Developmental anomalies in orthodontic Flashcards
List the different types of anomalies present in orthodontics
- Anomalies of tooth number
- Anomalies in tooth size and form
- Anomalies of tooth eruption
Give examples of anomalies of tooth number
- Supernumeraries
2. Hypodontia
Define supernumeraries
A tooth (or tooth like structure) that is additional to the normal series
What is the incidence percentage of supernumeraries in permanent dentition
2-4%
What is the incidence percentage of supernumeraries in primary dentition
0.8%
Are supernumeraries more common in men or women
Men
Are supernumeraries in the mandible or maxilla more common
5 times more likely to have supernumeraries in the maxilla than mandible
How can we classify supernumeraries
- By form
2. By site
List the different ways we classify supernumeraries by form
- Supplemental
- Conical
- Tuberculate
- Odontome
What is a supplemental supernumerary tooth
An extra tooth of normal ish form
What is a conical supernumerary tooth
Generally early forming and peg shaped extra tooth
What is a tuberculate supernumerary tooth
generally late forming tooth and is barrel shaped
List the different types of odontome supernumerary
- Compound
2. Complex
What are compound odontome supernumerary teeth
Supernumeraries containing many small serpent tooth like structures
What are complex odontome supernumerary teeth
A large mass of disorganised enamel and dentine usually found posteriorly
How can we classify supernumeraries by site
- Mesiodens
- Paramolar / parapremolar
- Distodens/Distomolar
Where is a Mesiodens supernumerary found
Midline between the central incisors
Where is a Paramolar / parapremolar supernumary found
Adjacent to the molars/ premolars
Where is a Distodens/Distomolar supernumerary found
Distal to the arch
Name the most common form of supernumerary teeth
Conical
Where are conical supernumerary teeth often found
Mesiodens that can cause diastema
When do conical supernumerary teeth usually form
Root formation starts ahead or with the permanent incisors
How do we manage conical supernumerary teeth
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
What shape are conical supernumerary teeth
Peg shaped
What shape are tuberculate supernumerary teeth
Barrel shaped
Where do tuberculate supernumerary teeth usually form
Usually form palatal and they are more likely to impede eruption
They often occur in pairs
How do we manage tuberculate s supernumerary teeth
They need to be removed
What other conditions can be associated with supernumerary teeth
- Cleft lip and palate
- Gardners syndrome
- Cleidocranial dysostosis
Where do patent with cleft lip usually develop supernumerary teeth
Adjacent to the cleft site
What is Gardners syndrome
A rare inherited syndrome which causes multiple pre cancerous polyps in the colon
What is Cleidocranial dysostosis also referred to as
Cleidocranial dysplasia
Describe Cleidocranial dysostosis
Can be inherited or a new mutation on the runnex 2 gene
What does Cleidocranial dysostosis cause
The collarbones to be missing
Hyperplastic maxilla
What problems can supernumerary teeth cause
- Impede eruption of other teeth
- cause displacement or rotation of erupted teeth
- Produce spacing between erupted teeth
- Contribute to crowding if they erupt
- Can undergo cystic change
Do s supernumerary teeth usually cause problem
Majority of them fail to erupt so no problems just radiographic findings
What is hypodontia
The developmental absence of one or more teeth (excluding 8s)
What is the prevalence of hypodontia teeth
6.4% But varies amongst populations
List the teeth (in order off most to least) that are usually missing
L5
U2
U5
L1
What is the aetiology of hypodontia
Genetic aetiology affecting the MSX1, PAX9 or AXIN2 genes
Is hypodontia more common in men or women
Women (60% of cases)
How is hypodontia classified
Mild Moderate Severe
or
Hypodontia Oligodontia Anodontia
What is mild hypodontia
1-2 teeth missing
What is moderate hypodontia
3-5 teeth missin
What is severe hypodontia
more than 6 teeth missing
What other terms can we use to describe missing teeth
Hypodontia
Oligodontia
Anodontia
What is Oligodontia
Absence of more than 6 teeth
What is Anodontia
Absence of all teeth
List some conditions associated with Hypodontia
- Cleft lip and palate
- Down syndrome
- Ectodermal dysplasai
What is ectodermal dysplasia
A group of genetic disordered which involve defects of the hair, skin, teeth, nails, mucous membranes and sweat glands
How do we treat Hypodontia patients
- Open the space and replace missing teeth with prosthetic teeth (denture, bridges or implants)
- Can use orthodontics to close the spaces
List anomalies of tooth size and form
- Microdontia
- Macrodontia / Megadontia
- Double teeth
- Invagination
- Accessory cusps
- Dilaceration
What is microdontia
Teeth which have smaller than average dimension
Which part of the tooth can be affected by microdontia
Crown, the root or while tooth
What is the aetiology of microdontia
Usually genetic
how common is microdontia
Around 2.5% of people have at least one microdont tooth
Which tooth is most commonly affected by microdontia
The upper 2s - pegged laterals
one Pegged 2 and one missing
How small must a tooth be to be considered true microdont
It must be 2 standard deviations from the average size for that tooth
What treatment options of we have to manage microdontia
- Accept it
- Create space and build the microdont tooth
- Extract the microdont tooth and close the space using orthodontic
When do we just accept microdontia
Done if microdontia is milk or in a less aesthetically challenging areas
How can we build up a microdont tooth
- Direct Composite
- Lab made veneer
- 3/4 crown
What is Macrodontia / Megadontia?
Teeth which have larger than average dimensions
Which part of the tooth is affected by Macrodontia / Megadontia
Crown , root or whole tooth
What is the aetiology of Macrodontia / Megadontia
Usually genetic
How common is Macrodontia / Megadontia
Around 1% of people have at least one megadont tooth
Which teeth are most commonly affected by Macrodontia / Megadontia
Upper 1s or lower 5s
Often bilateral
How big must a tooth be to be considered true macrodont
It must be 2 standard deviations bigger the average size for that tooth
What can Macrodontia / Megadontia sometimes be confused with
Double tooth
How can we differentiate Macrodontia / Megadontia from double teeth
Macrodontia / Megadontia usually lack coronal nothing and have normal pulpal form