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 teeth are most affected by hypodontia
- 8s
- L5s
- U2s
- U5s
- lower incisors
aetiology of hypodontia
- Non-syndromic
- mutations in at least 3 genes associated with missing teeth in non-syndromic hypodontia
- familial
- sporadic - Syndromic
- >100 craniofacial syndromes assoc with hypodontia - Environmental
- trauma
- radio/chemo therapy
presentation of hypodontia
- delayed or asymmetric eruption
- retained/infra occlused primary teeth
- absent primary tooth (permanent tooth germ develops from primary)
- tooth form
associated problems with hypodontia
- microdontia
- malformation of other teeth
- short root anomaly
- impaction
- delayed formation and/or delayed eruption other teeth
- crowding and/or malposition of other teeth
- max canine/first premolar transposition
- taurodontism (enlarged pulp chambers)
- enamel hypoplasia
- altered craniofacial growth
name a syndrome associated with hypodontia
anhydrotic ectodermal dysplasia
- absent sweat glands
- hair thin
- absent lower teeth
potential problems of hypodontia
- spacing
- drifting
- over-eruption
- aesthetic impairment
- functional problems
Tx option for this case:
- absent U2s
- ectopic canines
- midline diastema
- extraction URb, ULb
- sectional fixed appliance to close space between UR1 and UL1
- allows eruption UR3 and UL3
keys to successful management of hypodontia cases
- inter-disciplinary team
- joint assessment and tx planning with precise aims
- joint collaboration at transitional stages of tx
- follow up of treated cases
investigations for hypodontia
- study models
- planning models
- radiographs
- photographs
- CBCT
options for missing lateral incisors
- accept
- restorative alone
- ortho alone
- combined restorative and ortho
ortho options for missing upper lateral incisors
Open space
- RBB
- autotransplantation
- implant
- partial denture
- conventional bridge
Close space
- simple
- space closure plus
how to chose tx option
- satisfies expected aesthetic objectives
- least invasive
- satisfies expected functional objectives
how to chose tx option
- satisfies expected aesthetic objectives
- least invasive
- satisfies expected functional objectives
what has happened here
labial rotation of lateral incisor cantilever pontics due to mesial relapse of canines
if using a RBB to replace missing incisor, which tooth would you use as the abutment
canines if possible
- root lenght
- crown dimensions
- less shine through
advantages of RBBs
- relatively simple
- do when young
- non-destructive
- can look good
- place on semi-permanent basis e.g. until old enough for implant
disadvantages of RBBs
- failure rate
- appearance sometimes not goot
- ortho retention needs are high
how much space is needed for an implant
7mm
RBB vs implant
- can’t do implant til 18-19 yrs old
- need minimum 7mm
- root separation
- often need bone graft
- technically very demanding in aesthetic zone (metal work can be visible due to recession)
- significant extra time to do
- cost high
how can you help aesthetics if doing simple space closure
- disguising canines as laterals with composite
- disguising premolars as canines with composite
what would space closure plus include
adjusting:
- tooth shape/size
- tooth colour
- gingival architecture
