Disorders of teeth Flashcards

1
Q

What are the 3 distinct stages of normal dental development?

A

Pre eruptive, prefunctional and functional

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2
Q

What is the pre-eruptive stage?

A

Initiation of development to the page of crown completion:

  • initiation = dental lamina + tooth germs
  • morphogenesis = shape of tooth
  • histogenesis = mineralised hard tissues
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3
Q

What is pre-functional stage?

A

eruption

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4
Q

What is the functional stage?

A

maintenance of occlusion

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5
Q

What is eruption?

A

The process by which a tooth moves from its developmental position to a functional position in the mouth (begins once the root befits to form)

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6
Q

How many teeth are there in the primary dentition?

A

20

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7
Q

How many teeth are there in the permanent dentition?

A

32

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8
Q

What is the normal eruption date for the a’s?

A

6-12 months

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9
Q

What is the normal eruption dates for the b’s?

A

9-16 months

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10
Q

What is the normal eruption dates for the c’s?

A

16-23 months

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11
Q

What is the normal eruption dates for the d’s?

A

13-16 months

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12
Q

What is the normal eruption dates for the e’s?

A

23-31 months

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13
Q

What is the normal eruption dates for the 1’s?

A

6-8 y/o

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14
Q

What is the normal eruption dates for the 2’s?

A

7-9 y/o

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15
Q

What is the normal eruption dates for the 3’s?

A

9-12 y/o

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16
Q

What is the normal eruption dates for the 4’s?

A

10-12y/o

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17
Q

What is the normal eruption dates for the 5’s?

A

10-12y/o

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18
Q

What is the normal eruption dates for the 6’s?

A

6-7 y/o

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19
Q

What is the normal eruption dates for the 7’s?

A

12-13 y/o

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20
Q

What is the normal eruption dates for the 8’s?

A

18-25 y/o

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21
Q

What is hyperdontia?

A

too many teeth

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22
Q

What are the two types of hyperdontia?

A

Supernumerary and supplemental

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23
Q

What are supernumerary teeth?

A

Additional tooth with abnormalities in the shape, names are based on position in oral cavity (mesodens- in midline, paramolar - to side of, normally buccal aspect, distomolar - behind the upper 8’s)
- 1-3% population in permanent dentition, F>M

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24
Q

What are supplemental teeth?

A

Additional teeth with normal shape

Upper 2> lower 5 > upper 5

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25
Q

What is hypodontia?

A

missing teeth

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26
Q

Tell me more about hypodontia:

A
  • congenital loss
  • 3-7% population
  • F > M
  • Uncommon in deciduous
  • Usually affects those last in series to develop (8’s, 5’s and 2’s)
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27
Q

What is anodontia?

A

Complete absence of teeth = extremely rare (permanent dentition fails to form - no dental lamina)
= usually syndrome related

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28
Q

What are the 6 disorders in eruption and exfoliation of teeth?

A
  1. premature eruption
  2. delayed/retarded eruption
  3. premature loss
  4. persistence of deciduous
  5. impaction
  6. reimpaction
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29
Q

What are natal teeth?

A

Present at birth

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30
Q

What are neonatal teeth?

A

Teeth that erupt within the first 30 days

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31
Q

Tell me more about premature eruption of teeth:

A
  • Occurs 1: 4000 live births
  • 1 or 2 central incisors
  • 4 x more frequent in mandible
  • normal tooth germs but developed superficially - early eruption
  • radicular dentine and cementum irregular structure due to mobility in jaw
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32
Q

What is the management for premature eruption of teeth?

A
  • extract or spontaneous loss
  • if table enough can be left to continue to develop
    BUT risk of inhalation or difficulty breast feeding (mother)
33
Q

What is delayed tooth eruption associated with?

A

Premature babies, trauma (displacement of tooth germs), nutritional deficiency, chromosomal abnormalities and endocrinopathies (hypothyroidism)

34
Q

What is premature loss associated with?

A

Dental caries, chronic periodontal disease and diseases e.g. hypophosphatasia

35
Q

What is hypophospatasia?

A
  • Rare inherited bone disease
  • inborn error of metabolism
  • low activity of tissue non-specific isoenzyme of alkaline phosphatase
  • deformities of skeleton
  • disturbed cementum formation /aplasia (n.b. normally attached to PDL = without = tooth mobility and loss of tooth)
  • children lose teeth before 5 y/o
36
Q

What is persistence of deciduous teeth often associated with?

A

Fair of eruption of the permanent successor

37
Q

What is local persistence of deciduous teeth?

A

Misplaced or displaced teeth

38
Q

What is generalised persistence of deciduous teeth?

A

Entire dentition (rare e.g cleidocranial dysplasia or cherubism)

39
Q

What is cherubism?

A

Familial multilocular cystic disease (genetic, autosomal dominant) = disruption of signalling pathways associated with maintenance of bone -> normal at birth with progressive facial deformity (bilateral swelling of mandible, eyes upturned to heaven and lack of eruption)
Radiographically: multinodular cystic radiolucencies with absent/unerupted teeth

40
Q

What is impaction of teeth?

A

Where a tooth remains unerupted or partially erupted in the time when it would normally have erupted

41
Q

How many teeth does impaction effect?

A

1 or several

42
Q

Tell me more about impaction of teeth:

A
  • can be symmetrical
  • is rare in primary teeth
  • permanent teeth most likely affected: 3rd molars, mandibular premolars and maxillary canines
43
Q

What are the causes of impaction of teeth?

A
  • abnormal position of tooth germ (esp. wisdom teeth)
  • lack of space
  • supernumerary teeth
  • odontogenic cysts
  • odontogenic tumours
44
Q

What is reimpaction of teeth?

