Clinical Radiology - Developmental Anomalies Flashcards

1
Q

What are the 4 categories of dental anomalies?

A

Eruption/position
Shape/size
Number
Structure

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2
Q

Movement of a tooth from its position of development to its functional location in the mouth

A

Eruption

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3
Q

After the tooth is in full occlusion, slight ___________ continues to compensate for normal attrition and continued __________ growth of the face

A

eruption; vertical

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4
Q

Emergence has not occurred within 12 months of normal range or when 75% of root is formed

A

Delayed eruption

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5
Q

What are the 2 systemic causes of delayed eruption?

A

Endocrine disorders
Syndromes (Gardner, cleidocranial dysplasia, ectodermal dysplasia, Down’s)

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6
Q

What are the 3 local causes of delayed eruption?

A

Physical barrier
Abnormal position
Trauma

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7
Q

Rare non-syndromic eruption disorder where the tooth fails to erupt in the absence of any mechanical obstruction

A

Primary failure of eruption

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8
Q

Disturbance of tooth eruption that results from fusion of cementum or dentin with alveolar bone

A

Ankylosis

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9
Q

Cessation of eruption because of mechanical interference caused by a physical barrier

A

Impaction

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10
Q

Which 2 teeth are most affected by impaction?

A

3rd molars and canines

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11
Q

What word is sometimes used as a synonym for non-erupted (embedded)?

A

Impaction

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12
Q

What’s the ratio for location (labial/palatal) of impacted canines?

A

1/3 labial
2/3 palatal

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13
Q

What are the 2 types of dental anomalies related to position?

A

Orientation (tooth axis)
Location

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14
Q

What are the types of malpositions of teeth?

A

Mesially angulated
Distally angulated
Transverse (buccolingual)
Horizontal
Inverted
Rotated

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15
Q

Tooth develops in ectopic location or does not follow its usual eruption course

A

Ectopic

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16
Q

Where are ectopic teeth most commonly found?

A

Alveolar process

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17
Q

Where are ectopic teeth found in rare cases?

A

Non-dentate regions

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18
Q

Change in order/position between 2 adjacent teeth in the dental arch

A

Transposition

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19
Q

Is transposition found in primary dentition?

A

No

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20
Q

Which 2 teeth most commonly experience transposition?

A

Upper canines and 1st molars

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21
Q

What category does “transposition” and “transmigration” fall under?

A

Ectopic

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22
Q

Displacement of teeth across midline

A

Transmigration

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23
Q

What teeth most commonly experience transmigration?

A

Lower canines

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24
Q

Unassisted migration of teeth within alveolar process mesially, towards midline

A

Physiological drift

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25
Q

Tendency of teeth to move mesially to maintain contact between teeth

A

Physiological drift

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26
Q

Is physiological drift a developmental anomaly?

A

No!

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27
Q

What does physiological drift cause changes in?

A

Occlusal plane

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28
Q

Excessive # of teeth

A

Supernumerary teeth/hyperdontia

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29
Q

Missing teeth (does not include 3rd molars)

A

Agenesis

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30
Q

What are the 3 types of agenesis?

A

Hypodontia (1-5 missing)
Oligodontia (6+ missing
Andodontia (all 32 missing)

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31
Q

Supernumerary teeth are often __________ or _________

A

embedded; unerupted

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32
Q

Supernumerary teeth have variable numbers, size, and locations, and tend to have variable ____________

A

morphology

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33
Q

Supernumerary tooth in the incisor region of the maxilla

A

Mesiodens

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34
Q

Supernumerary tooth in the molar region of the maxilla

A

Paramolars

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35
Q

Supernumerary tooth posterior to the 3rd molars

A

Distomolars (also called 4th molars)

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36
Q

Unusually large

A

Macrodontia

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37
Q

Unusually small

A

Microdontia

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38
Q

Types of dental anomalies in regards to shape of crown

A

Dens invaginatus
Dens evaginatus
Enamel pearl
Fusion
Germination

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39
Q

Types of dental anomalies in regards to shape of root/pulp chamber

A

Concrescence
Supernumerary roots
Taurodontism
Dilaceration

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40
Q

“Tooth within a tooth” - dens in dente

A

Dens invaginatus

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41
Q

Invagination of the enamel surface into the interior aspect of the tooth

A

Dens invaginatus

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42
Q

What is the order for teeth most affected by dens invaginatus?

