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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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1. What causes the induction of the preameloblasts to differentiate into ameloblasts?
A bilayer rim that consists only IEE and OEE
Faulty development of enamel from interference involving ameloblasts
The disintegration of the basement membrane allows the preameloblasts to come into contact with the newly formed predentin
The tooth germ

2. What are the clinical ramifications of fusion?
Oral epithelium
Large tooth with two pulp cavities. one fewer tooth in dentition. may cause problems in appearance and spacing
The actual vertical movement of the tooth
8th week

3. What are the incremental lines for dentin?
Union of root structure of two or more teeth by cementum
Imbrication lines of von Ebner
The ectomesenchyme
Hereditary

4. What happens during the maturation stage?
Dental tissues fully mineralize to their mature levels.
Oral epithelium
The successional dental lamina - an extension of the dental lamina that extends out lingually to the primary tooth germs
The outer enamel epithelium

5. What is the embryological background for enamel?
Dental papilla
Differentiation
Enamel organ
Epithelial rests of Malassez

6. What are the mature cells for dentin?
Hereditary
Faulty development of enamel from interference involving ameloblasts
Dentin secreting cells (odontoblats)
Only dentinal tubules with processes

7. What are the clinical ramifications?
Common on permanent molars or cingulum of anterior teeth
Preameloblasts
The cervical loop
Dentin secreting cells (odontoblats)

8. What are the incremental lines for enamel?
Lines of Retzuis
Odontoclasts
Common with permanent maxillary molars
The outer enamel epithelium

9. What happens during the appositional stage?
Hereditary - endocrine dysfunction - systemic disease - excess radiation exposure
The basement membrane that seperates the enamel organ and dental papilla
The stellate reticulum
The enamel - dentin - and cementum are secreted in successive layers

10. Which layer in the bell stage has star shaped cells?
Only dentinal tubules with processes
As a result of the apposition of cementum over dentin
The stellate reticulum
Common with permanent maxillary molars

11. What are the formative cells for alveolar bone?
Lines of Retzuis
An extracellular substance that is partially calcified - yet serves as a framework for later calcification
Osteoblasts
Growth of the dental lamina into bud that penetrates growing ectomesenchyme

12. What are the etiological factors for fusion?
A mineralized cylinder - the dentinal tubule
Proliferation
The basement membrane
Pressure on the area

13. What are the formative cells for enamel?
May cause disruption of occlusion and aesthetic problems - may need partial or full dentures - bridges - and/or implants
Ameloblasts
Odontoblastic process
There are none - they are lost with eruption

14. What are the etiological factors for anodontia?
Abnormally small teeth
The dental lamina
Hereditary - endocrine dysfunction - systemic disease - excess radiation exposure
Local or systemic or hereditary

15. When root formation is completed the portion of the basement membrane disintegrates its cells may become what?
Epithelial rests of Malassez
Epithelial
Hereditary in localized form. endocrine dysfunction is complete
Displacement of ameloblasts to root surface

16. What are succedaneous teeth?
Dens in dente - gemination - tubercle - and fusion
Permanent teeth formed with primary predecessors - the anterior teeth and the premolars
Cementocytes
The successional dental lamina - an extension of the dental lamina that extends out lingually to the primary tooth germs

17. What are the formative cells for cementum?
May be confused as calculus deposit on root
Cementoblasts
Enamel organ forms into cap - surrounding mass of dental papilla from the ectomesenchyme and surrounded by mass of dental sac also from the ectomesenchyme. Formation of the tooth germ.
Osteocytes

18. What kind of cells reside in the stratum intermediate?
An extracellular substance that is partially calcified - yet serves as a framework for later calcification
Commonly affects the permanent maxillary lateral incisor. tooth may have deep lingual pit and need endodontic therapy
Dental papilla
Compressed layer of flat to cuboidal cells

19. When does dens in dente occur?
There are none - they are lost with eruption
As a result of the apposition of cementum over dentin
During the cap stage
The ectomesenchyme - which was influenced by the neural crest cells

20. Do odontoblasts start their secretion of matrix before the ameloblasts?
Growth of the dental lamina into bud that penetrates growing ectomesenchyme
Yes - this is why the dentin is thicker in the mature tooth structure than the enamel
Pressure on the area
The enamel organ is compressed

21. What happens during initiation?
As a result of the apposition of cementum over dentin
Commonly affects the permanent maxillary lateral incisor. tooth may have deep lingual pit and need endodontic therapy
The Tomes' process - a tapered portion of each ameloblast that faces the disintegrating basement membrane
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

22. What is the cementum matrix called?
The primordium of the pulp
Large tooth with two pulp cavities. one fewer tooth in dentition. may cause problems in appearance and spacing
Cementoid
May cause disruption of occlusion and aesthetic problems - may need partial or full dentures - bridges - and/or implants

23. What are the etiological factors of concrescence?
Trauma - pressure or metabolic disease
Odontogenesis
Union of root structure of two or more teeth by cementum
Traumatic injury or crowding of teeth

24. What is the primordium of the tooth?
9th to 10th weeks
The basement membrane
Yes - this is why the dentin is thicker in the mature tooth structure than the enamel
The tooth germ

25. When the undifferentiated cells of the dental sac come into contact with the root dentin they differentiate into what?
Cementoblasts
The basement membrane
Apposition of the cementum
The dental sac

