Hypodontia Flashcards
What is hypodontia?
congenital absence of one or more teeth
What is anodontia?
complete absence of teeth
What is considered severe hypodontia?
6 or more congenitally absence in teeth
What is the prevalence of hypodontia (excluding 8s)
approximately 6%
What teeth are most commonly affected by hypodontia?
- 8s
- lower 5s
- upper 2s
- upper 5s
- lower incisors
What is the prevalence of missing upper laterals and what can this be associated with?
- 1-2%
- approximately 20% of all missing teeth
- most hypodontia cases
- associated with ectopic canines
What is the aetiology of hypodontia?
- non-syndromic
- mutations in at least 3 genes
- associated with missing teeth
- familial
- sporadic
- mutations in at least 3 genes
- syndromic
- > 100 craniofacial syndromes associated
- cleft lip and palate
- anhydrotic ectodermal dysplasia
- > 100 craniofacial syndromes associated
- environmental
- trauma
- radiotherapy or chemotherapy
How does hypodontia present?
- delayed or asymmetrical eruption
- retained or infra-occluded deciduous teeth
- absent deciduous tooth
- tooth form
What are the possible associated problems with hypodontia?
- microdontia
- malformation of other teeth
- short root anomaly
- impaction
- delayed formation or eruption of other teeth
- crowding or malposition of other teeth
- maxillary canine/first premolar transposition
- taurodontis,
- enamel hypoplasia
- altered craniofacial growth
What are the potential problems associated with hypodontia?
- spacing
- drifting
- reduction in space for prosthetic
- unfavourable sized spaces
- centreline shift
- over-eruption
- reduction in space for prosthetic
- aesthetic impairment
- functional problems
- particularly with multiple missing teeth
What is the hypodontia care pathway?
- GDP recognition
- especially infraocclusion
- referral to specialist orthodontist
What are the keys to successful management of hypodontia?
- inter-disciplinary team
- joint assessment and treatment planning
- precise aims
- joint collaboration at transitional stages
- follow up of treated case
What does assessment and planning for management of a hypodontia case involve?
- history
- extraoral examination
- intraoral examination
- orthodontic aspects
- skeletal relationship
- crowding
- restorative aspects
- size of central incisors
- space in occlusion
- caries
- smile line
- orthodontic aspects
- investigations
- problem list
- definitive plan
- retention/maintenance
What investigations should be carried out for hypodontia cases?
- study models
- planning models
- Kesling
- diagnostic
- radiographs
- photographs
- cone beam CT
- volume of bone available
- abnormal tooth forms
What are the options for replacement of missing upper lateral incisors?
- accept
- restorative alone
- orthodontics alone
- combined orthodontic and restorative treatment
What does combined orthodontic and restorative treatment involve?
- space open
- resin bonded bridge
- implant
- partial denture
- space closed
- simple closure
What should an orthodontic treatment plan consider?
- satisfied expected aesthetic objectives
- least invasive
- satisfies expected functional objectives
- immediate
- long term
- 65+ years
What is the most common replacement for missing teeth in hypodontia cases?
resin bonded bridges
How can resin bonded bridges be used for hypodontia cases?
- better success rates with cantilevers
- ideal abutment is canine
- root length
- crown dimensions
- less shine through of metal retainer
- technique sensitive
- grade
- experience of operator important
What are the advantages of resin bonded bridges?
- relatively simple
- can be carried out when young
- complete treatment
- non-destructive
- can provide good aesthetics
- placed on a semi-permanent basis
What are the disadvantages of resin bonded bridges?
- relatively high failure rate
- 18% at 5 years
- if survived at 5 years will make 10
- appearance not always idea
- can attempt again
- different material
- must wait 3 months
- gingival re-contouring
- orthodontic retention needs are high
- poorer success rates in canine position
- canine guidance
- forces applied
- canine guidance
What can be used to determine the space available for an implant?
- gauge
- radiograph
- CBCT
What are the key differences between resin bonded bridges and implants?
- can’t do implants until growth has finished
- 21+
- need minimum 7mm space for implants
- root separation
- often need to bone grafting for implants
- placed in a technically demanding zone
- highly aesthetic zone
- implants take significantly more time
- implants are significantly more expensive
What must be considered during space closure?
- tooth shape and size
- tooth colour
- gingival architecture
