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4th yr- CCD2- Ortho > Developmental anomalies in orthodontic > Flashcards

Developmental anomalies in orthodontic Flashcards

1
Q

List the different types of anomalies present in orthodontics

A
  1. Anomalies of tooth number
  2. Anomalies in tooth size and form
  3. Anomalies of tooth eruption
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2
Q

Give examples of anomalies of tooth number

A
  1. Supernumeraries

2. Hypodontia

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3
Q

Define supernumeraries

A

A tooth (or tooth like structure) that is additional to the normal series

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4
Q

What is the incidence percentage of supernumeraries in permanent dentition

A

2-4%

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5
Q

What is the incidence percentage of supernumeraries in primary dentition

A

0.8%

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6
Q

Are supernumeraries more common in men or women

A

Men

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7
Q

Are supernumeraries in the mandible or maxilla more common

A

5 times more likely to have supernumeraries in the maxilla than mandible

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8
Q

How can we classify supernumeraries

A
  1. By form

2. By site

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9
Q

List the different ways we classify supernumeraries by form

A
  1. Supplemental
  2. Conical
  3. Tuberculate
  4. Odontome
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10
Q

What is a supplemental supernumerary tooth

A

An extra tooth of normal ish form

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11
Q

What is a conical supernumerary tooth

A

Generally early forming and peg shaped extra tooth

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12
Q

What is a tuberculate supernumerary tooth

A

generally late forming tooth and is barrel shaped

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13
Q

List the different types of odontome supernumerary

A
  1. Compound

2. Complex

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14
Q

What are compound odontome supernumerary teeth

A

Supernumeraries containing many small serpent tooth like structures

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15
Q

What are complex odontome supernumerary teeth

A

A large mass of disorganised enamel and dentine usually found posteriorly

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16
Q

How can we classify supernumeraries by site

A
  1. Mesiodens
  2. Paramolar / parapremolar
  3. Distodens/Distomolar
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17
Q

Where is a Mesiodens supernumerary found

A

Midline between the central incisors

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18
Q

Where is a Paramolar / parapremolar supernumary found

A

Adjacent to the molars/ premolars

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19
Q

Where is a Distodens/Distomolar supernumerary found

A

Distal to the arch

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20
Q

Name the most common form of supernumerary teeth

A

Conical

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21
Q

Where are conical supernumerary teeth often found

A

Mesiodens that can cause diastema

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22
Q

When do conical supernumerary teeth usually form

A

Root formation starts ahead or with the permanent incisors

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23
Q

How do we manage conical supernumerary teeth

A

They are unlikely to impede eruption and if they aren’t high we can leave them
If they erupt in the palate then we remove them under LA

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24
Q

What shape are conical supernumerary teeth

A

Peg shaped

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25
Q

What shape are tuberculate supernumerary teeth

A

Barrel shaped

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26
Q

Where do tuberculate supernumerary teeth usually form

A

Usually form palatal and they are more likely to impede eruption
They often occur in pairs

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27
Q

How do we manage tuberculate s supernumerary teeth

A

They need to be removed

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28
Q

What other conditions can be associated with supernumerary teeth

A
  1. Cleft lip and palate
  2. Gardners syndrome
  3. Cleidocranial dysostosis
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29
Q

Where do patent with cleft lip usually develop supernumerary teeth

A

Adjacent to the cleft site

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30
Q

What is Gardners syndrome

A

A rare inherited syndrome which causes multiple pre cancerous polyps in the colon

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31
Q

What is Cleidocranial dysostosis also referred to as

A

Cleidocranial dysplasia

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32
Q

Describe Cleidocranial dysostosis

A

Can be inherited or a new mutation on the runnex 2 gene

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33
Q

What does Cleidocranial dysostosis cause

A

The collarbones to be missing

Hyperplastic maxilla

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34
Q

What problems can supernumerary teeth cause

A
  1. Impede eruption of other teeth
  2. cause displacement or rotation of erupted teeth
  3. Produce spacing between erupted teeth
  4. Contribute to crowding if they erupt
  5. Can undergo cystic change
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35
Q

