hypodontia Flashcards
What is hypodontia?
Congenital absence of one or more teeth
What is anodontia?
Complete absence of teeth
What is severe hypodontia?
6 or more congenitally absent teeth
What is the prevalence of hypodontia?
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
What teeth are most affected by hypodontia?
Last in a series - 2s, 5s and 8s
What are the 3 types of hypodontia?
Non-syndromic
Syndromic
Environmental
Describe non-syndromic hypodontia?
Can be familial or sporadic
Mutations in at least 3 genes associated with missing teeth
Describe syndromic hypodontia
> 100 craniofacial syndromes associated with hypodontia
eg - Clift lip and palate, anhydrotic ectodermal dysplasia
Describe environmental hypodontia
May be caused by trauma, radiotherapy and chemotherapy
How may hypodontia present?
Delayed or asymmetric eruption
Retained or infra-occluded primary teeth
Absent primary teeth
Abnormality of tooth form
What is the most important factor in order of eruption?
Disorder of sequence
Name 6 associated problems with hypodontia
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
What are the potential problems of hypodontia?
Spacing
Drifting
Over-eruption
Aesthetic impairment
Functional problems
Where is hypodontia referred?
Recognised by GDP
Referred to either specialist orthodontist or dental hospital
Dental hospital will assess and allocate to appropriate hypodontia clinic
What are the steps in tx planning for hypodontia?
History
Extra-oral examination
Intra-oral examination - ortho aspect and restorative aspect
Investigations
Problem list
Definitive plan
Retention
What investigations are used for hypodontia?
Study models
Planning models with diagnostic wax-ups
Radiographs
Photographs
CBCT
What are the options for missing upper lateral incisors?
Accept
Restorative alone
Orthodontics alone
Combined orthodontic and restorative treatment
What are the options for missing upper lateral incisors if the space is open?
Partial dentures
Resin bonded bridge
Implant
What are the options for missing upper lateral incisors if the space is closed?
Simple closure
Space closure ‘plus’
What are the advantages of RBBs for missing upper lateral incisors?
Relatively simple
Can do when patient is young
Non-destructive
Can look good
Place on a semi-permanent basis
What are the disadvantages of RBBs for missing upper lateral incisors?
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
What is needed for an implant for replacing missing upper lateral incisors?
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
What is space closure plus?
Alterations in tooth shape and size made
Changes in tooth colour made
Alteration in gingival architecture made
What are the advantages of space closure plus?
No prosthesis so relatively low maintenance
Good aesthetics with appropriate orthodontic and restorative technique
Can be done at any age
How is a RBB for a missing upper lateral carried out?
Mesial cantilever on canine due to root lengths, crown dimensions and less shine through
