Hypodontia

Question 1

definition of hypodontia

Answer 1

congenitally missing one or more teeth

Question 2

definition of andodontia

Answer 2

complete absence of teeth

Question 3

definition of severe hypodontia

Answer 3

six or more congenitally absent teeth

Question 4

what percentage of population does hypodontia affect

Answer 4

6%

Question 5

what are the most effected teeth by hypodontia

Answer 5

L5s
U2s
L5s
lower incisors

Question 6

what is the link between the teeth that are most commonly missing

Answer 6

usually the last in the series

Question 7

what is the lateral incisor mesio-distal width

Answer 7

around 7mm

Question 8

what percentage of the population is affected by missing laterals

Answer 8

2%

Question 9

what is the non-syndromic aetiology of hypodontia

Answer 9

mutations of at least 3 genes associated with missing teeth
familial
sporadic

Question 10

what syndromes are associated with hypodontia

Answer 10

cleft lip and palate
anhydrotic ectodermal dysplasia

Question 11

what environmental factors are associated with hypodontia

Answer 11

trauma
radiotherapy/ chemotherapy

Question 12

state four ways in which hypodontia can present

Answer 12

delayed/ asymmetric eruption
disorder of sequence of eruption
retained or infra-occluded deciduous teeth
absent deciduous teeth

Question 13

when should a patient with microdontia be referred

Answer 13

when there has been an abnormal presentation (sequence/ infraocclusion)
lack of space

Question 14

what problems are associated with hypodontia

Answer 14

microdontia
short roots
impaction
delayed formation
taurodontism

Question 15

what is taurodontism

Answer 15

elongated pulp chamber - particularly found in the 7s

Question 16

what investigations are used in the management of a hypodontia patient

Answer 16

study models
radiographs
photographs
cone beam CT

Question 17

what are the treatment options for managing hypodontia

Answer 17

accept
restorative treatment only
orthodontic treatment only
orthodontic and restorative treatment

Question 18

what are the options for managing hypodontia when using a restorative and orthodontic approach

Answer 18

open or close space

Question 19

what is the MDT management of missing upper laterals with space open

Answer 19

RBB
implant
partial denture

Question 20

what is the MDT management of missing upper laterals with space close

Answer 20

simple closure
space close plus

Question 21

what is the benefit of using partial dentures in hypodontia cases

Answer 21

useful if multiple teeth missing
not as destructive to tooth surface
intermediate option

Question 22

what is a disadvantage of partial dentures for hypodontia cases

Answer 22

you have to wait at least 3 months after treatment before using

Question 23

what is the benefit of using RBB for hypodontia cases

Answer 23

more forgiving of size discrepancies
simple
can do when young and looks good

Question 24

what are the disadvantages of treatment of hypodontia with a RBB

Answer 24

failure rate is high - if they fail they are going to fail early
patients have to be good at wearing a retainer

Question 25

how much space do you ideally require for implant treatment of hypodontia cases

Answer 25

7mm

Question 26

from what age can you offer implants

Answer 26

21 realistically but better to get when 23+ and sure growth has stopped