Do s supernumerary teeth usually cause problem

A

Majority of them fail to erupt so no problems just radiographic findings

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36
Q

What is hypodontia

A

The developmental absence of one or more teeth (excluding 8s)

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37
Q

What is the prevalence of hypodontia teeth

A

6.4% But varies amongst populations

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38
Q

List the teeth (in order off most to least) that are usually missing

A

L5
U2
U5
L1

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39
Q

What is the aetiology of hypodontia

A

Genetic aetiology affecting the MSX1, PAX9 or AXIN2 genes

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40
Q

Is hypodontia more common in men or women

A

Women (60% of cases)

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41
Q

How is hypodontia classified

A

Mild Moderate Severe
or
Hypodontia Oligodontia Anodontia

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42
Q

What is mild hypodontia

A

1-2 teeth missing

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43
Q

What is moderate hypodontia

A

3-5 teeth missin

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44
Q

What is severe hypodontia

A

more than 6 teeth missing

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45
Q

What other terms can we use to describe missing teeth

A

Hypodontia
Oligodontia
Anodontia

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46
Q

What is Oligodontia

A

Absence of more than 6 teeth

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47
Q

What is Anodontia

A

Absence of all teeth

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48
Q

List some conditions associated with Hypodontia

A
  1. Cleft lip and palate
  2. Down syndrome
  3. Ectodermal dysplasai
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49
Q

What is ectodermal dysplasia

A

A group of genetic disordered which involve defects of the hair, skin, teeth, nails, mucous membranes and sweat glands

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50
Q

How do we treat Hypodontia patients

A
  1. Open the space and replace missing teeth with prosthetic teeth (denture, bridges or implants)
  2. Can use orthodontics to close the spaces
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51
Q

List anomalies of tooth size and form

A
  1. Microdontia
  2. Macrodontia / Megadontia
  3. Double teeth
  4. Invagination
  5. Accessory cusps
  6. Dilaceration
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52
Q

What is microdontia

A

Teeth which have smaller than average dimension

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53
Q

Which part of the tooth can be affected by microdontia

A

Crown, the root or while tooth

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54
Q

What is the aetiology of microdontia

A

Usually genetic

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55
Q

how common is microdontia

A

Around 2.5% of people have at least one microdont tooth

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56
Q

Which tooth is most commonly affected by microdontia

A

The upper 2s - pegged laterals

one Pegged 2 and one missing

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57
Q

How small must a tooth be to be considered true microdont

A

It must be 2 standard deviations from the average size for that tooth

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58
Q

What treatment options of we have to manage microdontia

A
  1. Accept it
  2. Create space and build the microdont tooth
  3. Extract the microdont tooth and close the space using orthodontic
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59
Q

When do we just accept microdontia

A

Done if microdontia is milk or in a less aesthetically challenging areas

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60
Q

How can we build up a microdont tooth

A
  1. Direct Composite
  2. Lab made veneer
  3. 3/4 crown
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61
Q

What is Macrodontia / Megadontia?

A

Teeth which have larger than average dimensions

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62
Q

Which part of the tooth is affected by Macrodontia / Megadontia

A

Crown , root or whole tooth

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63
Q

What is the aetiology of Macrodontia / Megadontia

A

Usually genetic

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64
Q

How common is Macrodontia / Megadontia

A

Around 1% of people have at least one megadont tooth

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65
Q

Which teeth are most commonly affected by Macrodontia / Megadontia

A

Upper 1s or lower 5s

Often bilateral

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66
Q

How big must a tooth be to be considered true macrodont

A

It must be 2 standard deviations bigger the average size for that tooth

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67
Q

What can Macrodontia / Megadontia sometimes be confused with

A

Double tooth

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68
Q

How can we differentiate Macrodontia / Megadontia from double teeth

A

Macrodontia / Megadontia usually lack coronal nothing and have normal pulpal form

