hypodontia Flashcards

1
Q

What is hypodontia?

A

Congenital absence of one or more teeth

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2
Q

What is anodontia?

A

Complete absence of teeth

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3
Q

What is severe hypodontia?

A

6 or more congenitally absent teeth

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4
Q

What is the prevalence of hypodontia?

A

6.3% in females
4.6% in males
0.9% in primary dentition - if primary also likely to be permanent
Missing upper laterals in 1-2% of population

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5
Q

What teeth are most affected by hypodontia?

A

Last in a series - 2s, 5s and 8s

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6
Q

What are the 3 types of hypodontia?

A

Non-syndromic
Syndromic
Environmental

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7
Q

Describe non-syndromic hypodontia?

A

Can be familial or sporadic
Mutations in at least 3 genes associated with missing teeth

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8
Q

Describe syndromic hypodontia

A

> 100 craniofacial syndromes associated with hypodontia
eg - Clift lip and palate, anhydrotic ectodermal dysplasia

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9
Q

Describe environmental hypodontia

A

May be caused by trauma, radiotherapy and chemotherapy

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10
Q

How may hypodontia present?

A

Delayed or asymmetric eruption
Retained or infra-occluded primary teeth
Absent primary teeth
Abnormality of tooth form

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11
Q

What is the most important factor in order of eruption?

A

Disorder of sequence

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12
Q

Name 6 associated problems with hypodontia

A

Any 6 from:
- microdontia
- malformation of other teeth
- short root anatomy
- impaction
- delayed formation and/or delayed eruption other teeth
- crowding and malpositioned teeth
- maxillary canine/first premolar transposition
- taurodontism
- enamel hypoplasia
- altered craniofacial growth

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13
Q

What are the potential problems of hypodontia?

A

Spacing
Drifting
Over-eruption
Aesthetic impairment
Functional problems

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14
Q

Where is hypodontia referred?

A

Recognised by GDP
Referred to either specialist orthodontist or dental hospital
Dental hospital will assess and allocate to appropriate hypodontia clinic

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15
Q

What are the steps in tx planning for hypodontia?

A

History
Extra-oral examination
Intra-oral examination - ortho aspect and restorative aspect
Investigations
Problem list
Definitive plan
Retention

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16
Q

What investigations are used for hypodontia?

A

Study models
Planning models with diagnostic wax-ups
Radiographs
Photographs
CBCT

17
Q

What are the options for missing upper lateral incisors?

A

Accept
Restorative alone
Orthodontics alone
Combined orthodontic and restorative treatment

18
Q

What are the options for missing upper lateral incisors if the space is open?

A

Partial dentures
Resin bonded bridge
Implant

19
Q

What are the options for missing upper lateral incisors if the space is closed?

A

Simple closure
Space closure ‘plus’

20
Q

What are the advantages of RBBs for missing upper lateral incisors?

A

Relatively simple
Can do when patient is young
Non-destructive
Can look good
Place on a semi-permanent basis

21
Q

What are the disadvantages of RBBs for missing upper lateral incisors?

A

Failure rate
Appearance sometimes not good
Orthodontic retention needs are high
Aesthetics not predictable
Must place in lateral incisor position, not canine position - higher fail rate due to higher forces eg - lateral excursion

22
Q

What is needed for an implant for replacing missing upper lateral incisors?

A

Growth must have ceased - patient age 21
Need minimum 7mm space
Often need bone graft
Must have root separation for space
Technically very demanding in aesthetics
Significant extra time
Significant cost

23
Q

What is space closure plus?

A

Alterations in tooth shape and size made
Changes in tooth colour made
Alteration in gingival architecture made

24
Q

What are the advantages of space closure plus?

A

No prosthesis so relatively low maintenance
Good aesthetics with appropriate orthodontic and restorative technique
Can be done at any age

25
Q

How is a RBB for a missing upper lateral carried out?

A

Mesial cantilever on canine due to root lengths, crown dimensions and less shine through