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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 is the function of the Hertwig's epithelial root sheath?
Union of root structure of two or more teeth by cementum
Growth of the dental lamina into bud that penetrates growing ectomesenchyme
Cuboidal cells
To shape the root (or roots) and induce dentin formation in the root area so that it is continuous with coronal dentin

2. What are the clinical ramifications of micro/macrodontia?
Connective
Commonly involves permanent maxillary lateral incisor and 3rd molars
Faulty development of enamel from interference involving ameloblasts
Imbrication lines of von Ebner

3. What are the mature cells for enamel?
Pressure on the area
Odontoblasts
There are none - they are lost with eruption
Alveolar bone

4. What are the incremental lines for enamel?
Lines of Retzuis
In the cap stage
Cementocytes
Commonly involves permanent maxillary lateral incisor and 3rd molars

5. What is fusion?
Union of 2 adjacent tooth germs
Enamel
Dental papilla
A bilayer rim that consists only IEE and OEE

6. The preameloblasts induce dental papilla cells to differentiate into what?
Bud stage
Cuboidal cells
The disintegration of the basement membrane allows the preameloblasts to come into contact with the newly formed predentin
Into odontoblasts

7. What are the clinical ramifications of fusion?
Dental papilla
Hereditary
Large tooth with two pulp cavities. one fewer tooth in dentition. may cause problems in appearance and spacing
Yes - this is why the dentin is thicker in the mature tooth structure than the enamel

8. What hard tissue is innervated by nerves?
Cementocytes
The primordium of the pulp
Dentin and alveolar bone
The basement membrane that seperates the enamel organ and dental papilla

9. How many types of cells are found in the enamel organ in the bell stage?
4 types
The actual vertical movement of the tooth
Traumatic injury or crowding of teeth
Odontoblasts

10. What stage does the dental tissues subsequently fully mineralize
Osteoblasts
Growth of the dental lamina into bud that penetrates growing ectomesenchyme
The ectomesenchyme
Maturation

11. What are the development disturbances of the apposition and maturation stages?
It disintegrates as the developing oral mucosa comes to line the oral cavity
Enamel pearl - enamel dysplasia - and concresence
Differentiation - proliferation - morphogenesis
Development of one or more extra teeth

12. What are the etiological factors for anodontia?
The disintegration of the basement membrane allows the preameloblasts to come into contact with the newly formed predentin
Hereditary - endocrine dysfunction - systemic disease - excess radiation exposure
Common on permanent molars or cingulum of anterior teeth
The basement membrane

13. What are the etiological factors for dens in dente and gemination?
9th to 10th weeks
Hereditary
Induction
There is unequal growth in different parts of the tooth bud

14. What causes the induction of the preameloblasts to differentiate into ameloblasts?
Hereditary
The disintegration of the basement membrane allows the preameloblasts to come into contact with the newly formed predentin
Differentiation - proliferation - morphogenesis
Dental papilla

15. What is the embryological background for enamel?
A bilayer rim that consists only IEE and OEE
Development of one or more extra teeth
There are none - they are lost with eruption
Enamel organ

16. What wll the inner enamel epithelium differentiate into?
May be confused as calculus deposit on root
Dental papilla
Enamel secreting cells (ameloblasts)
Common with permanent maxillary molars

17. What are the formative cells for dentin?
The ectomesenchyme
Enamel organ
Dens in dente - gemination - tubercle - and fusion
Odontoblasts

18. Where is the dental sac originally derived from?
In the cap stage
Proliferation - differentiation - morphogenesis
Extra cusp due to effects on enamel organ
The ectomesenchyme

19. What are the formative cells for cementum?
Cementoblasts
Connective
Enamel secreting cells (ameloblasts)
The enamel organ is compressed

20. What stage does supernumerary teeth occur?
Initiation
The tooth germ
Dentin secreting cells (odontoblats)
Traumatic injury or crowding of teeth

21. What is microdontia?
Abnormally small teeth
Osteoblasts
The cervical loop
Outer

22. What is concrescence?
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.
In the cap stage
Union of root structure of two or more teeth by cementum
Cementoblasts

23. What are the clinical ramifications of concrescence?
Differentiation - proliferation - morphogenesis
Enamel secreting cells (ameloblasts)
Common with permanent maxillary molars
The permanent molars

24. The oral epithelium is induced by the ectomesenchyme to produce what?
Epithelial
The dental lamina
The enamel - dentin - and cementum are secreted in successive layers
Initiation

25. What is dens in dente?
Dentin and alveolar bone
Alveolar bone
Enamel organ invaginates into the dental papilla
As a result of the apposition of cementum over dentin

26. What is gemination?
Tooth germ tries to divide
Union of root structure of two or more teeth by cementum
The outer enamel epithelium
The outer cells of the dental papilla and the central cells of the dental papilla

