Term
What is dentin, and where is it located on the mature tooth? |
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Definition
| 70 % inorganic 20% organic 10% water. under the enamel and cementum. covering the pulp. |
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Term
What is the chemical formula of its most common mineral? |
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Definition
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Term
What other minerals are present in dentin? |
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Definition
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Term
Discuss the coloration of dentin in relationship to enamel and cementum, as well as its radiographic appearance. |
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Definition
| dentin is a more yellow color. and appears more radiolucent. |
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Term
Discuss attrition, gingival recession, caries, and dentin hypersensitivity as it involves dentin. |
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Definition
1. Attrition can occur quicker in dentin because of less mineralization
2. gingival recession will expose root dentin. dentin that is lost externally will not be replaced by secondary dentin
3. caries can effect dentin through bact.
4. bleaching causes dentin hypersensitivity |
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Term
Discuss staining of dentin and the procedures involving stain removal. |
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Definition
| dentin is stained because it has tubules and they suck in the stain making teeth yellow brow black. the hand tools may be to rough for the dentin so the suggestion is to use the ultrasonic |
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Term
What is dentionogenesis, and what stage of tooth development does it involve? |
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Definition
| process of dentin matrix or predentin formation that occurs during the apposition stage |
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Term
What happens during the apposition of dentin matrix? |
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Definition
| predentin laid down by odontoblasts, which is induced by ameloblasts to produce predentin in layers. forms about 4 micrometers a day. Occurs throughout tooths life. |
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Term
What happens during the maturation of dentin? |
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Definition
It mineralizes in 2 stages. calcium forms as globules. They fuse together.
later new globules are formed and partially mineralized while predentin fills in making it continuous. referred to as globular dentin |
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Term
What is the difference between globular and interglobular dentin? |
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Definition
| globular dentin has had phase 2 mineralization and interglobular has only had primary mineralization which did not fuse completely. |
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Term
Name and describe the appearance of the componts of mature dentin. |
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Definition
| dentinal tubules, dentinal fluid, avascular nutrition comes through tubule. |
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Term
Discuss the direction of the dentinal tubules in mature dentin. |
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Definition
| reflects the pathway of odontoblast. Primary and secondary curves. Primary is a large S shaped curve. Secondary is small curves within the primary noted as daily changes. |
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Term
List and explain the types of dentin in a mature tooth.
peritubular dentin
intertubular dentin
mantle dentin
circumpulpal dentin |
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Definition
1. dentin in the wall of dentinal tubule. Highly calcified
2. between the tubules. highly calcified
3. outermost layer. first dentin formed.
4. layer around the outer pulpal wall. layer formed after mantle. |
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Term
Describe the microscopic features of mature dentin. |
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Definition
1. imbrication lines of von ebner - growth rings stain darkly run at right angles to dentin tubules
2. contour lines of owen - adjoining parallel imbrication lines from disturbance in metabolism
3. neonatal line - trauma from birth.
4. tetracycline staining - antibiotic
5. tomes granular layer - unknown - granular appearance ( maybe less calcified) |
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Term
What happens to dentin as it ages? |
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Definition
| the diameter of the dentinal tubules narrows because of deposition of pretubular dentin. |
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Term
What is the pulp, and where is it located? |
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Definition
| innermost tissue of the tooth located in the center. the pulp is the heart of the tooth. |
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Term
How does the pulp appear on radiographs? |
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Definition
| less dense or more radiopaque then dentin. |
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Term
What are the functions of the pulp? |
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Definition
1. support maintenance and continued formation of the dentin. (inner cell bodies of odontoblasts along pulpal wall)
2. sensory dentinal tubules are among odontoblast layer
3. nutrition because it supplies dentin with nitrition.
4. protective because it is inolved in secondary or tertiary dentin. |
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Term
What is the developmental background of the pulp? |
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Definition
| derived from the dental papilla of the tooth germ. during odontogenisis when dentin forms around papilla the inner tissue is considered pulp |
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Term
Outline the anatomy of the pulp. |
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Definition
| mass of pulp is in pulp chamber. coronal pulp is near the crown of the tooth and coming of this is pulp horns. the radicular pulp is the pulp canals. Apical foramen is a hole at the bottom of the root that allows blood supply amoung other things in. Accessory canals are extra openings from pulp to periodontal ligament. |
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Term
Discuss pulpitis and its resulting complications. |
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Definition
| inflamation of the pulp. extreme pain that will lead to periapical cyst |
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Term
Describe the microscopic features of the pulp. |
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Definition
fibroblasts (largest group) odontoblasts (2nd largest) UMC, collagen and reticular fibers present in pulp. myelinated axons for sensory unmyelinated associated with blood vessels.
pulp stones - calcified masses of dentin in pulp |
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Term
List and explain the four zones noted when viewing pulp microscopically. |
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Definition
odontoblastic layer - lines the outer pulpal wall capable of producing secondary or tertiary dentin. most cells.
cell - free zone - contains a nerve and capillary plexus.
cell rich zone - has many cells and extensive vascularity.
pulpal core - vascularity consists of many cells similar to cell rich zone. |
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Term
What happen when pulp ages? |
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Definition
| decreased intercellular substance pulp becomes less regenerative and cavity begins to narrow due to constant addition of 2ndary and tertiary dentin. |
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Term
Discuss growth factors as they relate to dentin and pulp. |
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Definition
| play a pivatol role in tissue formation and repair of dentin pulp complex |
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Term
List and explain the types of dentin in a mature tooth.
Primary dentin
secondary dentin
tertiary dentin |
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Definition
1. formed before the completion of the apical foramen - formed more rapidly and is more mineralized then 2ndary.
2. formed after completion of apical foramen. formed slower and is less mineralized and continues to form throughout life of the tooth.
3. formed as a result of injury - irregular patterns of tubules |
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