Hypodontia

Question 1

What is hypodontia?

Answer 1

Congenital absence of one or more teeth

Question 2

What is severe hypodontia

Answer 2

6 or more congenitally missing teeth

Question 3

Prevalence of hypodontia?

Answer 3

6% excluding 8’s permanent dentition

0.9% primary dentition

Question 4

Most affected teeth in hypodontia?

Answer 4

8’s

L 5’s

U 2’s 1-2%, associated with ectopic canines

U 5’s

L incisors

Question 5

Aetiology of hypodontia?

Answer 5

Non-syndromic
- mutations in genes
- can be familial

Syndromic
- >100 craniofacial syndromes associated w/hypodontia
- ectodermal dysplasia / CLP common

Environmental
- trauma
- chemotherapy / radiotherapy

Question 6

How might one with Hypodontia typically present?

Answer 6

• delayed or asymmetric eruption
• retained or infra occluded deciduous teeth
• abnormality of tooth form
• impacted teeth
• taurodontism
• enamel defects

Question 7

When refer hypodontia?

Answer 7

Severe infraocclusion

Contra lateral tooth not erupted within 6 months

Altered sequence of eruption

Question 8

What dental issues may arise from hypodontia

Answer 8

Spacing

Drifting

Over -eruption

Aesthetic impairment

Functional problems

Question 9

Main investigations for hypodontia

Answer 9

Study models - can be used for diagnostic wax ups

Radiographs

Photographs

CBCT - volume of bone available? Fuck knows idek to locate teeth

Question 10

Options for hypodontia management

Answer 10

Accept

Ortho alone

Restorative alone

Combined tx

Question 11

What are the possible management options for missing upper laterals if space is being opened?

Answer 11

RBB

Implant

Conventional bridgework

Autotransplantation

Partial denture

Question 12

Advantages of using an RPD in hypodontia?

Answer 12

Replace multiple teeth in arch in one go

Can aid in replacing soft tissue

Question 13

Advantages of RBB in hypodontia?

Answer 13

Relatively simple

Can be done when young

Non destructive if no prep

Place on semi permanent basis

Question 14

Disadvantages of RBB

Answer 14

Failure rate!

Appearance not always ideal

Orthodontic retention needs are high

Aesthetics not always predictable

Question 15

When can restorative work be carried out after fixed ortho treatment?

Answer 15

At least 3 months after so soft tissues have stabilised

Question 16

What is the ideal RBB for laterals?

Answer 16

Cantilever design with canine as abutment
- root length
- crown dimensions
- less shine through from the wing

Question 17

Failure rate RBB?

Answer 17

80% 5 years but

If you make it to 5 years very likely to make it to 10 years

Question 18

When can an implant be placed to replace upper laterals?

Answer 18

Growth ceased 21+

Minimum 7mm space

Often need bone graft

When cost isn’t an issue

When root separation is adequate

Question 19

Issues w implants for hypodontia laterals?

Answer 19

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

Question 20

Supplemental tooth vs supernumerary?

Answer 20

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

Question 21

What is hypodontia ‘simple space closure’

Answer 21

Simple orthodontic movement to close space

Question 22

What is hypodontia space closure plus

Answer 22

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