9 - Hypodontia Flashcards
Define hypodontia.
Congenital absence of one or more teeth
Define anodontia.
Complete absence of teeth
Define severe hypodontia.
6 or more congenitally absent teeth
What is the prevalence of hypodontia?
- 6% (excluding 8s)
- F>M
Which teeth are most commonly affected by hypodontia?
- last in the series
- 8s > L5s > U2s > U5s > lower incisors
3
What is the aetiology of hypodontia?
- non-syndromic: mutation in 3 genes associated, familial or sporadic
- syndromic: >100 craniofacial syndromes associated, CLP, anhydrotic ectodermal dysplasia
- environmental: trauma, radio/chemotherapay
4
Describe the presentation of hypodontia.
- delayed or asymmetric eruption
- retained or infra-occluded deciduous teeth
- absent deciduous teeth
- altered tooth form
13
What problems are associated with hypodontia?
- microdontia and malformation of other teeth
- short root anomaly
- impaction
- delayed formation/eruption of other teeth
- crowding
- maxillary canine/first premolar transposition
- taurodontism
- enamel hypoplasia
- altered craniofacial growth
- spacing, drifting
- overeruption (no interocclusal space for restorations)
- aesthetic impairment
- functional problems
Define taurodontism.
- elongated pulp chamber below CEJ
- usually unproblematic unless endodontic treatment or malformed teeth
- often seen in 7s
4
What are features of anhydrotic ectodermal dysplasia?
- no sweating
- malformed teeth
- microdontia
- space hair
What is the hypodontia care pathway?
- GDP recognition
- referral to specialist orthodontist
- referral to hospital service (MDT with joint assessment and collaboration, especially at transition points in treatment plan)
What is a Kesling planning model?
Teeth are removed from model to move around to assess best position
What benefit does CBCT have over plain radiography in hypodontia cases?
- localise any ectopic teeth
- assess bone volume for implant planning
What are the MDT treatment options for missing upper laterals?
Space open
- RBB
- implant
- RPD
Space close
- simple closure
- space close plus
5
What are the benefits of RPDs in hypodontia treatment?
- good soft tissue replacement
- replace multiple teeth in arch
- easy to construct
- non destructive
- intermediate to other treatment options
5
What are the benefits of RBB in hypodontia treatment?
- simple
- can be placed at young age
- non destructive
- good aesthetics
- can be placed on semi-permanent basis (ie prior to implant)
3
What are the disadvantages of RBB in hypodontia treatment?
- high failure rate (80% in five years)
- orthodontic retention needs are high
- RBB in canine position often fail due to high forces and lateral excursion
What are the requirements for placing an implant?
- wait until growth stopped, 21+
- 7mm space between adjacent roots
- often require bone graft
Why do you need to wait until growth has finished to place an implant?
- anterior vertical growth of maxilla
- if placed too early, implant would not “erupt” with bone and would appear ankylosed
What is space close plus?
- package of amendments after closure
- adjust gingival levels
- composite bonding
- tooth colour eg bleaching
4
What are the advantages of space close plus?
- no prosthesis
- low maintenance, reduced restorative burden as not beginning the cycle
- gingival levels can be adjusted with orthodontics
- can be done at early age
How can the gingival margins be manipulated using orthodontics?
- extrude canine to appear like lateral
- intrude and rotate premolar to appear like canine (hide second cusp)
