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Y2 Radiography > 9. Dental Anomalies > Flashcards

9. Dental Anomalies Flashcards

1
Q

The 4 types of Amelogenesis Imperfecta are..

A
  1. Hypoplastic type
  2. Hypomaturation type
  3. Hypocalcification type (more common than hypoplastic type)
  4. Hypomaturation with Taurodontism
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2
Q

Which genes mutate in AI?

A
  1. Amelogenin (AMELX)
  2. Enamelin (ENAM)
  3. Enamelysin (MMP20)
  4. Kallikrein (KLK4)
  • no need to be able to regurgitate but must be able to have recollection
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3
Q

How is AI transmitted?

A
  • due to genetic anomalies arising from mutations
  • in autosomal dom or rec manner
  • or X-linked pattern
  • not related to any time/period of enamel development or any clinically demonstrable alteration in other tissues
  • affects all/almost all teeth in both dentitions
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4
Q

Clinical features of hypomaturation type AI:

A

Appearance:
1. Enamel of normal thickness
2. Motteld appearance (spots/smears)
3. Softer than normal, as dense as dentine
=> may easily break away from crown

Colour:
- enamel appears clear/cloudy white/yellow/brown
- can have snow-capped appearance

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5
Q

Radiographic features of hypomaturation type AI:

A

Enamel n dentine of same radiolucency

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6
Q

Clinical features of hypoplastic type AI

A

Appearance:
- reduced thickness => no contact between adj teeth
- may have abnormal surface (rough/smooth, pitted/glossy)
- undersized crowns w roughly square shape
- attrition of low, not fully formed cusp tips => flat occlusal surface of posterior teeth w low/absent cusps

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7
Q

Radiographic features of hypoplastic type AI:

A
  • anterior teeth have ‘picket fence’ appearance
  • normal density BUT pitted enamel appears as localised areas of mottled density

Key stuff: thin layer of enamel, absence of interprox contacts, square shape & ‘picket fence’ appearance

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8
Q

Clinical features of hypocalcification type AI:

A

Appearance of enamel
- normal thickness
- softer than normal, poorly mineralised, less than dentine => fractured away shortly after funciton
- enamel & dentine wear down rapidly => worn down tooth
- explorer point under pressure can penetrate enamel
- crowns of normal size & shape upon eruption

However,
- caries in worn teeth is unusual

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9
Q

Radiographic features of hypocalcification type AI:

A
  • enamel more radiolucent than dentine
  • w advanced attrition/abrasion, obliteration of pulp chambers may complicate recognition of image

Note: reduced radioopacity of enamel & abrasion of crowns

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10
Q

How is DI inherited?

A
  • autosomal dominant
  • equal freq in both sexes
  • affects both dentitions
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11
Q

What are the types of DI?

A

Type I
- associated w osteogenesis imperfecta
- mutation of genes involved in collagen synthesis

Type II
- similar to type I but only affects dentine, no skeletal defects
- mutation of genes DSP & DSPP

Type III
- mutation of genes DSP & DSPP

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12
Q

Which genes are mutated in type I DI?

A
  1. Collagen type I, alpha 1 (COL1A1)
  2. Collagen type I, alpha 2 (COL1A2)
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13
Q

What are the genes mutated in type II & III DI?

A
  1. Dentin sialoprotein (DSP)
  2. Dentin sialophosphoprotein (DSPP)
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14
Q

Clinical features of DI:

A
  • enamel fractures easily => crowns wear rapidly => exposed dentine stained dark brown/black
  • may observe anterior open bite (AOB)

Tooth colour:
- high degree of amber-like translucency
- variable colour, yellow to blue-grey (changes when observed under transmitted/reflected light

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15
Q

Radiographic features of DI:

A
  1. Crowns normal in size
  2. Bulbous appearance of crown, due to constriction at cervical portion
  3. Roots short & slender
  4. Pulp chambers:
    - appear large early in development
    - partial/complete obliteration by deposition of dentine => root canals absent/threadlike
  5. Microscopic communicationi btw residual pulp & oral cavity => areas of rarefying osteitis, in seemingly sound teeth & w/o pulp involvement (but more freq in DD)
  6. Normal bone architexture in max & mand

TLDR: bulbous crowns, constriction at CEJ, short roots, decreased size of pulp chamber & root canals

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16
Q

Type I DI patients display.. (systemically)

A

Due to osteogenesis imperfecta
1. Blue sclera
2. Skeletal deformaties
3. Workman bones (bowing of legs)
4. Progressive osteopenia (loss of bone mineral density)

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17
Q

How is DD transmitted?

