Developmental anomalies in orthodontic Flashcards
1
Q
List the different types of anomalies present in orthodontics
A
- Anomalies of tooth number
- Anomalies in tooth size and form
- Anomalies of tooth eruption
2
Q
Give examples of anomalies of tooth number
A
- Supernumeraries
2. Hypodontia
3
Q
Define supernumeraries
A
A tooth (or tooth like structure) that is additional to the normal series
4
Q
What is the incidence percentage of supernumeraries in permanent dentition
A
2-4%
5
Q
What is the incidence percentage of supernumeraries in primary dentition
A
0.8%
6
Q
Are supernumeraries more common in men or women
A
Men
7
Q
Are supernumeraries in the mandible or maxilla more common
A
5 times more likely to have supernumeraries in the maxilla than mandible
8
Q
How can we classify supernumeraries
A
- By form
2. By site
9
Q
List the different ways we classify supernumeraries by form
A
- Supplemental
- Conical
- Tuberculate
- Odontome
10
Q
What is a supplemental supernumerary tooth
A
An extra tooth of normal ish form
11
Q
What is a conical supernumerary tooth
A
Generally early forming and peg shaped extra tooth
12
Q
What is a tuberculate supernumerary tooth
A
generally late forming tooth and is barrel shaped
13
Q
List the different types of odontome supernumerary
A
- Compound
2. Complex
14
Q
What are compound odontome supernumerary teeth
A
Supernumeraries containing many small serpent tooth like structures
15
Q
What are complex odontome supernumerary teeth
A
A large mass of disorganised enamel and dentine usually found posteriorly
16
Q
How can we classify supernumeraries by site
A
- Mesiodens
- Paramolar / parapremolar
- Distodens/Distomolar
17
Q
Where is a Mesiodens supernumerary found
A
Midline between the central incisors
18
Q
Where is a Paramolar / parapremolar supernumary found
A
Adjacent to the molars/ premolars
19
Q
Where is a Distodens/Distomolar supernumerary found
A
Distal to the arch
20
Q
Name the most common form of supernumerary teeth
A
Conical
21
Q
Where are conical supernumerary teeth often found
A
Mesiodens that can cause diastema
22
Q
When do conical supernumerary teeth usually form
A
Root formation starts ahead or with the permanent incisors
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
24
Q
What shape are conical supernumerary teeth
A
Peg shaped
25
What shape are tuberculate supernumerary teeth
Barrel shaped
26
Where do tuberculate supernumerary teeth usually form
Usually form palatal and they are more likely to impede eruption
They often occur in pairs
27
How do we manage tuberculate s supernumerary teeth
They need to be removed
28
What other conditions can be associated with supernumerary teeth
1. Cleft lip and palate
2. Gardners syndrome
3. Cleidocranial dysostosis
29
Where do patent with cleft lip usually develop supernumerary teeth
Adjacent to the cleft site
30
What is Gardners syndrome
A rare inherited syndrome which causes multiple pre cancerous polyps in the colon
31
What is Cleidocranial dysostosis also referred to as
Cleidocranial dysplasia
32
Describe Cleidocranial dysostosis
Can be inherited or a new mutation on the runnex 2 gene
33
What does Cleidocranial dysostosis cause
The collarbones to be missing
| Hyperplastic maxilla
34
What problems can supernumerary teeth cause
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
35
Do s supernumerary teeth usually cause problem
Majority of them fail to erupt so no problems just radiographic findings
36
What is hypodontia
The developmental absence of one or more teeth (excluding 8s)
37
What is the prevalence of hypodontia teeth
6.4% But varies amongst populations
38
List the teeth (in order off most to least) that are usually missing
L5
U2
U5
L1
39
What is the aetiology of hypodontia
Genetic aetiology affecting the MSX1, PAX9 or AXIN2 genes
40
Is hypodontia more common in men or women
Women (60% of cases)
41
How is hypodontia classified
Mild Moderate Severe
or
Hypodontia Oligodontia Anodontia
42
What is mild hypodontia
1-2 teeth missing
43
What is moderate hypodontia
3-5 teeth missin
44
What is severe hypodontia
more than 6 teeth missing
45
What other terms can we use to describe missing teeth
Hypodontia
Oligodontia
Anodontia
46
What is Oligodontia
Absence of more than 6 teeth
47
What is Anodontia
Absence of all teeth
48
List some conditions associated with Hypodontia
1. Cleft lip and palate