26. What stage does supernumerary teeth occur?
Initiation
Dentinogenesis - Which is the apposition of dentin matrix - or predentin - on the other side of the basement membrane
Tooth germ
Dental papilla

27. What is the time span for the bell stage?
11th to 12th weeks
Common on permanent molars or cingulum of anterior teeth
During the cap stage
The ectoderm

28. What is the inner mass in the cap stage that forms a concavity of the enamel organ?
Dental papilla
The bud stage
The outer enamel epithelium - the inner enamel epithelium - the stellate reticulum - and the stratum intermedium
During the cap stage

29. Where is the dental papilla originally derived from?
Dental follicle
The ectomesenchyme - which was influenced by the neural crest cells
There is unequal growth in different parts of the tooth bud
Induction

30. Passive eruption
When the gingiva recedes and no actual tooth movement takes place
The basement membrane that seperates the enamel organ and dental papilla
Yes - this is why the dentin is thicker in the mature tooth structure than the enamel
Enamel organ forms into cap - surrounding mass of dental papilla from the ectomesenchyme and surrounded by mass of dental sac also from the ectomesenchyme. Formation of the tooth germ.

31. How many types of cells are found in the enamel organ in the bell stage?
4 types
The basement membrane that seperates the enamel organ and dental papilla
Dentinogenesis - Which is the apposition of dentin matrix - or predentin - on the other side of the basement membrane
Maturation

32. What do the odontoblasts do?
Faulty development of enamel from interference involving ameloblasts
Dentinogenesis - Which is the apposition of dentin matrix - or predentin - on the other side of the basement membrane
The cementum - PDL - and alveolar bone
Enamel pearl - enamel dysplasia - and concresence

33. What are entrapped cementoblasts called?
Cementocytes
The enamel - dentin - and cementum are secreted in successive layers
The outer cells of the dental papilla and the central cells of the dental papilla
Arrest and reversal lines

34. What are the etiological factors for micro/macrodontia?
Common on permanent molars or cingulum of anterior teeth
Hereditary in localized form. endocrine dysfunction is complete
The enamel - dentin - and cementum are secreted in successive layers
Growth of the dental lamina into bud that penetrates growing ectomesenchyme

35. What is the structure responsible for root development?
The primordium of the pulp
Epithelial rests of Malassez
The cervical loop
Enamel pearl - enamel dysplasia - and concresence

36. What happens during the apposition stage?
Dental tissues secreted as matrix in successive layers.
The ectomesenchyme - which was influenced by the neural crest cells
The stellate reticulum
Cuboidal cells

37. What stage does the dental tissues subsequently fully mineralize
Maturation
Dental papilla
8th week
Compressed layer of flat to cuboidal cells

38. What will the outer cells of the dental lamina differentiate into?
Osteoblasts
Outer
Dentin secreting cells (odontoblats)
May be confused as calculus deposit on root

39. In the cap stage the tooth bud does not grow - what happens?
Bud stage
There is unequal growth in different parts of the tooth bud
Cementoblasts
Differentiation

40. What wll the inner enamel epithelium differentiate into?
The successional dental lamina - an extension of the dental lamina that extends out lingually to the primary tooth germs
Differentiation - proliferation - morphogenesis
Enamel secreting cells (ameloblasts)
Epithelial rests of Malassez

41. What hard tissue is innervated by nerves?
Hereditary in localized form. endocrine dysfunction is complete
The ameloblasts place an acellular dental cuticle on the new enamel surface
Dentin and alveolar bone
There is unequal growth in different parts of the tooth bud

42. Odontoblasts leave attached cellular extensions in the length of the predentin called what?
Induction - proliferation
Odontoblastic process
Absence of single or multiple teeth
The apposition of the enamel matrix

43. What happens when the reduced enamel epithelium is created?
Arrest and reversal lines
Pressure on the area
Initiation stage
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

44. What is the important acelluar structure that seperates the oral epithelium and the ectomesenchyme?
Odontogenesis
The ameloblasts place an acellular dental cuticle on the new enamel surface
The basement membrane
The stellate reticulum

45. What hard tissue is can not have tissue formation after eruption?
Enamel
The enamel organ
To shape the root (or roots) and induce dentin formation in the root area so that it is continuous with coronal dentin
11th to 12th weeks

46. When the inner epithelial epithelium columnar cells elongate and repolarize they differentiate into what?
Local or systemic or hereditary
Dental papilla
Occurs commonly between the maxillary centrals - distal to the 3rd molars and premolar region. may cause crowding - failureof normal eruption and disruption of occlusion
Preameloblasts

47. What is the time span for initiation?
Faulty development of enamel from interference involving ameloblasts
Dentinogenesis - Which is the apposition of dentin matrix - or predentin - on the other side of the basement membrane
6th to 7th weeks
The outer enamel epithelium

48. What are the resorptive cells for enamel - dentin - cementum and alveolar bone?
Extra cusp due to effects on enamel organ
The stellate reticulum
A mineralized cylinder - the dentinal tubule
Odontoclasts

49. What type of tissue is dentin - cementum - and alveolar bone?
Dentin secreting cells (odontoblats)
Connective
The ectomesenchyme - which was influenced by the neural crest cells
Induction - proliferation

50. What are the etiological factors for supernumerary teeth?
Hereditary
Dental papilla
Morphogenesis
Growth of the dental lamina into bud that penetrates growing ectomesenchyme