5- Aetiology of Malocclusion local and dental factors Flashcards
Lecture Aims:
1. Understand the role of local factors in aetiology of malocclusion and treatment planning
2. Understand how to preserve arch length following loss of teeth by using space maintainers
3. The role of the GDP in identifying patients and referrals.
Malocclusion occurs due to:
Aetiology of malocclusion ; list the dental factors
Soft tissue factors: Fraenum
What can it casue
Midline Diastema
Incidence?
List 6 causes of a midline diastema:
Treatment:
Eruption cyst
What is it?
Treatment:
Local and dental factors
What can jaw fractures, cysts and neoplasms cause?
They can cause all of the three clinical findings
What can you see?
Treatment
what can you see and effects on adjacent structure
Treatment
Trauma
Which dentition can trauma injuries occur?
What does damage to ____ lead to?
- crown
- roots
Effect of trauma depends on (2)
Dental trauma
Trauma to incisor (beneath gum)
Explain 5 effects of this
And treatment
Urgent referral for orthodontic treatment
Upper central incisor - mesially tipped
The higher up tooth is a lateral incisor
Tooth has been traumatised and if it becomes horizontal (left x ray) can polo mint appearance (right x ray)
Identify what you can see
What would you expect on extraction
Treatment
Unerupted incisor- deflected and horizontal as show by x ray on right (pink circles)
When tooth is extracted would expect it to be dilacerated as shown by photograph - Dilacerated = change in position of root
Look out for asymmetric eruption of teeth esp central incisors + Ask about history of trauma
Local dental factors that cause malocclusion (7):
Tooth size - microdontia
Definition
Associated with?
Clinical features
Treatment
Micrdontia = small teeth
Laterals are peg shaped in lower image
Tooth size - Macrodontia
Definition
Clinical features
Treatment
Poor aesthetics
Tooth morphology
List 4 types and their definitions
Tooth morphology - Dens Evaginatus
What is it and where is it commonly found?
List 3 clinical issues:
Treatment
1-
1-
Dens evaginatus, also known as a talon cusp, is an extra cusp on a tooth.
• It occurs in permanent dentition with an incidence of 1-6%, most commonly on:
• 55% of maxillary lateral incisors
• 33% of maxillary central incisors
• It is rare in primary dentition
2-
Presence of a talon cusp can lead to:
• Pulpal horn exposure.
• Occlusal interference or displacement of other teeth.
• Increased risk of infection or the need for root canal treatment (RCT).
Often there is a pit around the extra cusp which can be a sit for caries.
If cusp is large can get displacement of lateral incisor palatally because of occlusion
Have to take care as often have a pulp horn - x ray to assess
Tooth morphology - Dens invaginatus
What is it?
Affects which type of teeth
2 complications
Treatment
1- Infolding of dental epithelium during tooth development
Coronal/ radicular
2- maxillary lateral incisor
3-
1. Infection
2. RCT problematic - complex anatomy pulp
4- referral
Missing teeth - Hypodontia
1- Define anadontia + hypodontia
2- Aetiology + association with which syndromes ?
3- Which dentition affected more?
4- F or M prevalence
5- Which teeth commonly affected?
6- What is classified as severe hypodontia?
7 treatment
Teeth most frequently affected:
• Third molars
• Second premolars
• Upper lateral incisors
Missing teeth - Hypodontia
1- Define anadontia + hypodontia
2- Aetiology + association with which syndromes ?
3- Which dentition affected more?
4- F or M prevalence
5- Which teeth commonly affected?
6- What is classified as severe hypodontia?
7 treatment
Teeth most frequently affected:
• Third molars
• Second premolars
• Upper lateral incisors
Missing teeth
What 3 Clinical Findings occur with missing teeth:
4 factors in planning
Treatment
Infraocclusion shown in the clinical photograph
LIST 6 OPTIONS FOR MISSING TEETH
Supernumerary teeth
1- what are they?
2- 2 types?
3- Aetiology - associated with which 4 conditions?
4- Where are they mostly found?
5- which teeth are common?
6 treatment
Upper photograph - primary dentition - from R TO L - C B A A A B C
Lower photograph - primary dentition - 6 lower incisors
Supernumerary teeth
List 8 types:
Compound and complex should be removed
Supernumerary teeth
List 8 types:
Compound and complex should be removed
Supernumerary teeth - List 9 clinical findings o
Supernumerary teeth
Treatment
4 planning factors
Identify what you can see
Failure of eruption
List all the causes of failure of eruption
Disturbed sequence of eruption
What can lead to a disturbed sequence of eruption and what does this cause
What does effect depend on
Treatment
In this photo lateral incisor are erupting before central incisors
Early loss of primary teeth leads to? (5)
What can you see
What can you see
Infra occlusoin - teeth showing signs of ankylosis
Deciduous teeth below occlusal plane and almost submerged into gum- stopping premolar eruption - shown in green
Disturbed eruption - Early loss of primary dentition
What does loss’s of A, B, C, D and E lead to?
Treatment
Disturbed sequence of eruption - Late loss
What does late loss of primary dentition lead to? (3)
Treatment
Symmetric eruption is normal and should look out for this
Assymetric eruption suggests something wrong
Carious molars
Unplanned loss of molars can lead to: (3)
Look for furcations of 7s to identify the best time to extract carious 6s
Impacted canines
What is their most common position
What are 4 predisposing factors for impacted canines
What is done for impacted canines
3 favourable options for treatment and 2 unfavourable
Transpositions
Difference between true and pseudo transpositions
Aetiology
Which teeth most common
Associated with?
5 factors influencing outcomes
2 treatment options
Commonest exchange is between U4 and 3 OR U3 and 2
Abnormalities in tooth structure - amelogenesis and dentinogenesis
Makes ortho complex
Refer these patients
Problem when debonding brackets
Space maintenance
1- Space maintenance used to?
2- When is it used (3)
3- Why is it used? (3)
Early loss or Assymetric loss are a problem
1 Minimise disturbance in developing occlusion
Space maintainers
List 3 types
Removable - issue with pt compliance
Role of GDP i