2. Down syndrome
3. Ectodermal dysplasai
49
What is ectodermal dysplasia
A group of genetic disordered which involve defects of the hair, skin, teeth, nails, mucous membranes and sweat glands
50
How do we treat Hypodontia patients
1. Open the space and replace missing teeth with prosthetic teeth (denture, bridges or implants)
2. Can use orthodontics to close the spaces
51
List anomalies of tooth size and form
1. Microdontia
2. Macrodontia / Megadontia
3. Double teeth
4. Invagination
5. Accessory cusps
6. Dilaceration
52
What is microdontia
Teeth which have smaller than average dimension
53
Which part of the tooth can be affected by microdontia
Crown, the root or while tooth
54
What is the aetiology of microdontia
Usually genetic
55
how common is microdontia
Around 2.5% of people have at least one microdont tooth
56
Which tooth is most commonly affected by microdontia
The upper 2s - pegged laterals
| one Pegged 2 and one missing
57
How small must a tooth be to be considered true microdont
It must be 2 standard deviations from the average size for that tooth
58
What treatment options of we have to manage microdontia
1. Accept it
2. Create space and build the microdont tooth
3. Extract the microdont tooth and close the space using orthodontic
59
When do we just accept microdontia
Done if microdontia is milk or in a less aesthetically challenging areas
60
How can we build up a microdont tooth
1. Direct Composite
2. Lab made veneer
3. 3/4 crown
61
What is Macrodontia / Megadontia?
Teeth which have larger than average dimensions
62
Which part of the tooth is affected by Macrodontia / Megadontia
Crown , root or whole tooth
63
What is the aetiology of Macrodontia / Megadontia
Usually genetic
64
How common is Macrodontia / Megadontia
Around 1% of people have at least one megadont tooth
65
Which teeth are most commonly affected by Macrodontia / Megadontia
Upper 1s or lower 5s
| Often bilateral
66
How big must a tooth be to be considered true macrodont
It must be 2 standard deviations bigger the average size for that tooth
67
What can Macrodontia / Megadontia sometimes be confused with
Double tooth
68
How can we differentiate Macrodontia / Megadontia from double teeth
Macrodontia / Megadontia usually lack coronal nothing and have normal pulpal form
69
What are the treatment options for Macrodontia / Megadontia
1. Accept and leave it
2. Extract and reduce space
3. Extract and close space
4. camouflage the macrodont to resemble 2 teeth
70
When do we accept Macrodontia / Megadontia
If it is a mild case of in a less aesthetically challenging area
71
What is double teeth
Fusion of 2 separate tooth farms leading to a reduced number of teeth in the arch
72
What is gemination
Developmental separation of a single tooth germ
73
Are double teeth more common in primary or permanent dentition
Primary
74
What is the prevalence of double teeth in primary dentition
0.5-1.6%
75
What is the prevalence of double teeth in permanent dentition
0.1-0.2%
76
Are double teeth more common in men or women
both equally
77
Describe the appearance of double teeth clinically
Can vary from a small notch on a wide crown/root to apparent separate crowns with a shared root
78
What can double teeth be due to
1. Gemination
| 2. Fusion
79
What is fusion
The joining of 2 adjacent tooth germs
80
How can we differentiate between gemination and fusion
By counting the number of teeth present clinically and by using radiographs
81
Name a condition related to double teeth
Concrescence
82
What is Concrescence
Where the cementum of 2 adjacent teeth fuse
83
Which teeth are usually affected by Concrescence
6s and 7s or 7s and 8s
84
How can we diagnose Concrescence
Using radiographs or CBCT
85
What problems can Concrescence cause
Can make extractions difficult
86
How can we treat double teeth
1. If in primary dentition no intervention
2. If 2 root canals then can surgically divide
3. Extraction
87
What should we be weary of in primary and permanent double teeth
Caries at the interface between the 2 crown segments
88
If we leave a primary double tooth what should we check for
That there is a permanent successor
89
What is invagination
An enamel lined infolding in the crown of a tooth which can extend into the root
90
What is the prevalence of invagination
1-5% of people depending on ethnicity
91
