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Dentistry Tooth Development And Eruption

Subjects : health-sciences, dentistry

Instructions:

Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
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This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. What are the cell layers found in the enamel organ in the bell stage?
The outer enamel epithelium - the inner enamel epithelium - the stellate reticulum - and the stratum intermedium
The primary tooth can now erupt into the oral cavity - the REE fuses with the oral epithelium - then enzymes from the REE disintegrate the central portion of the epithelial tissue leaving an epithelial tunnel for the tooth to erupt
It disintegrates as the developing oral mucosa comes to line the oral cavity
Dental papilla

2. What is the function of the Hertwig's epithelial root sheath?
A mineralized cylinder - the dentinal tubule
Dental tissues fully mineralize to their mature levels.
To shape the root (or roots) and induce dentin formation in the root area so that it is continuous with coronal dentin
The ectomesenchyme

3. Tooth development
There are none - they are lost with eruption
Osteocytes
Odontogenesis
As a result of the apposition of cementum over dentin

4. What will the outer cells of the dental lamina differentiate into?
The permanent molars
Dentin secreting cells (odontoblats)
Common on permanent molars or cingulum of anterior teeth
The basement membrane

5. What are the major components of the tooth germ?
The enamel organ - dental papilla - dental sac
The basement membrane that seperates the enamel organ and dental papilla
Hereditary
Compressed layer of flat to cuboidal cells

6. What are the processes involved in the cap stage?
Proliferation - differentiation - morphogenesis
Induction - proliferation
Dental tissues secreted as matrix in successive layers.
Cementoblasts

7. What is the predominate process of the cap stage?
Dental follicle
Dens in dente - gemination - tubercle - and fusion
May be confused as calculus deposit on root
Morphogenesis

8. Active eruption
May be confused as calculus deposit on root
Dens in dente - gemination - tubercle - and fusion
Epithelial rests of Malassez
The actual vertical movement of the tooth

9. What is the site for the future dentioenamel junction?
Dental tissues secreted as matrix in successive layers.
The basement membrane that seperates the enamel organ and dental papilla
Tooth germ tries to divide
4 types

10. What is microdontia?
Outer
Ectoderm lining stomodeum gives rise to the oral epithelium and then to the dental lamina - adjacent to deeper ectomesenchyme - Which is influenced by the neural crest cells. Both tissues are seperated by a basement membrane
Trauma - pressure or metabolic disease
Abnormally small teeth

11. The remaining ectomesenchyme surrounding the outside of the enamel organ condenses into what?
Growth of the dental lamina into bud that penetrates growing ectomesenchyme
The dental sac
The ectomesenchyme
Yes - this is why the dentin is thicker in the mature tooth structure than the enamel

12. Where is the dental papilla originally derived from?
Dental tissues fully mineralize to their mature levels.
Osteoblasts
The ectomesenchyme - which was influenced by the neural crest cells
The enamel organ - dental papilla - dental sac

13. What are the mature cells for dentin?
Displacement of ameloblasts to root surface
The basement membrane
Dentin and alveolar bone
Only dentinal tubules with processes

14. After the enamel apposition ceases the crown area of each primary or permanent tooth what happens?
Into odontoblasts
Union of 2 adjacent tooth germs
The ameloblasts place an acellular dental cuticle on the new enamel surface
The primary tooth can now erupt into the oral cavity - the REE fuses with the oral epithelium - then enzymes from the REE disintegrate the central portion of the epithelial tissue leaving an epithelial tunnel for the tooth to erupt

15. When root formation is completed the portion of the basement membrane disintegrates its cells may become what?
Odontoblastic process
As a result of the apposition of cementum over dentin
Epithelial rests of Malassez
Enamel pearl - enamel dysplasia - and concresence

16. How is the dentinocemental junction formed?
As a result of the apposition of cementum over dentin
The successional dental lamina - an extension of the dental lamina that extends out lingually to the primary tooth germs
The cementum - PDL - and alveolar bone
A mineralized cylinder - the dentinal tubule

17. What is concrescence?
The primary tooth can now erupt into the oral cavity - the REE fuses with the oral epithelium - then enzymes from the REE disintegrate the central portion of the epithelial tissue leaving an epithelial tunnel for the tooth to erupt
The apposition of the enamel matrix
Odontogenesis
Union of root structure of two or more teeth by cementum

18. What are the clinical ramifications of supernumerary teeth?
Abnormally large teeth
Occurs commonly between the maxillary centrals - distal to the 3rd molars and premolar region. may cause crowding - failureof normal eruption and disruption of occlusion
The ectomesenchyme - which was influenced by the neural crest cells
Dentin and alveolar bone

19. The buds of the dental lamina - together with the surrounding ecto mesenchyme - will develop into what?
Tooth germ
Union of 2 adjacent tooth germs
Only dentinal tubules with processes
The cervical loop

20. What is the main process involved in the bud stage?
Hereditary in localized form. endocrine dysfunction is complete
The ectomesenchyme
The ameloblasts
Proliferation

21. What is fusion?
Pressure on the area
The ectomesenchyme - which was influenced by the neural crest cells
Union of 2 adjacent tooth germs
Bud stage

22. What is the main process involved in initiation?
The ectomesenchyme
To shape the root (or roots) and induce dentin formation in the root area so that it is continuous with coronal dentin
Proliferation - differentiation - morphogenesis
Induction

23. What is another name for the dental sac?
Proliferation - differentiation - morphogenesis
The primary tooth can now erupt into the oral cavity - the REE fuses with the oral epithelium - then enzymes from the REE disintegrate the central portion of the epithelial tissue leaving an epithelial tunnel for the tooth to erupt
Dental follicle
Dental tissues fully mineralize to their mature levels.

