Hypodontia Flashcards
What is hypodontia?
Congenital absence of one or more teeth
What is severe hypodontia
6 or more congenitally missing teeth
Prevalence of hypodontia?
6% excluding 8’s permanent dentition
0.9% primary dentition
Most affected teeth in hypodontia?
8’s
L 5’s
U 2’s 1-2%, associated with ectopic canines
U 5’s
L incisors
Aetiology of hypodontia?
Non-syndromic
- mutations in genes
- can be familial
Syndromic
- >100 craniofacial syndromes associated w/hypodontia
- ectodermal dysplasia / CLP common
Environmental
- trauma
- chemotherapy / radiotherapy
How might one with Hypodontia typically present?
- delayed or asymmetric eruption
- retained or infra occluded deciduous teeth
- abnormality of tooth form
- impacted teeth
- taurodontism
- enamel defects
When refer hypodontia?
Severe infraocclusion
Contra lateral tooth not erupted within 6 months
Altered sequence of eruption
What dental issues may arise from hypodontia
Spacing
Drifting
Over -eruption
Aesthetic impairment
Functional problems
Main investigations for hypodontia
Study models - can be used for diagnostic wax ups
Radiographs
Photographs
CBCT - volume of bone available? Fuck knows idek to locate teeth
Options for hypodontia management
Accept
Ortho alone
Restorative alone
Combined tx
What are the possible management options for missing upper laterals if space is being opened?
RBB
Implant
Conventional bridgework
Autotransplantation
Partial denture
Advantages of using an RPD in hypodontia?
Replace multiple teeth in arch in one go
Can aid in replacing soft tissue
Advantages of RBB in hypodontia?
Relatively simple
Can be done when young
Non destructive if no prep
Place on semi permanent basis
Disadvantages of RBB
Failure rate!
Appearance not always ideal
Orthodontic retention needs are high
Aesthetics not always predictable
When can restorative work be carried out after fixed ortho treatment?
At least 3 months after so soft tissues have stabilised
What is the ideal RBB for laterals?
Cantilever design with canine as abutment
- root length
- crown dimensions
- less shine through from the wing
Failure rate RBB?
80% 5 years but
If you make it to 5 years very likely to make it to 10 years
When can an implant be placed to replace upper laterals?
Growth ceased 21+
Minimum 7mm space
Often need bone graft
When cost isn’t an issue
When root separation is adequate
Issues w implants for hypodontia laterals?
Recession of gingival margin / poor gingival margins
- very technically demanding
- significant time to carry out
- cost
- can go very wrong when they do go wrong
Supplemental tooth vs supernumerary?
Supplemental tooth is a supernumerary of the same morphology of another tooth
Supernumerary can be different e.g. smaller or no resemblance e.g. odontome
What is hypodontia ‘simple space closure’
Simple orthodontic movement to close space
What is hypodontia space closure plus
Close space by moving canine and make it look like a lateral
- cuspal reduction
- extrude to match gingival margin level
Bring other teeth forward with 4 into 3 space
- alter 4 to look like 3