A

Lateral incisors > central incisors > premolars > canines > molars

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43
Q

What are teeth with dens invaginatus filled with during development? What happens after eruption?

A

Soft tissue; becomes necrotic after eruption

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44
Q

After a tooth with dens invaginatus erupts, there is a potential space for entrapment of food debris and bacteria, making this tooth prone to what? What does this lead to?

A

Caries -> leads to apical periodontitis

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45
Q

Which type of dens invaginatus?

Confined to crown

A

Type I

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46
Q

Which type of dens invaginatus?

Extends below CEJ as blind sac, +/- pulp

A

Type II

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47
Q

Which type of dens invaginatus?

Transverses root, perforates laterally

A

Type IIIa

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48
Q

Which type of dens invaginatus?

Transverses root, perforates apically

A

Type IIIb

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49
Q

Most severe form; anomalous shape

A

Dilated odontoma

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50
Q

Evagination of enamel, causing an additional tubercle or cusp

A

Dens evaginatus

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51
Q

Additional cusp on posterior tooth

A

Leong premolar, occlusal pearl, evaginated odontoma

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52
Q

Which teeth are most commonly associated with dens evaginatus?

A

Mandibular premolars
Maxillary incisors

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53
Q

Name the characteristics of premolars affected by dens evaginatus

A

Central groove or lingual ridge
Usually bilateral
Pulpal extension common (can lead to pulpal pathosis)

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54
Q

Additional cusp on anterior teeth

A

Talon cusp, Eagle’s talon, supernumerary cusp

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55
Q

Which surface is the additional cusp usually found on for anterior teeth?

A

Lingual surface

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56
Q

In dens evaginatus, the extra cusp on anterior teeth extends at least ____ the distance from the CEJ to the incisal edge

A

1/2

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57
Q

Ectopic hemispherical bulging on root surface

A

Enamel pearl

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58
Q

Well defined, small, radiopaque nodule on root surface, usually at furcation

A

Enamel pearl

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59
Q

What is the order for teeth most commonly affected by enamel pearls?

A

Max molars > man molars > premolars and incisors

60
Q

Which teeth are more often affected by enamel pearls: permanent or deciduous?

A

Permanent

61
Q

Adjacent teeth connected with each other

A

Fusion

62
Q

Rare union of 2 adjacent tooth germs during development

A

Fusion

63
Q

In fusion, what parts are usually connected together?

A

Enamel + dentin (rarely just enamel)

64
Q

Which teeth are more often affected by fusion: permanent or deciduous?

A

Both

65
Q

Which teeth are most commonly associated with fusion?

A

Incisors and canines (rare in posterior teeth)

66
Q

Total number of teeth diminished by 1

A

Fusion

67
Q

Partial development of 2 teeth from 1 single tooth germ

A

Gemination

68
Q

Abnormally formed tooth with usually one root canal

A

Gemination

69
Q

Total number of teeth in the arch is normal

A

Gemination

70
Q

What do both fusion and gemination result in?

A

Enlarged, anatomically correct teeth
Bifid crowns w/ separated roots
Bifid crowns w/ one enlarged root (single or double canals)

71
Q

What is complete gemination called? What does it result in?

A

Twinning

Results in increased total # of teeth

72
Q

What may fusion occur with in rare cases? What does it result in?

A

Supernumerary tooth

Results in normal total # of teeth

73
Q

What are the potential complications of fusion and gemination?

A

Tooth malalignment
Spacing
Dental arch symmetry
Susceptible to caries and perio
Poor esthetics
Impaction of adjacent tooth

74
Q

Connection by root cementum alone

A

Concrescence

75
Q

When does concrescence occur?

A

After crowns are formed

76
Q

Which teeth are most commonly associated with concrescence?

A

Maxillary 2nd and 3rd molars

77
Q

What are 2 possible developmental problems with concrescence?

A

Space restriction
Local trauma

78
Q

What is a possible post-inflammatory problem with concrescence?