24. What is matrix?
Cementocytes
An extracellular substance that is partially calcified - yet serves as a framework for later calcification
Differentiation - proliferation - morphogenesis
Local or systemic or hereditary

25. What processes are involved with the apposition stage?
Dental papilla
Only dentinal tubules with processes
Induction - proliferation
The bud stage

26. The stage named for extensive proliferation of the dental lamina into oval masses penetrating into the ectomesenchyme?
The ectomesenchyme - which was influenced by the neural crest cells
Growth of the dental lamina into bud that penetrates growing ectomesenchyme
After the crown is completely shaped and the tooth is starting to erupt into the oral cavity
The bud stage

27. What is the embryological background for enamel?
Outer
Induction - proliferation
Union of root structure of two or more teeth by cementum
Enamel organ

28. What happens during the bud stage?
Growth of the dental lamina into bud that penetrates growing ectomesenchyme
Dental tissues fully mineralize to their mature levels.
Enamel organ
Odontoblasts

29. When the undifferentiated cells of the dental sac come into contact with the root dentin they differentiate into what?
8th week
Hereditary - endocrine dysfunction - systemic disease - excess radiation exposure
Cementoblasts
The ectomesenchyme

30. What type of tissue is enamel?
Tooth germ tries to divide
Epithelial
Only dentinal tubules with processes
Initiation stage

31. What are the etiological factors for micro/macrodontia?
Pressure on the area
Connective
Dentin and alveolar bone
Hereditary in localized form. endocrine dysfunction is complete

32. What are the formative cells for cementum?
Hereditary
Cementoblasts
The enamel - dentin - and cementum are secreted in successive layers
Sphere of enamel on root

33. What hard tissue is innervated by nerves?
Dentin and alveolar bone
The disintegration of the basement membrane allows the preameloblasts to come into contact with the newly formed predentin
8th week
6th to 7th weeks

34. The preameloblasts induce dental papilla cells to differentiate into what?
Into odontoblasts
The primordium of the pulp
Induction - proliferation
Pressure on the area

35. Where is the enamal organ originally derived from?
Dentinogenesis - Which is the apposition of dentin matrix - or predentin - on the other side of the basement membrane
The dental sac
Imbrication lines of von Ebner
The ectoderm

36. What cell bodies are involved in the eruption and mineralization process but will be lost after eruption?
It disintegrates as the developing oral mucosa comes to line the oral cavity
Osteoblasts
The ameloblasts
The bud stage

37. What are the clinical ramifications of fusion?
The basement membrane
Induction
Dental tissues fully mineralize to their mature levels.
Large tooth with two pulp cavities. one fewer tooth in dentition. may cause problems in appearance and spacing

38. What is the outer portion of the ectoderm in the initiation stage?
Oral epithelium
There are none - they are lost with eruption
Proliferation - differentiation - morphogenesis
Common on permanent molars or cingulum of anterior teeth

39. The stellate reticulum is located inner or outer?
Outer
Differentiation
The basement membrane that seperates the enamel organ and dental papilla
A bilayer rim that consists only IEE and OEE

40. When does the process of root development take place?
The cementum - PDL - and alveolar bone
After the crown is completely shaped and the tooth is starting to erupt into the oral cavity
Permanent teeth formed with primary predecessors - the anterior teeth and the premolars
The enamel - dentin - and cementum are secreted in successive layers

41. What are the etiological factors for supernumerary teeth?
Hereditary
Dentin secreting cells (odontoblats)
Odontoblasts
Faulty development of enamel from interference involving ameloblasts

42. When the inner epithelial epithelium columnar cells elongate and repolarize they differentiate into what?
Preameloblasts
6th to 7th weeks
Alveolar bone
Arrest and reversal lines

43. What processes are involved in the bell stage?
Induction
Union of 2 adjacent tooth germs
Differentiation - proliferation - morphogenesis
The permanent molars

44. When does dens in dente occur?
The primary tooth can now erupt into the oral cavity - the REE fuses with the oral epithelium - then enzymes from the REE disintegrate the central portion of the epithelial tissue leaving an epithelial tunnel for the tooth to erupt
During the cap stage
Lines of Retzuis
Only dentinal tubules with processes

45. What are the development disturbances of the apposition and maturation stages?
Preameloblasts
Enamel pearl - enamel dysplasia - and concresence
Common with permanent maxillary molars
Compressed layer of flat to cuboidal cells

46. What is the time span for the bell stage?
It disintegrates as the developing oral mucosa comes to line the oral cavity
11th to 12th weeks
Proliferation
The permanent molars

47. What are the clinical ramifications of enamel pearl?
Faulty development of enamel from interference involving ameloblasts
Hereditary in localized form. endocrine dysfunction is complete
Dentin secreting cells (odontoblats)
May be confused as calculus deposit on root

48. What are the odontoblastic processes is contained in what?
A mineralized cylinder - the dentinal tubule
Abnormally large teeth
As a result of the apposition of cementum over dentin
Traumatic injury or crowding of teeth

49. What is an enamel pearl?
Pitting or intrinsic color changes in enamel. changes in thickness of enamel possible. problems in function and aesthetics
Sphere of enamel on root
During the cap stage
Hereditary - endocrine dysfunction - systemic disease - excess radiation exposure

50. What is cementogenisis?
Apposition of the cementum
In the cap stage
11th to 12th weeks
The ectomesenchyme