A

Where a previously erupted tooth becomes submerged in the tissues

45
Q

Which tooth is more commonly affected by reimpaction?

A

E’s

46
Q

Tell me more about reimpaction of teeth:

A
  • twice as frequent in mandible
  • cause unknown
  • consequence = deficient development of alveolar process around tooth = root often partially resorbed and ankylosed = difficult to extract
47
Q

What different form errors of the tooth can there be?

A
  • peg shaped lateral
  • invagination/ dens in dente (tooth within a tooth)
  • enamel pearl
  • dilaceration (kink in root due to tooth movement)
  • taurodontism (pulp chamber with greater apico-occlusal height- failure of HERs to invaginate at the correct level)
  • double teeth (fusion/germination/concrescence)
48
Q

What is fusion?

A

union between dentine and/or enamel of 2 or more separate teeth (e.g. b and c)

49
Q

What is germination?

A

partial development of 2 teeth from a single tooth bud followed by incomplete division (e.g. b and b)

50
Q

What is concrescence?

A

Roots of 1 or more teeth united by cementum alone after formation of the crowns

51
Q

What determines the size of teeth and the jaw?

A

Genetics

52
Q

How many teeth do size abnormalities effect?

A

entire dentition or 1-2 teeth (can be symmetrically distributed)

53
Q

What is macrodontia?

A

The teeth look too big for the patient

54
Q

What is microdontia?

A

Teeth look too small for the patient (looks like lots of retained deciduous teeth - interdental spaces)

55
Q

What are the two stages of normal enamel development?

A

Secretory and maturation

56
Q

What is hypoplastic enamel?

A

Ameloblasts fail to produce normal volumes of matrix

57
Q

What is hypo mineralised enamel?

A

Ameloblasts fail to fully calcify previously formed matrix

58
Q

What are the causes of enamel defects (4)?

A
  • Local infection/trauma
  • Irradiation
  • Idiopathic
  • Generalised causes = environmental (e.g. infections or chemotherapy or prolonged labour) or genetic (amelogenesis imperfecta)
59
Q

What are the consequences of congenital syphilis?

A

= hypoplastic changes, incisors small and tapering with notch (hutchinson’s incisors), first molars are dome shaped crowns (moon molars) or nodular cusps (mulberry molars)

60
Q

What is amelogensis imperfecta?

A

Inherited developmental abnormality of enamel = hypoplastoc or hypo mineralised, autosomal dominant or linked, effects both dentitions and characterised by abrasion and attrition of teeth (no increased susceptibility to caries), look yellow (enamel sheared off)

61
Q

What are the different metabolic causes of dentine defects?

A

Rickets (increased interglobular/pre-dentine) ad tetracycline (staining and banding = taken up into dentine within incremental lines)

62
Q

What are the different genetic causes of dentine defects?

A

Dentinogenesis imperfecta, Dentinal dysplasia and regional odontodysplasia

63
Q

What is Type 1 dentinogenesis imperfecta?

A

Associated with osteogenesis imperfecta

64
Q

What is osteogenesis imperfecta?

A
  • Hereditary disease = group of related disorders characterised by generalised osteoporosis
  • Defect in type 1 collagen (bones have narrow poorly formed cortices composed of immature woven bone)
65
Q

What are the clinical features of osteogenesis imperfecta?

A
  • slender bones/mechanically weak
  • deformity/fractures/deafness
  • lax ligaments/thin translucent skin/blue sclera
  • can be associated with dentinogenesis imperfecta
66
Q

What is Type 2 dentinogenesis imperfecta?

A

affects teeth only (including shell teeth = a variant)

67
Q

Tell me more about type 2 dentinogenesis imperfecta:

A

Autosomal dominant, M=F, 1: 8000, affects both deciduous and permanent teeth

68
Q

What are the clinical features of type 2 dentinogenesis imperfecta?

A
  • Enamel looks Opalescent amber (at eruption) -> normal -> translucent (grey/brown.blue)
  • normal enamel, attrition means rapidly lost
69
Q

What are the radiological features of type 2 dentinogenesis imperfecta?

A
  • short blunt roots

- partial/total obliteration of the pulp chamber and root canal by dentine

70
Q

What are the histological features of type 2 dentinogenesis imperfecta?

A
  • Reduced tubules
  • tubular dentine
  • vascular inclusion
  • straight ADJ (shearing of enamel)
71
Q

What are the biochemical features of type 2 dentinogenesis?

A

abnormally high water content and decreased mineral content of dentine = soft

72
Q

What are shell teeth?

A

A variant of type II dentinogenesis imperfecta
= very rare, pulp chamber not obliterated, dentine is thin and forms shell around pulp, pulp contains coarse collagen fibres and no odontoblasts

73
Q

What is dentinal dysplasia Type 1?

A

Rootless tooth (normal crown, root has dysplastic dentine) = due to defect in HERS)

74
Q

What is dentinal dysplasia type 2?

A

coronal dentine dysplasia = primary teeth are amber colour with obliterated pulp chambers

75
Q

What is regional odontodysplasia?

A

Ghost teeth
= uncommon with unknown aetiology
= abnormalities of enamel, pulp, dentine and dental follicle
= usually anterior maxilla and unilateral (one quadrant only)
= delayed eruption, irregular shape, hypoplastic enamel defects

76
Q

What are the different cementum defects?

A

Hypercementosis and hypocementosis

77
Q

What is hypercementosis?

A

Too much cementum = ankylosis = difficult to extract

Caused by: periapical inflammation, mechanical stimulation, functionless/unerupted, pagets

78
Q

What is hypocementosis?

A

Too little cementum = tooth wobbly and fall out (uncommon)

Causes: cleidocranial dysplasia and hypophosphatasia (recessive autosomal)