Hypodontia

Question 1

What is the definition of hypodontia?

Answer 1

Congenital absence of one or more teeth.

Question 2

What is anodontia?

Answer 2

Congenital absence of all teeth.

Question 3

What classes as severe hypodontia?

Answer 3

Congenitally missing 6 teeth or more.

Question 4

Describe the prevalence of hypodontia.

Answer 4

Prevelant in about 6% of people (excluding the 8s)
More common in females
1% of primary dentition
Most common teeth missing
- 8s
- 5s
- Upper 2s
- Lower incisors

Associated with ectopic canines

Question 5

Describe the aetiology of hypodontia.

Answer 5

Syndromatic
- Associated with specific craniofacial development syndromes
- CLP
- Anhydrotic ectodermal displasia

Non-syndromatic
- Mutations in genes associated with hypodontia
- Sporadic
- Familial history

Environmental
- Trauma
- Radiotherapy/chemotherapy

Question 6

What are the clinical signs that might make you suspect hypodontia?

Answer 6

Delayed/asymmetric eruption
Retained or infra-occluded primary teeth
Absent deciduous teeth

Question 7

What other issues can hypodontia be associated with?

Answer 7

Macrodontia
Malformation of teeth
Short root anomaly
Impaction
Delayed eruption
Enamel hypoplasia
Altered craniofacial growth
Crowding/malposition

Question 8

What problems can develop from hypodontia?

Answer 8

Spacing
Drifting
Over-eruption
Aesthetic impairment
Functional issues

Question 9

What are the treatment options for hypoplasia?

Answer 9

Accept
Restorative alone
Orthodontics alone
Combined orthodontics and restorative

Question 10

What restorative options are there for missing upper laterals?

Answer 10

Resin retained bridge
Implant
RPD
Autotransplantation
Conventional bridgework

Question 11

What are the advantages for doing a resin retained bridge for a missing upper 2?

Answer 11

• Relatively simple
• Do when young (complete treatment)
• Non-destructive
• Can look good
• Place on semi-permanent basis

Question 12

What are the disadvantages for doing a resin retained bridge for a missing upper 2?

Answer 12

• Failure rate
• Appearance sometimes not good, (try again, new materials)
• Orthodontic retention needs are high
• Predictable aesthetics?

Question 13

What are the implications of replacing a missing upper 2 with an implant?

Answer 13

• Can’t do implant till growth has ceased – now 21+
• Need minimum 7mm space
• Root separation!
• Often need bone graft
• Technically very demanding in aesthetic zone
• Significant extra time to do
• Significant cost

Question 14

What are the advantages of closing a missing upper 2 with orthodontics?

Answer 14

• No prosthesis – relatively low maintenance
• Good aesthetics with appropriate orthodontic and restorative techniques
• Can be done at an early age