
Accessory canal
Where blood vessels and nerves enter and exit the tooth?
Apical foramen
Describe the apical foramen of newly erupted teeth.
Open and should not be extracted
True or false. As tooth completes its development, apical foramen becomes more centrally located.
False. More eccentric
What makes apical foramen more occlusally located than the anatomical apex? (2)
- Deposition of cementum
- Resorption of dentin
Narrowest portion of pulp cavity?
Apical constriction
Functions of pulp. (5)
- Inductive
- Formative
- Sensory
- Nutritive
- Defensive
Morphotic response of pulp?
- Formation of tertiary dentin
- Formation of sclerotic dentin
Inflammatory response of pulp?
Pulpitis
Structural components of pulp (4)
- Odontoblastic zone
- Cell free zone
- Cell rich zone
- Pulp proper/pulp core
Develops after root formation is completed?
Secondary dentin
Asymmetric reduction in size and shape of the pulp chamber?
Pulp recession
True or false. Secondary dentin is deposited slower than primary dentin?
True
Change in direction which marks the separation of primary and secondary dentin?
Schreger’s line
Formed in response to noxious stimuli?
Tertiary dentin
True or false. Tertiary dentin has more dentinal tubules?
False. Fewer dentinal tubules
True or false. Tertiary dentin is found only on areas needed.
True
Uncalcified dentin
Predentin
It lines the innermost portion of dentin
Predentin
Predentin is calcified within ___ hours?
24 hrs
Covers the walls of dentinal tubules?
Intratubular dentin
Another term for intratubular dentin?
Peritubular dentin
True or false. Peritubular dentin is more mineralized and dense than intertubular dentin.
True
True or false. Peritubular dentin is continuously formed.
True
Found between the dentinal tubules?
Intertubular dentin
It forms the main bulk of dentinal material?
Intertubular dentin