A

Apical periodontitis followed by partial resolution (large caries w/ pulpal drainage) and cemental repair

79
Q

Abnormal angulation or bend in the root and less frequently, the crown

A

Dilaceration

80
Q

Displacement of crown/root from normal alignment with each other

A

Dilaceration

81
Q

What are the causes for dilaceration?

A

Idiopathic
Local obstruction
Mechanical trauma to primary during development of permanent germ

82
Q

What is the order for teeth most affected by dilaceration?

A

Man molars > max 2nd premolars > man 2nd molars > incisors

83
Q

How common is dilaceration?

A

Common (1%)

84
Q

What are the implications of dilaceration for endo, exo, ortho, and pros?

A

Endo - perforation
Exo - fracture
Ortho - resorption
Pros - stress to abutment

85
Q

What is the order for teeth most affected by supernumerary roots?

A

Molars (especially 3rd) > man premolars & canines

86
Q

Additional (supernumerary) root on a molar specifically

A

Radix entomolaris

87
Q

Increased apico-occlusal height of pulp chamber

A

Taurodontism

88
Q

What does the pulp chamber resemble in taurodontism?

A

Cud-chewing animals (bulls)

89
Q

Taurodontism causes ___________ displacement of the furcation in multi-rooted teeth

A

apical

90
Q

What conditions/syndromes can be associated with taurodontism?

A

Cleft lip/palate
Down syndrome
Ectodermal dysplasia

91
Q

What treatment is implicated in taurodontism?

A

Endo

92
Q

What treatments are implicated in supernumerary roots?

A

Endo and exo

93
Q

What are the degrees for severity in taurodontism?

A

Hypotaurodontism
Mesotaurodontism
Hypertaurodontism

94
Q

Which structure related dental anomalies have to do with enamel (ectoderm)?

A

Turner hypoplasia
MI hypomineralization
Amelogenesis imperfecta

95
Q

Which structure related dental anomalies have to do with dentin (mesoderm)?

A

Dentinogenesis imperfecta
Dentin dysplasia

96
Q

Which structure related dental anomaly has to do with enamel (ectoderm) and dentin (mesoderm)?

A

Regional odontodysplasia

97
Q

What is the make-up of enamel?

A

98% minerals
2% organic matrix + water

98
Q

What is enamel produced by?

A

Ameloblasts

99
Q

What occurs in the secretory stage of enamel?

A

Secretion of matrix proteins

100
Q

What occurs in the maturation stage of enamel?

A

Mineralization

101
Q

What are the factors for developmental defects in enamel?

A

Inherited vs environmental
Systemic vs local
Timing (prenatal, perinatal, postnatal)

102
Q

Name examples of systemic reasons for developmental defects in enamel

A

Metabolic disturbances, infections, chemicals

103
Q

Name examples of local reasons for developmental defects in enamel

A

Infections, trauma, radiation

104
Q

What would you expect if a developmental defect in enamel occurred during the secretory stage?

A

The thickness of enamel would be reduced

105
Q

What would you expect if a developmental defect in enamel occurred during the maturation stage?

A

The quality and mineralization of enamel would be reduced

106
Q

Reduced thickness of enamel presenting as pits, grooves, thin, or missing enamel; affects 1 or more teeth

A

Enamel hypoplasia

107
Q

Results from changes occurring during the stage of matrix formation in enamel (ameloblasts)

A

Enamel hypoplasia

108
Q

What can cause enamel hypoplasia?

A

Stress (nutritional, trauma, infection)
Genetics

109
Q

Localized quantitative enamel defect on permanent teeth caused by trauma or periapical disease of deciduous teeth

A

Turner’s hypoplasia

110
Q

What does the extent of the enamel defect in Turner’s hypoplasia depend on?

A

Severity of infection or trauma

111
Q

What teeth are most commonly affected by Turner’s hypoplasia?

A

Premolars (infection)
Anterior maxillary teeth (trauma)

112
Q

Spectrum of developmental qualitative hypomineralization enamel defects affecting the permanent 1st molars and incisors

A

Molar-incisor (MI) hypomineralization

113
Q

Molar-incisor (MI) hypomineralization has variable severity, meaning what?

A

Can affect 1 to all 4 1st molars + incisors

114
Q

Patients with Molar-incisor (MI) hypomineralization have a higher risk for what?

A

Caries

115
Q

How common is Molar-incisor (MI) hypomineralization?

