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    DENTIN .....ORAL HISTOLOGY MCQ& Complete

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    DENTIN .....ORAL HISTOLOGY MCQ& Complete

    Post  Admin on Mon Apr 12, 2010 7:02 pm

    1
    -Interglobular spaces:

    a- Do not contain dentinal tubules.

    b- Do not contain type I collagen.

    c- Are formed during the course of globular mineralization.

    d- Are seen only in secondary dentin.



    2- Which would not be present in a ground section?

    a- Inorganic crystals.

    b-Odontoblast.

    c- Interglobular space.

    d- Dentinal tubules.



    3- A major difference between secondary and primary dentine is that:

    a- There is no predentine.

    b- There is no hydroxyapatite.

    c- There is no collagen fibers.

    d- The dentinal tubules pass in wavier course through secondary dentine.



    4- The interglobular dentin is found:.

    a- Near the amelo-cemental junction.

    b- In the root dentin.

    c- Near the amelo-dentinal junction.

    d- Near the dentino-cemental junction.



    5- Which of the following is MOST likely to be found in the dentinal tubules:

    a- Tomes' fibers.

    b- Oxytalan fibers.

    c- Tomes' process.

    d- Thick collagen fibers.



    6- Primary dentin differs from both secondary and reparative dentin in that:

    a- Its matrix is calcified.

    b- Its inorganic component is hydroxyapatite.

    c- It usually has a greater number of tubules per unit area.

    d- It is produced by mesenchymal cells.



    7- Which of the following is not present within dentin?

    a- Cell bodies.

    b- Hydroxyapatite.

    c- Collagen type I.

    d- Incremental lines.







    8- Which of the following is true of peritubular dentin ?It :

    a- Is less mineralized than intertubular dentin.

    b- May be considered as intratubular dentin.

    c- Is best visualized in decalcified sections.

    d- Is found in the interglobular dentin.



    9- Which of the following is not present in odontoblasts?

    a- Golgi saccules and vesicles.

    b- Rough endoplasmic reticulum.

    c- Desmosome-like junctions.

    d- Numerous processes forming a striated border.



    10- Human primary dentin contains:

    a- Mantle & circumpulpal dentin.

    b- Tomes' process.

    c- Cell bodies.

    d- Atubular dentin.



    11- Which of the following is considered as age changes?

    a- Transparent dentin.

    b- Cellular cementum.

    c- Primary dentin.

    d- Enamel spindle.



    12- Which of the following is true:

    a- A layer of predentin is found between primary and secondary dentin.

    b- Dentinal tubules do not pass through interglobular dentin.

    c- The physiological secondary dentin contain dentinal tubules.

    d- Many large collagenous fiber bundles are found in the dentinal tubules.



    13- Reparative dentin:

    a- Contain regular and numerous dentinal tubules.

    b- Obliterates the apical foramen.

    c- Forms on localized regions of the pulpal surface of the dentin.

    d- Formation is induced by the cells of the inner dental epithelium.



    14- Matrix vesicles are present during:

    a- The initial mineralization of dentin.

    b- The initial mineralization of enamel.

    c- The initial mineralization of cementicles.

    d- The initial mineralization of denticles.







    15- Which of the following is least prominent in odontoblasts and secretory ameloblasts?

    a- Rough endoplasmic reticulum.

    b- Mitochondria.

    c- Golgi apparatus.

    d- Lysosomes.



    16- Collagenous fibers are not found in:

    a- Mantle dentin.

    b- Reparative dentin.

    c- The outer prismless layer.

    d- The dental sac.



    17- Obliteration of the dentinal tubules by mineral deposits:

    a- Occurs only when the dentin becomes exposed to the oral fluids.

    b- Produces dead tracts.

    c- First occurs in predentin.

    d- Is seen in sclerotic and transparent dentine.



    18- Tome's granular layer is:

    a- An extension of odontoblast processes into enamel.

    b- A region lacking dentinal tubules.

    c- Following the incremental lines.

    d- Derived from the epithelial rests of Malassez.



    19- Amelogenesis and dentinogenesis are similar in which respect?

    a- Both processes involve the secretion of collagenous fibers

    impregnation with hydroxy-apatite crystals.

    b- Both processes involve maturation with hydroxyappatite crystals.

    c- Both processes start simultaneously at the early crown stage.

    d- Both processes continue throughout the life of the tooth.



    20- Which of the following is wrong?

    a- The formation of primary dentin continues throughout life.

    b- Primary dentin contains a significantly higher number of tubules per unit

    volume.

    c- Reparative dentin forms as a response to injury.

    d- Dead tracts are more common in secondary than in primary dentin.



    21- Which of the following has the highest mineral content?

    a- Predentin.

    b- Peritubular dentin.

    c- Intertubular dentin.

    d- Cementum.





    22-Dentin is a variety of Connective tissue because it:

    a- is elastic and contains mucopolysaccharides.

    b- contains collagen fibers and cell processes derived from mesenchyme.

    c- contains inorganic cells.

    d- has few cells and much intercellular material.



    23-Cementum is a tissue that:

    a- provides attachment of periodontal ligament fibers.

    b- is easily resorbed than bone.

    c- it contains blood vessels.

    d- it contains neural receptors.



    24-Cementum deposition cervically on enamel surface is due to:

    a- premature degeneration of epithelial root sheath of Hertwig.

    b- loss of reduced enamel epithelium.

    c- persistence of epithelial root sheath of Hertwig.

    d- cementoblasts coming from dental sac.