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69
Q

What are the treatment options for Macrodontia / Megadontia

A
  1. Accept and leave it
  2. Extract and reduce space
  3. Extract and close space
  4. camouflage the macrodont to resemble 2 teeth
70
Q

When do we accept Macrodontia / Megadontia

A

If it is a mild case of in a less aesthetically challenging area

71
Q

What is double teeth

A

Fusion of 2 separate tooth farms leading to a reduced number of teeth in the arch

72
Q

What is gemination

A

Developmental separation of a single tooth germ

73
Q

Are double teeth more common in primary or permanent dentition

74
Q

What is the prevalence of double teeth in primary dentition

75
Q

What is the prevalence of double teeth in permanent dentition

76
Q

Are double teeth more common in men or women

A

both equally

77
Q

Describe the appearance of double teeth clinically

A

Can vary from a small notch on a wide crown/root to apparent separate crowns with a shared root

78
Q

What can double teeth be due to

A
  1. Gemination

2. Fusion

79
Q

What is fusion

A

The joining of 2 adjacent tooth germs

80
Q

How can we differentiate between gemination and fusion

A

By counting the number of teeth present clinically and by using radiographs

81
Q

Name a condition related to double teeth

A

Concrescence

82
Q

What is Concrescence

A

Where the cementum of 2 adjacent teeth fuse

83
Q

Which teeth are usually affected by Concrescence

A

6s and 7s or 7s and 8s

84
Q

How can we diagnose Concrescence

A

Using radiographs or CBCT

85
Q

What problems can Concrescence cause

A

Can make extractions difficult

86
Q

How can we treat double teeth

A
  1. If in primary dentition no intervention
  2. If 2 root canals then can surgically divide
  3. Extraction
87
Q

What should we be weary of in primary and permanent double teeth

A

Caries at the interface between the 2 crown segments

88
Q

If we leave a primary double tooth what should we check for

A

That there is a permanent successor

89
Q

What is invagination

A

An enamel lined infolding in the crown of a tooth which can extend into the root

90
Q

What is the prevalence of invagination

A

1-5% of people depending on ethnicity

91
Q

What cause invagination

A

It is caused by an invagination of the enamel epithelium into the dental papilla during development

92
Q

Which teeth are most commonly affected by invagination

A

Upper 2s followed by upper 1s

93
Q

Describe and name a milder form of invagination

A

Dens invaginatus which has a similar appearance to a deep cingulum pit

94
Q

Describe and name a severe form of invagination

A

Dens in dente which forms the invagination starting at the incisor edge and can lead to a grossly abnormal crown and root

95
Q

What problems are associated with invagination

A
  1. High caries risk due to difficulty cleaning

2. Bacterial ingress into the pulp leading to pulpal disease

96
Q

How can we manage invagination

A
  1. Can they to maintain. less severe forms with adhesive restoration
  2. Can attempt RCT
  3. Extraction and closure of space
97
Q

What is an accessory cusp

A

Additional outward projections of enamel and dentine off the body of the tooth

98
Q

How common are accessory cusps

A

fairy common around 10-60% of population

99
Q

Name some accessory cusps

A
  1. Cusp of Carabelli

2. Talon Cusp

100
Q

Where is cusp of Carabelli found

A

On the upper 6

101
Q

Where are talon cusps found

A

On maxillary incurs

102
Q

If a patient has a talon cusp what should we check for

A

Check for cares at the interface of the talon cusp and proper tooth

103
Q

What is Dilaceration

A

An abrupt deviation along the long axis of the crown or root

104
Q

Which tooth is most commonly affected by Dilaceration

A

Upper incisors

105
Q

What can Dilaceration lead to

A

Failure of eruption

106
Q

How can we manage milder cases of Dilaceration

A

Can expose, bond traction and attempt orthodontic alignment

107
Q

How can we manage a more severe cases of Dilaceration

A

Will need to remove the tooth

108
Q

What is the aetiology of Dilaceration

A
  1. Traumatic

2. Developmental

109
Q

How can trauma lead to Dilaceration

A

Due to intrusion of a primary incisor into developing tooth germ

110
Q

How may a traumatic Dilaceration look clinically

A

Generally crown is angled palatally and hypoplasia seen at the site of Dilaceration

