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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 is fusion?
Union of 2 adjacent tooth germs
There is unequal growth in different parts of the tooth bud
Proliferation
The enamel organ is compressed

2. What are succedaneous teeth?
Permanent teeth formed with primary predecessors - the anterior teeth and the premolars
Apposition of the cementum
May cause disruption of occlusion and aesthetic problems - may need partial or full dentures - bridges - and/or implants
There is unequal growth in different parts of the tooth bud

3. What are the clinical ramifications?
Common on permanent molars or cingulum of anterior teeth
Induction
Displacement of ameloblasts to root surface
The enamel - dentin - and cementum are secreted in successive layers

4. When root formation is completed the portion of the basement membrane disintegrates its cells may become what?
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
Epithelial rests of Malassez
May be confused as calculus deposit on root
Ameloblasts

5. What are the incremental lines for cementum and alveolar bone?
Arrest and reversal lines
4 types
11th to 12th weeks
Union of root structure of two or more teeth by cementum

6. How is the dentinocemental junction formed?
The ectomesenchyme - which was influenced by the neural crest cells
Enamel organ
Local or systemic or hereditary
As a result of the apposition of cementum over dentin

7. Tooth development
Odontogenesis
8th week
Traumatic injury or crowding of teeth
Odontoblastic process

8. What happens when the reduced enamel epithelium is created?
Development of one or more extra teeth
Odontogenesis
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 Tomes' process - a tapered portion of each ameloblast that faces the disintegrating basement membrane

9. What are the etiological factors for dens in dente and gemination?
It disintegrates as the developing oral mucosa comes to line the oral cavity
A mineralized cylinder - the dentinal tubule
Hereditary
The dental lamina

10. The preameloblasts induce dental papilla cells to differentiate into what?
Arrest and reversal lines
Into odontoblasts
In the cap stage
Abnormally small teeth

11. What are the resorptive cells for enamel - dentin - cementum and alveolar bone?
Differentiation of enamel organ into bell with four cell types and dental papilla into two cell types.
Displacement of ameloblasts to root surface
Odontoclasts
Future dentin and pulp tissue

12. Where is the dental sac originally derived from?
Cuboidal cells
Tooth germ tries to divide
The ectomesenchyme
During the cap stage

13. What is tubercle?
9th to 10th weeks
Extra cusp due to effects on enamel organ
It disintegrates as the developing oral mucosa comes to line the oral cavity
The cementum - PDL - and alveolar bone

14. What are the incremental lines for dentin?
Imbrication lines of von Ebner
Enamel
Faulty development of enamel from interference involving ameloblasts
Extra cusp due to effects on enamel organ

15. What is cementogenisis?
The enamel - dentin - and cementum are secreted in successive layers
The ectomesenchyme
Apposition of the cementum
Outer

16. What is the outer portion of the ectoderm in the initiation stage?
The dental sac
The apposition of the enamel matrix
Oral epithelium
Union of 2 adjacent tooth germs

17. What is another name for the dental sac?
An extracellular substance that is partially calcified - yet serves as a framework for later calcification
Only dentinal tubules with processes
Dental follicle
Hereditary

18. What is the predominate process in the bell stage?
The enamel organ
Enamel organ
The basement membrane
Differentiation

19. 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
The enamel organ - dental papilla - dental sac
Induction - proliferation
Enamel pearl - enamel dysplasia - and concresence

20. What are the incremental lines for enamel?
To shape the root (or roots) and induce dentin formation in the root area so that it is continuous with coronal dentin
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.
Lines of Retzuis
The successional dental lamina - an extension of the dental lamina that extends out lingually to the primary tooth germs

21. What are the mature cells for alveolar bone?
Osteocytes
Hereditary
Epithelial rests of Malassez
Yes - this is why the dentin is thicker in the mature tooth structure than the enamel

22. Active eruption
The ectomesenchyme
The actual vertical movement of the tooth
May be confused as calculus deposit on root
Dental tissues secreted as matrix in successive layers.

23. What are the clinical ramifications of enamel pearl?
May be confused as calculus deposit on root
Tall columnar cells
When the gingiva recedes and no actual tooth movement takes place
Osteoblasts

24. What do the odontoblasts do?
Differentiation of enamel organ into bell with four cell types and dental papilla into two cell types.
Occurs commonly between the maxillary centrals - distal to the 3rd molars and premolar region. may cause crowding - failureof normal eruption and disruption of occlusion
Dentinogenesis - Which is the apposition of dentin matrix - or predentin - on the other side of the basement membrane
The enamel organ is compressed

25. Odontoblasts leave attached cellular extensions in the length of the predentin called what?
Odontoblastic process
8th week
Apposition of the cementum
The ectoderm

26. What are the mature cells for dentin?
Only dentinal tubules with processes
11th to 12th weeks
The basement membrane
Epithelial

