Hypodontia Flashcards
What is hypodontia defined as
Congenital absence of one or more teeth
What is anodontia defined as
Complete absence of teeth
What is severe hypodontia defined as
o >6 more congenitally absent teeth
o Permanent teeth
o Doesn’t include third molars
What is severe hypodontia defined as
o >6 more congenitally absent teeth
o Permanent teeth
o Doesn’t include third molars
What is the prevalence of hypodontia
6%
What are the teeth most effected by hypodontia
o 8s (not considered hypodontia however)
o Lower 5s
o Upper 2s
o Upper 5s
o Lower incisors
Why is hypodontia of upper 2’s most problematic
1-2% of population
Greatest effect on aesthetics
Associated with ectopic canines as laterals guide canines into position
What can the aetiology of hypodontia be split into
non-syndromic
syndromic
environmental
What is a non-syndromic aetiology
o Mutations in at least 3 genes associated with missing teeth in non-syndromic hypodontia i.e genetic tendency
o Familial
o Sporadic
What is a syndromic aetiology
o Craniofacial syndromes associated with hypodontia
o Examples: cleft lip & palate, anhidrotic ectodermal dysplasia
What is an environmental aetiology
o Trauma
o Radiotherapy/chemotherapy
What is the presentation of hypodontia
- Delayed/asymmetric eruption
- Retained or infraoccluded deciduous teeth
- Absent deciduous teeth
- Tooth form – more of a conical morphology, tend to be smaller
What are the associated problems with hypodontia
- Microdontia!!!!!!
- Malformation of other teeth
- Short root anomaly
- Impaction
- Delayed formation and/or delayed eruption of other teeth
- Crowding and/or malposition of other teeth
- Maxillary canine/first premolar transposition
- Taurodontism
- Enamel hypoplasia
- Altered craniofacial growth
What are potential problems caused by hypodontia
- Spacing
- Drifting
- Overeruption
- Aesthetic impairment
- Functional problems (usually requires quite a few teeth missing to reach this stage)
What is the hypodontia pathway
GDP recognition
Referral to specialist orthodontist
What are the options for upper lateral incisor hypodontia
accept
restorative alone
orthodontics alone
combined orthodontic and restorative treatment
What can the treatment pathways be split into
open the space
close the space
What are the options if we open the space
RRB
implant - gold standard
autotransplantation
partial denture
conventional bridge
What are the resin retained bridge used
cantilever
What is the gold standard abutment for RRB
canine due to root length, crown dimensions and reduced shine through
What are the advantages of RRB
o Simple
o Can do when young
o Non-destructive
o Can look good
o Can be placed on a semipermanent basis while px reaches appropriate age for implant (20/21 as requires vertical growth of alveolar processes to stop)
What are the disadvantages of RRB
o Failure rate
o Appearance sometimes not good
o Orthodontic retention needs are high to prevent relapse
What is the minimum age for implants
18-19
vertical growth of alveolar process must stop
What is the minimum space for implant
7mm
gingival level
How must the roots be for implants
Root separation required – roots must be parallel and not be leaning into the space the implant is to go into
What is often required to facilitate implants in hypodontia cases
bone graft
What are the disadvantages of implants
- Technically very demanding in aesthetic zone
- Significant extra time and cost required
What are the options if closing the space
accept space closure
close space and treat to make teeth look as natural as possible
How do you get a canine to look like a lateral
o Individualised extrusion of canine re-gingival contour height relative to U1
o Significant reshape of U3 – cusps flattened
o Bleaching U3 due to natural yellow shade of canine
How do you get a premolar to look like a canine
o Intrude U4 to give correct gingival architecture
o Rotate to take up more space
o Composite built up/veneer U4 to restore vertical height and get it to resemble canine
What are the advantages of close space plus
o No prosthesis – relatively low maintenance
o Good aesthetics with appropriate orthodontic and restorative techniques
o Can be done at an early age