    25-Neonal line is present in:

    a- enamel and cementum. b- dentin and cementum.

    c- enamel and dentin. d- non of the above.



    26-Obliteration of dentinal tubules by minerals will result in:

    a- formation of dead tracts.

    b- formation of secondary dentin.

    c- formation of sclerosed dentin.

    d- formation of irregular or reparative dentin.



    27-Age changes will increase:

    a- dentin sclerosis. b- interglobular dentin.

    c- in cementum thickness. d- Tome's granular layer.



    28-formation of matrix vesicles in calcification of dentin is limited to:

    a- circumpulpal dentin. b- Mantle dentin.

    c- all types of dentin. d- non of the above.






    Dentin-Complete:


    1- .................. is the mineralized tissue that forms the bulk of the tooth.
    2-Two major properties distinguish dentin from enamel: First, dentin is .......... Second, dentin ...................................
    3- Dentin is slightly harder than...............or ............... and is less hard than ...................
    4- On radiographs, dentin appears more .................. than enamel and more ..................... (lighter) than pulp.
    6- The collagen of dentin comprises over 90% of the organic matrix. The principle collagen fibril is type ..................., traces of type III and type V collagen are also found.
    7-........................... are highly specialized connective tissue cells that differentiate from the peripheral cellular layer of the dental papilla.
    8- Secretory odontoblasts exhibit ...................... and ..................... activity along their plasma membranes.
    9- The................. odontoblast produces dentin in a very slow rate.
    10- In resting odontoblasts, there are increase in number and size of ............... and ........................
    11- The Mantle dentin varying in width from ................ µm. The large collagen fibrils (0.1-0.2 mm in diameter) aggregate in the cell free zone.
    12- The collagen fibrils of mantle dentin are aligned ...................... to the basal lamina, while in the mantle dentin of the root they are......................
    13- ..................................theory proposes that fluid movement through the tubules distorts the local pulpal environment and is sensed by the free nerve endings in the plexus of Raschkow.
    14- The ...................dentin is the basic structure of dentin and forms its bulk.
    15- The collagen fibers of ......................... dentin are smaller in diameter (0.05Mm) and are more closely packed and interwoven with each other.
    16- The fibers of circumpulpal dentin are present ............................. to the tubules.
    17- The ground substances of the ....................... dentin are exclusively a product of odontoblasts.
    18- The vesicles that bud from the odontoblast cells during mineralization of dentin are called ..............................
    19- .............................theory supposes that dentin contains nerve endings, which respond when dentin is stimulated.
    20- The function of .......................... is to provide a special micro-environment in which the first hydroxyappatite crystals can form.
    21- the presence of matrix vesicles is limited to........................ dentin.
    22- ....................... calcification founds in mantle dentin.
    23-................................. calcification usually presents in circumpulpal dentin formed just below mantle dentin.
    24- In the rest of the circumpulpal dentin, a combined pattern of calcification occurs with a ........................phase alternating with a .................... phase.
    25- The convexity of the primary curvatures of dentinal tubules nearest the pulp chamber faces..........................
    26- The ............................. result from the spiral track taken by the odontoblast during its course from the outer dentin surface to the pulp.
    27- In some places of the crown, the peripheral ends of some odontoblastic processes cross the dentino-enamel junction and protrude into the enamel, forming ...............................
    28- Dentin located between the dentinal tubules is called ......................................
    29- ...................................dentin is type of highly calcified dentin matrix deposited on the internal surface of the walls of the dentinal tubules narrowing the size of the lumen.
    30- .......................... dentin contains little amount of collagen. It is about 40% more mineralized than intertubular dentin.
    31- External stimulus accelerates ..........................r dentin formation that eventually may obliterate the tubules spaces.
    32- ......................... dentin will be seen as translucent rings in ground sections.
    33-....................................... is the area of unmineralized or hypomineralized dentin where globular zones of mineralization have failed to fuse within mature dentin.
    34- Inter-globular dentin is seen most frequently in the ........................ dentin just below the.................... dentin.
    35- ................................. is a constant feature of the root dentin immediately adjacent to cementum.

    36- .....................................do not follow any incremental pattern and usually smaller than interglobular dentin.
    37-...............................do not cross through Tomes' granular layer.
    38- Incremental lines of Von-Ebner run at right angles to..................................
    39- ........................................... may results from a coincidence of the secondary curvatures between neighboring dentinal tubules.
    40- ............................. could be seen in all deciduous teeth as well as in the mesio lingual cusp of the first permanent molar.
    41- .................................... dentin develops by odontoblasts after root formation has been completed.
    42- The reparative dentin with no tubules at all named ............................While that with trapped forming cells named .................................
    43- ............................. is characterized by calcification of dentinal tubules, where the odontoblastic processes undergo fatty degeneration and then calcification.
    44- ......................... dentin appears translucent when viewed by transmitted light while with reflected light these areas appear dark.
    45- Dentin areas characterized by degenerated odontoblastic processes have been called ......................................
    46- Each ...................... is surrounded and isolated by a narrow zone of sclerotic dentin.
    47- ..........................may be caused in some teeth by the death of odontoblasts crowded in narrow pulpal horns.
    48- ..................................... theory contends that a dental stimulus excites the odontoblastic process which then transmits the excitation to the adjacent nerve plexus

      Current date/time is Fri Dec 09, 2016 5:48 am