What cause invagination
It is caused by an invagination of the enamel epithelium into the dental papilla during development
92
Which teeth are most commonly affected by invagination
Upper 2s followed by upper 1s
93
Describe and name a milder form of invagination
Dens invaginatus which has a similar appearance to a deep cingulum pit
94
Describe and name a severe form of invagination
Dens in dente which forms the invagination starting at the incisor edge and can lead to a grossly abnormal crown and root
95
What problems are associated with invagination
1. High caries risk due to difficulty cleaning
| 2. Bacterial ingress into the pulp leading to pulpal disease
96
How can we manage invagination
1. Can they to maintain. less severe forms with adhesive restoration
2. Can attempt RCT
3. Extraction and closure of space
97
What is an accessory cusp
Additional outward projections of enamel and dentine off the body of the tooth
98
How common are accessory cusps
fairy common around 10-60% of population
99
Name some accessory cusps
1. Cusp of Carabelli
| 2. Talon Cusp
100
Where is cusp of Carabelli found
On the upper 6
101
Where are talon cusps found
On maxillary incurs
102
If a patient has a talon cusp what should we check for
Check for cares at the interface of the talon cusp and proper tooth
103
What is Dilaceration
An abrupt deviation along the long axis of the crown or root
104
Which tooth is most commonly affected by Dilaceration
Upper incisors
105
What can Dilaceration lead to
Failure of eruption
106
How can we manage milder cases of Dilaceration
Can expose, bond traction and attempt orthodontic alignment
107
How can we manage a more severe cases of Dilaceration
Will need to remove the tooth
108
What is the aetiology of Dilaceration
1. Traumatic
| 2. Developmental
109
How can trauma lead to Dilaceration
Due to intrusion of a primary incisor into developing tooth germ
110
How may a traumatic Dilaceration look clinically
Generally crown is angled palatally and hypoplasia seen at the site of Dilaceration
111
What does the position of a traumatic Dilaceration on the tooth indicate
Corresponds with staff of development at the time of the trauma
112
How can development problems lead to Dilaceration
May be due to an obstruction of the eruption path
113
How may a developmental Dilaceration appear clinically
Generally crown is angled upwards and labially and no hypoplasia is seen
114
How do we notice a patient has a Dilaceration
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
Give examples of anomalies of tooth eruption
1. Delayed eruption
2. Unerupted teeth
3. Mechanical failure of eruption / ankylosis
116
When do we investigate delayed eruption
If a tooth hasn't erupted more than 6-12 months after its contralateral
117
Talk through the sequence of eruption in the permanent upper arch
```
6s (1st molar)
1s (central incisor)
2s (lateral incisor)
4s (1st premolar)
5s (2nd premolar)
3s (Canine)
7s (2nd molar)
8s (wisdom tooth)
```
118
Talk through the sequence of eruption in the permanent lower arch
```
6s (1st molar)
1s (central incisor)
2s (lateral incisor)
3s (Canine)
4s (1st premolar)
5s (2nd premolar)
7s (2nd molar)
8s (wisdom tooth)
```
119
How do we investigate delayed eruption
By taking radiographs to check why eruptions delayed
120
What systemic condition can led to delayed eruption
1. Cleidocranial Dysostosis
2. Down Syndrome
3. Cleft Lip and Palate
4. Hereditary Gingival Hyperplasia
121
What local factors can led to delayed eruption
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
What is transposition
The position of 2 teeth swapping
123
Which teeth most commonly undergo transposition
The canine and lateral incisor
124
Name the 2 types of transposition
1. Sudo transposition
| 2. True transposition
125
What is sudo transposition
Where just the crowns have swapped positions
126
What is true transposition
When the whole tooth (including the root) have swapped positions
127
How can we classify unerutped teeth
1. Ectopic
| 2. Impacted
128
What is an ectopic tooth
One that has erupted in an abnormal place or position
129
What is an impacted tooth
When a physical impediment to eruption by another structure such as bone, adjacent teeth or soft tissues has occurred
130
What is the most common reason for an upper 1 not to erupt
Dilaceration or obstruction
131