27. Do odontoblasts start their secretion of matrix before the ameloblasts?
Traumatic injury or crowding of teeth
Differentiation - proliferation - morphogenesis
Cementocytes
Yes - this is why the dentin is thicker in the mature tooth structure than the enamel

28. What hard tissue has vascularity?
Maturation
The apposition of the enamel matrix
Alveolar bone
Common on permanent molars or cingulum of anterior teeth

29. Where is the enamel matrix secreted from by the ameloblasts?

30. What happens during the apposition stage?
Maturation
The basement membrane that seperates the enamel organ and dental papilla
Dental tissues secreted as matrix in successive layers.
The outer enamel epithelium - the inner enamel epithelium - the stellate reticulum - and the stratum intermedium

31. What is enamel dysplasia?
Faulty development of enamel from interference involving ameloblasts
Odontoblastic process
Tooth germ
When the gingiva recedes and no actual tooth movement takes place

32. What happens during initiation?
Union of 2 adjacent tooth germs
The actual vertical movement of the tooth
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
The ectomesenchyme

33. What happens during the bell stage?
Differentiation of enamel organ into bell with four cell types and dental papilla into two cell types.
A mineralized cylinder - the dentinal tubule
It disintegrates as the developing oral mucosa comes to line the oral cavity
Dental papilla

34. What happens during the bud stage?
Growth of the dental lamina into bud that penetrates growing ectomesenchyme
Commonly involves permanent maxillary lateral incisor and 3rd molars
Absence of single or multiple teeth
Enamel organ

35. What are the mature cells for alveolar bone?
Outer
During the cap stage
Osteocytes
4 types

36. What are the clinical ramifications of gemination?

37. What is anodontia?
Abnormally small teeth
Commonly affects the permanent maxillary lateral incisor. tooth may have deep lingual pit and need endodontic therapy
Absence of single or multiple teeth
Ameloblasts

38. What is the predominate process in the bell stage?
Enamel secreting cells (ameloblasts)
Traumatic injury or crowding of teeth
Morphogenesis
Differentiation

39. The buds of the dental lamina - together with the surrounding ecto mesenchyme - will develop into what?
Tooth germ
Enamel secreting cells (ameloblasts)
Maturation
The disintegration of the basement membrane allows the preameloblasts to come into contact with the newly formed predentin

40. What are the major components of the tooth germ?
Large single rooted tooth with one pulp cavity and exhibits 'twinning' in crown area. normal number of teeth in dentition. may cause problems in appearance and spacing
Proliferation
The enamel organ - dental papilla - dental sac
Cementocytes

41. Odontoblasts leave attached cellular extensions in the length of the predentin called what?
Development of one or more extra teeth
Traumatic injury or crowding of teeth
Odontoblastic process
Tooth germ

42. When does dens in dente occur?
Cementocytes
Cementoid
Displacement of ameloblasts to root surface
During the cap stage

43. What happens during the cap stage?
The outer cells of the dental papilla and the central cells of the dental papilla
Enamel organ
Abnormally large teeth
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.

44. What do the odontoblasts do?
Dentinogenesis - Which is the apposition of dentin matrix - or predentin - on the other side of the basement membrane
9th to 10th weeks
Bud stage
Ameloblasts

45. What are the 2 layers in the dental papilla within the concavity of the enamel organ?
The outer cells of the dental papilla and the central cells of the dental papilla
Initiation stage
9th to 10th weeks
Union of root structure of two or more teeth by cementum

46. What are the etiological factors for micro/macrodontia?
The enamel organ
Tall columnar cells
Hereditary in localized form. endocrine dysfunction is complete
Pitting or intrinsic color changes in enamel. changes in thickness of enamel possible. problems in function and aesthetics

47. What are the formative cells for alveolar bone?
Odontoblasts
Displacement of ameloblasts to root surface
The outer cells of the dental papilla and the central cells of the dental papilla
Osteoblasts

48. What are the incremental lines for dentin?
The successional dental lamina - an extension of the dental lamina that extends out lingually to the primary tooth germs
As a result of the apposition of cementum over dentin
Imbrication lines of von Ebner
Differentiation of enamel organ into bell with four cell types and dental papilla into two cell types.

49. What are the clinical ramifications of supernumerary teeth?
Enamel secreting cells (ameloblasts)
Dentin and alveolar bone
Common with permanent maxillary molars
Occurs commonly between the maxillary centrals - distal to the 3rd molars and premolar region. may cause crowding - failureof normal eruption and disruption of occlusion

50. When the inner epithelial epithelium columnar cells elongate and repolarize they differentiate into what?
Preameloblasts
The tooth germ
Dental tissues fully mineralize to their mature levels.
The permanent molars