A

More common than we once thought - highly prevalent across the globe

116
Q

Genetically inherited condition (absence of systemic disorder or known local factors); defective enamel formation and/or calcification

A

Amelogenesis imperfecta

117
Q

Which teeth are more often affected by amelogenesis imperfecta: permanent or deciduous?

A

Both

118
Q

What is the prevalence of amelogenesis imperfecta in the US?

A

1/14,000

119
Q

Describe the genetic inheritance of amelogenesis imperfecta

A

Autosomal, X-linked
Dominant or recessive

120
Q

What is the clinical presentation of amelogenesis imperfecta?

A

Small, discolored teeth
Enamel defects (pits, grooves, prone to wear, caries, breakage)

121
Q

What are the main types of amelogenesis imperfecta?

A

Hypoplastic
Hypomaturation
Hypocalcified
Hypomaturation-hypocalcified

122
Q

What type of amelogenesis imperfecta?

Vertically reduced crown height
Reduced overall enamel thickness
Smooth appearance
Dentin, pulp chambers, roots may appear normal

A

Hypoplastic

123
Q

What type of amelogenesis imperfecta?

Loss of coronal enamel
Rough appearance
Enamel and dentin have a similar density on X-rays

A

Hypocalcified

124
Q

What is dentin produced by?

A

Odontoblasts

125
Q

What is the make-up of dentin?

A

70% minerals
20% organic matrix + water

126
Q

The ECM of dentin shares similar proteins with ________

A

bone

127
Q

Mutations in genes coding for proteins common to both dentin and bone (type 1 collagen) lead to what types of defects?

A

Dentin and skeletal defects

128
Q

T/F: Odontoblasts continue to function throughout life

A

True!

129
Q

Rare hereditary developmental disturbance of dentin

A

Dentinogenesis imperfecta

130
Q

Which teeth are more often affected by dentinogenesis imperfecta: permanent or deciduous?

A

Both

131
Q

Describe the genetic inheritance of dentinogenesis imperfecta

A

Autosomal
Dominant or rescessive

132
Q

What are the clinical features of dentinogenesis imperfecta?

A

Opalescent teeth (amber/blue color)
Wear/enamel fractures
Bulbous crowns
Pulp canal obliteration

133
Q

What are the clinical features of dentinogenesis imperfecta types I and II?

A

Generalized (primary dentition more affected in type I)
Bulbous crowns due to cervical restriction
Pulpal obliteration
Short, thick roots

134
Q

What are the clinical features of dentinogenesis imperfecta type III?

A

More common in primary dentition
Shell teeth - normal thickness of enamel with extremely thin dentin and enlarged pulp chamber

135
Q

What are the types of dentinogenesis imperfecta?

A

Type I - associated with osteogenesis imperfecta
Types II and III - without other inherited disorders

136
Q

Rare genetic condition characterized by normal enamel but atypical dentin with abnormal pulpal morphology

A

Dentin dysplasia

137
Q

Which teeth are more often affected by dentin dysplasia: permanent or deciduous?

A

Both

138
Q

Describe the genetic inheritance of dentin dysplasia

A

Autosomal dominant

139
Q

What are the types of dentin dysplasia?

A

Type I - root
Type II - crown

140
Q

What type of dentin dysplasia?

Short, abnormally shaped root
Merged roots
Complete or partial obliteration of pulp chambers

A

Dentin dysplasia type I

141
Q

What type of dentin dysplasia?

Teeth are normal in color, shape, size
Abnormal pulp chambers - looks like a thistle tube
Leads to pulp stones/partial obliteration

A

Dentin dysplasia type II

142
Q

Rare developmental anomaly of both ectodermal (enamel) and mesodermal (dentin, pulp, cementum) dental components

A

Regional odontodysplasia

143
Q

Which teeth are more often affected by regional odontodysplasia: permanent or deciduous?

A

Both

144
Q

Is regional odontodysplasia localized or systemic?

A

Localized within a segment or quadrant

145
Q

Describe the clinical presentation of regional odontodysplasia

A

Look like “ghost teeth”
Hypoplastic/hypomineralized enamel
Defective layers of enamel + dentin
Enlarged pulp
Unerupted or erupted teeth