111
Q

What does the position of a traumatic Dilaceration on the tooth indicate

A

Corresponds with staff of development at the time of the trauma

112
Q

How can development problems lead to Dilaceration

A

May be due to an obstruction of the eruption path

113
Q

How may a developmental Dilaceration appear clinically

A

Generally crown is angled upwards and labially and no hypoplasia is seen

114
Q

How do we notice a patient has a Dilaceration

A

When the contralateral incisor has erupted and it has been around 6 months and the other hasn’t
Take a radiographs to confirm diagnosis

115
Q

Give examples of anomalies of tooth eruption

A
  1. Delayed eruption
  2. Unerupted teeth
  3. Mechanical failure of eruption / ankylosis
116
Q

When do we investigate delayed eruption

A

If a tooth hasn’t erupted more than 6-12 months after its contralateral

117
Q

Talk through the sequence of eruption in the permanent upper arch

A 
6s (1st molar)
1s (central incisor)
2s (lateral incisor)
4s (1st premolar)
5s (2nd premolar)
3s (Canine)
7s (2nd molar)
8s (wisdom tooth)
118
Q

Talk through the sequence of eruption in the permanent lower arch

A 
6s (1st molar)
1s (central incisor)
2s (lateral incisor)
3s (Canine)
4s (1st premolar)
5s (2nd premolar)
7s (2nd molar)
8s (wisdom tooth)
119
Q

How do we investigate delayed eruption

A

By taking radiographs to check why eruptions delayed

120
Q

What systemic condition can led to delayed eruption

A
  1. Cleidocranial Dysostosis
  2. Down Syndrome
  3. Cleft Lip and Palate
  4. Hereditary Gingival Hyperplasia
121
Q

What local factors can led to delayed eruption

A
  1. Crowding / Supernumeraries
  2. Trauma / Dilaceration
  3. Ectopic Tooth Germ
  4. Early Loss of Primary Teeth
  5. Retention of Primary Teeth
  6. Local Pathology
  7. Transpositions
122
Q

What is transposition

A

The position of 2 teeth swapping

123
Q

Which teeth most commonly undergo transposition

A

The canine and lateral incisor

124
Q

Name the 2 types of transposition

A
  1. Sudo transposition

2. True transposition

125
Q

What is sudo transposition

A

Where just the crowns have swapped positions

126
Q

What is true transposition

A

When the whole tooth (including the root) have swapped positions

127
Q

How can we classify unerutped teeth

A
  1. Ectopic

2. Impacted

128
Q

What is an ectopic tooth

A

One that has erupted in an abnormal place or position

129
Q

What is an impacted tooth

A

When a physical impediment to eruption by another structure such as bone, adjacent teeth or soft tissues has occurred

130
Q

What is the most common reason for an upper 1 not to erupt

A

Dilaceration or obstruction

131
Q

What is the most common reason for an upper or lower 5 not to erupt

A

Lack of space / obstruction

132
Q

What is the most common reason for an upper 6 not to erupt

A

Impaction into Es

133
Q

What is the most common reason for an upper or lower 8s not to erupt

A

lack of space or impaction

134
Q

Are unerupted canines more common in men or women

A

Women (70%)

135
Q

Are unerupted canines more common in men or women

A

Women (70%)

136
Q

What is the aetiology of unerupted upper canines

A

Polygenic multifactorial due to:

  1. Genetic theory
  2. Guidance theory/ local factors
137
Q

List some genetic factors that can lead to unerupted upper canines

A
  1. Family history

2. Associated malformation

138
Q

List some local factors that can lead to unerupted upper canines

A
  1. Missing or absent lateral incisor
  2. Retention of primary canine
  3. Crowding
139
Q

What are the consequences of unerupted upper canines

A
  1. Root resorption
  2. Coronal resorption
  3. Cystic change
140
Q

Describe the root resorption that can occur due to unerupted upper canines

A

Up to 2/3rds of upper 2s have root resorption due to ectopic upper canines
Most root resorption happens before 14