What is the most common reason for an upper or lower 5 not to erupt
Lack of space / obstruction
132
What is the most common reason for an upper 6 not to erupt
Impaction into Es
133
What is the most common reason for an upper or lower 8s not to erupt
lack of space or impaction
134
Are unerupted canines more common in men or women
Women (70%)
135
Are unerupted canines more common in men or women
Women (70%)
136
What is the aetiology of unerupted upper canines
Polygenic multifactorial due to:
1. Genetic theory
2. Guidance theory/ local factors
137
List some genetic factors that can lead to unerupted upper canines
1. Family history
| 2. Associated malformation
138
List some local factors that can lead to unerupted upper canines
1. Missing or absent lateral incisor
2. Retention of primary canine
3. Crowding
139
What are the consequences of unerupted upper canines
1. Root resorption
2. Coronal resorption
3. Cystic change
140
Describe the root resorption that can occur due to unerupted upper canines
Up to 2/3rds of upper 2s have root resorption due to ectopic upper canines
Most root resorption happens before 14
141
How do we monitor and catch unerupted canines early
Canine screening
142
Are unerupted upper canines bilateral or unilateral
More commonly bilateral
143
How dow screen for canines
Majority of normal erupting maxillary canines should be palpable in the buccal sulcus by 10 years old
144
When should we should we start palpating canines
Age of 9
| caNINE
145
When is eruption of an upper canine considered late in boys
13 years
146
When is eruption of an upper canine considered late in girls
12 years
147
What should you do if you can't palpate a canine by age 10
Refer to specialist
148
Define ankylosis
Isolated condition causing a localised failure of eruption of a single tooth with no other identifiable causes
149
What is ankylosis also known as
Mechanical failure of eruption
150
What is primary failure of eruption
Are isolated condition causing localised failure of eruption of multiple teeth with no other identifiable causes
151
What is the key difference between primary failure of eruption and mechanical failure of eruption
Primary failure is failure of eruption of MULTIPLE teeth
152
Which teeth are most commonly affected by primary failure of eruption
Posterior teeth
153
What can primary failure of eruption lead to
Lateral open bite
154
How do we manage primary failure of eruption
Generally restorative options as tooth won't respond to orthodontic forces
155
What causes primary failure of eruption
Strong genetic component where PTH1R gene is affected
156
List some condition / syndromes commonly associate with dental anomalies
1. Cleft lip and/ or palate
2. Downs syndrome
3. Hypohydrotic ectodermal dysplasia
4. Cleidocrnaial Dysostosis
157
How common is cleft lip and palate in caucasians
Seen in 1 in 700 to 1 in 1000 live births
158
How common is cleft lip and palate in asians
1 in 500 live births
159
How common is cleft lip and palate in Africans
1 in 2500 live births
160
Is cleft lip and palate more common in men or women
Men (66%)
161
How common is cleft palate on its own
Seen in 1 in 2000 live births
162
Is isolated cleft palate more common in men or women
Women (80%)
163
How can cleft lip and or palate be presented
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
How common is Down syndrome
Seen in 1 in 700 live briths
165
What causes down syndrome
Trisomy of chromosome 21
166
What are the key dental findings of Down syndrome
1. Class III malocclusion
2. Hypodontia
3. Cleft lip and/or palate
4. Microdontia
5. Delayed eruption of secondary dentition
6. Short roots
167
What is Hypohydrotic ectodermal dysplasia
A condition leading to smooth dry skin with sparse hair and partial or total absence of seat glands
168
What are the key dental findings of Hypohydrotic ectodermal dysplasia
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
What is Cleidocrnaial Dysostosis
Absence / hypoplastic clavicles
| Helmet like skull due to Fontanelles and sutures persisting
170
what is Cleidocrnaial Dysostosis caused by
Mutation in CBFA1/RUNX2 gene
171
What are the key dental findings of Cleidocrnaial Dysostosis
1. Class III malocclusion - Mx hypoplasia
2. Multiple supernumerary teeth
3. Dentigerous cysts
4. Retained 1ry teeth
5. Failure of eruption of secondary teeth