27. What are the clinical ramifications of supernumerary teeth?
4 types
The ectomesenchyme
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 cervical loop

28. The oral epithelium is induced by the ectomesenchyme to produce what?
Proliferation
The dental lamina
Differentiation of enamel organ into bell with four cell types and dental papilla into two cell types.
Extra cusp due to effects on enamel organ

29. What are the etiological factors of tubercle?
Enamel
Trauma - pressure or metabolic disease
The dental sac
4 types

30. What is macrodontia?
Abnormally large teeth
Dental follicle
Commonly involves permanent maxillary lateral incisor and 3rd molars
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

31. Where is the enamal organ originally derived from?
Alveolar bone
Extra cusp due to effects on enamel organ
There are none - they are lost with eruption
The ectoderm

32. What is the main process involved in initiation?
Odontogenesis
Enamel
Absence of single or multiple teeth
Induction

33. What happens during the bud stage?
Growth of the dental lamina into bud that penetrates growing ectomesenchyme
Dental follicle
Osteocytes
May cause disruption of occlusion and aesthetic problems - may need partial or full dentures - bridges - and/or implants

34. What will the outer cells of the dental lamina differentiate into?
The ectomesenchyme
Common with permanent maxillary molars
Dentin secreting cells (odontoblats)
Common on permanent molars or cingulum of anterior teeth

35. What stage does anodontia occur?
Maturation
Initiation stage
Commonly affects the permanent maxillary lateral incisor. tooth may have deep lingual pit and need endodontic therapy
There is unequal growth in different parts of the tooth bud

36. What stage does supernumerary teeth occur?
Into odontoblasts
The permanent molars
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
Initiation

37. What will the dental sac give rise to?
Differentiation of enamel organ into bell with four cell types and dental papilla into two cell types.
The cementum - PDL - and alveolar bone
Cementocytes
When the gingiva recedes and no actual tooth movement takes place

38. What are the etiological factors for fusion?
The ectomesenchyme - which was influenced by the neural crest cells
Occurs commonly between the maxillary centrals - distal to the 3rd molars and premolar region. may cause crowding - failureof normal eruption and disruption of occlusion
Osteocytes
Pressure on the area

39. What are the development disturbances of the apposition and maturation stages?
Enamel pearl - enamel dysplasia - and concresence
The ectomesenchyme
Enamel organ invaginates into the dental papilla
Sphere of enamel on root

40. What hard tissue has vascularity?
The dental sac
Odontoclasts
Initiation
Alveolar bone

41. When does dens in dente occur?
The disintegration of the basement membrane allows the preameloblasts to come into contact with the newly formed predentin
There is unequal growth in different parts of the tooth bud
During the cap stage
Dentin and alveolar bone

42. What wll the inner enamel epithelium differentiate into?
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
A bilayer rim that consists only IEE and OEE
Bud stage
Enamel secreting cells (ameloblasts)

43. What is the function of the Hertwig's epithelial root sheath?
Tooth germ tries to divide
During the cap stage
Common with permanent maxillary molars
To shape the root (or roots) and induce dentin formation in the root area so that it is continuous with coronal dentin

44. What are the clinical ramifications of micro/macrodontia?
The ectomesenchyme - which was influenced by the neural crest cells
Commonly involves permanent maxillary lateral incisor and 3rd molars
Dentinogenesis - Which is the apposition of dentin matrix - or predentin - on the other side of the basement membrane
The successional dental lamina - an extension of the dental lamina that extends out lingually to the primary tooth germs

45. What are the clinical ramifications of enamel dysplasia?
The ectomesenchyme
Pitting or intrinsic color changes in enamel. changes in thickness of enamel possible. problems in function and aesthetics
A mineralized cylinder - the dentinal tubule
Hereditary

46. How is the reduced enamel epithelium created?
Oral epithelium
Enamel pearl - enamel dysplasia - and concresence
The enamel organ is compressed
Dental papilla

47. What is concrescence?
Enamel pearl - enamel dysplasia - and concresence
The successional dental lamina - an extension of the dental lamina that extends out lingually to the primary tooth germs
Union of root structure of two or more teeth by cementum
During the cap stage

48. What are the clinical ramifications of concrescence?
The enamel - dentin - and cementum are secreted in successive layers
Dental papilla
Hereditary - endocrine dysfunction - systemic disease - excess radiation exposure
Common with permanent maxillary molars

49. What is amelogenisis?
Tooth germ
The apposition of the enamel matrix
Epithelial rests of Malassez
Dental tissues secreted as matrix in successive layers.

50. When does the tooth bud become a tooth germ?
Osteoblasts
In the cap stage
Common with permanent maxillary molars
Yes - this is why the dentin is thicker in the mature tooth structure than the enamel