141
Q

How do we monitor and catch unerupted canines early

A

Canine screening

142
Q

Are unerupted upper canines bilateral or unilateral

A

More commonly bilateral

143
Q

How dow screen for canines

A

Majority of normal erupting maxillary canines should be palpable in the buccal sulcus by 10 years old

144
Q

When should we should we start palpating canines

A

Age of 9

caNINE

145
Q

When is eruption of an upper canine considered late in boys

146
Q

When is eruption of an upper canine considered late in girls

147
Q

What should you do if you can’t palpate a canine by age 10

A

Refer to specialist

148
Q

Define ankylosis

A

Isolated condition causing a localised failure of eruption of a single tooth with no other identifiable causes

149
Q

What is ankylosis also known as

A

Mechanical failure of eruption

150
Q

What is primary failure of eruption

A

Are isolated condition causing localised failure of eruption of multiple teeth with no other identifiable causes

151
Q

What is the key difference between primary failure of eruption and mechanical failure of eruption

A

Primary failure is failure of eruption of MULTIPLE teeth

152
Q

Which teeth are most commonly affected by primary failure of eruption

A

Posterior teeth

153
Q

What can primary failure of eruption lead to

A

Lateral open bite

154
Q

How do we manage primary failure of eruption

A

Generally restorative options as tooth won’t respond to orthodontic forces

155
Q

What causes primary failure of eruption

A

Strong genetic component where PTH1R gene is affected

156
Q

List some condition / syndromes commonly associate with dental anomalies

A
  1. Cleft lip and/ or palate
  2. Downs syndrome
  3. Hypohydrotic ectodermal dysplasia
  4. Cleidocrnaial Dysostosis
157
Q

How common is cleft lip and palate in caucasians

A

Seen in 1 in 700 to 1 in 1000 live births

158
Q

How common is cleft lip and palate in asians

A

1 in 500 live births

159
Q

How common is cleft lip and palate in Africans

A

1 in 2500 live births

160
Q

Is cleft lip and palate more common in men or women

161
Q

How common is cleft palate on its own

A

Seen in 1 in 2000 live births

162
Q

Is isolated cleft palate more common in men or women

A

Women (80%)

163
Q

How can cleft lip and or palate be presented

A
  1. Unilateral cleft lip
  2. Bilateral cleft lip
  3. Unilateral cleft lip and palate
  4. Bilateral cleft lip and palate
  5. Isolated cleft palate
164
Q

How common is Down syndrome

A

Seen in 1 in 700 live briths

165
Q

What causes down syndrome

A

Trisomy of chromosome 21

166
Q

What are the key dental findings of Down syndrome

A
  1. Class III malocclusion
  2. Hypodontia
  3. Cleft lip and/or palate
  4. Microdontia
  5. Delayed eruption of secondary dentition
  6. Short roots
167
Q

What is Hypohydrotic ectodermal dysplasia

A

A condition leading to smooth dry skin with sparse hair and partial or total absence of seat glands

168
Q

What are the key dental findings of Hypohydrotic ectodermal dysplasia

A
  1. Class III malocclusion
  2. Anadontia/ Severe Hypodontia
  3. Cleft lip and/or palate
  4. Deformed teeth/ conical crown
  5. Delayed eruption
  6. Xerostomia
169
Q

What is Cleidocrnaial Dysostosis

A

Absence / hypoplastic clavicles

Helmet like skull due to Fontanelles and sutures persisting

170
Q

what is Cleidocrnaial Dysostosis caused by

A

Mutation in CBFA1/RUNX2 gene

171
Q

What are the key dental findings of Cleidocrnaial Dysostosis

A
  1. Class III malocclusion - Mx hypoplasia
  2. Multiple supernumerary teeth
  3. Dentigerous cysts
  4. Retained 1ry teeth
  5. Failure of eruption of secondary teeth

4th yr- CCD2- Ortho (7 decks)

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