A
  • autosomal dominant
  • less frequent than DI
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18
Q

Clinical features of type I (radicular) DD:

A
  • normal shape & colour in both dentitions
  • occasional slight bluish brown transparency
  • teeth misaligned in arch, drifting/spontaneous exfoliation w little/no trauma
19
Q

Radiographic features of type I (radicular) DD:

A

TLDR: short roots, obliterated pulp chambers & root canals (half-moon shaped chambers), PA rarefying osteitis

  • roots short/abnormally shaped/absent
    -> Molar roots present in shallow “W” shape
    -> primary dentition: thin spicules
  • pulp chambers & root canals COMPLETELY obliterated B4 eruption
  • microscopic commuincations btw residual pulp & oral cavity => areas of rarefying osteitis, seen w non-carious teeth (more freq in DD than in DI)

** the only type of AI, DI & DD that we need to be able to via radiograph!!

20
Q

Difference between hypodontia and oligodontia.

A

Hypodontia: missing less than 6 teeth
Oligodontia: missing more than 6 teeth

21
Q

Which teeth are commonly missing in hypodontia cases?

A

More common in permanent dentition
- wisdom teeth
- maxillary laterals
- mandibular 2nd premolars
- mandibular central incisors

  • rmb theres a rs between missing teeth and microdonts (laterals and wisdom commonly)
22
Q

What are mesiodens?

A
  • extra tooth located between 2 central incisors
23
Q

Common cases of hyperdontia:

A
  • mesiodens
  • behind wisdom tooth e.g. #19
  • mandibular premolar region
24
Q

Microdontia occurs most commonly in..

A
  • maxillary laterals => peg shaped deformity
  • maxillary wisdoms => max 3M microdontia
25
Q

Microdontia is related to conditions such as..

A
  • down’s syndrome
  • dwarfism
  • congenital heart disease
  • progeria
26
Q

What is concrescence?

A

Roots of 2 or more developed teeth fused by cementum

27
Q

Concrescence is most common in..

A
  • maxillary molars
  • esp wisdom & supernumerary teeth
28
Q

Clinical significance of concrescence.

A
  • can do RCT
  • difficult to extract, extraction of 1 tooth may result in unintended removal of other
  • affected teeth may fail to erupt/erupt incompletely
29
Q

Difference between fusion and gemination.

A

Fusion: 2 teeth fuse into one, by dentine
- results in fewer teeth in arch

Gemination: division of single tooth bud
- results in invagination of the crown w partial/complete division through the crown & root (‘more teeth’)

30
Q

What is taurodontism?

A

Tooth w elongated body, short roots
- pulp chamber extends from normal position in crown throughout length of body => apically positioned pulpal floor
- more common in molars
- associated w trisomy 21 syndrome

(Not clinically recognisable)

31
Q

What is ankylosis of tooth?

A
  • pathological fusion btn alveolar bone and tooth cementum
32
Q

What is dilaceration?

A
  • disturbance in tooth formation producing sharp bend/curve in tooth crown/root
  • cause: trauma to primary predecessor, while root of permanent successor developing
33
Q

Dilacerations are most common in..

A

Maxillary premolars

34
Q

What is dens invaginatus?

A

Invagination of enamel surface at cingulum area (small pit btw cingulum & lingual surface of incisor)

35
Q

What is dens evaginatus?

A

Outpouching of enamel
- also known as leong’s premolar

36
Q

Difference btw talon cusp and dens evaginatus?

A

Talon cusp: hyperplasia of cingulum of max/mand incisor => extra cusp

Dens evaginatus is more on occlusal surfaces

37
Q

What are enamel pearls/ectopic enamel.

A
  • enamel structures that can be found on the roots of deciduous & permanent teeth
38
Q

What is the origin of enamel pearls?

A
  • formed by hertwig’s epithelial root sheath b4 epithelium loses its enamel forming potential
39
Q

What are the tooth conditions that can arise from syphilis?

A

Hutchinson’s incisor & Mulberry molar
- hypoplasia involving permanent incisors & 1st molars

40
Q

Appearance of hutchinson’s incisors

A
  • screwdriver shaped crowns, mesial & distal surfaces taper from mid-crown to incisal edge
    => edge is less wide than cervical area
  • incisal edge frequently notched
41
Q

Appearance of mulberry molars (1st molar)

A
  • crowns smaller in size
  • cusps smaller size & poorly formed
  • constricted occlusal 1/3 of crown => occlusal surface less wide than cervical area
  • enamel over occlusal surface hypoplastic, unevenly formed in irregular globules
42
Q

What is turners hypoplasia?

A
  • enamel defect in the permanent teeth caused by periapical inflammatory disease in the overlying primary tooth
  • ameloblasts affected
43
Q

Which teeth are most susceptible to turner’s hypoplasia?

A

Mandibular PMs
- primary molars most susceptible to caries & in close proximity of developing PMs

44
Q

Severity of turner’s hypoplasia depends on..

A
  1. Severity of infection/mechanical trauma
  2. Stage of development of permanent tooth

Y2 Radiography (10 decks)

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