Hypodontia

Question 1

What is hypotonia?

Answer 1

The congenital absence of one or more teeth

Question 2

What is anodontia?

Answer 2

Complete absence of teeth

Question 3

What is classes as severe hypodontia?

Answer 3

6 or more congenitally absent teeth

Question 4

What are the most commonly affected teeth in hypodontia?

Answer 4

Lower 5s
Upper 2s
Upper 5s

Question 5

What are common clinical findings alongside missing upper laterals

Answer 5

Ectopic canines are common in these cases

Question 6

What is the aetiology of hypodontia?

Answer 6

Can be non syndromic - mutations in at least 3 genes (familial or sporadic).
Or syndromic - associated with craneofacial syndromes eg. CLP, anhydrotic ectodermal dysplasia.
Or can be environmental - eg trauma to primary, radiotherapy/ chemotherapy

Question 7

What is anhydrotic ectodermal dysplasia?

Answer 7

Craneofacial syndrome which results in abnormalities in tooth from (pointed shape), hypodontia and disrupted temperature control (excess sweating).

Question 8

What is the common presentation of hypodontia?

Answer 8

Delayed or asymmetric eruption
Retained or infra occluded teeth
Absent deciduous teeth
Tooth form altered

Question 9

What are some dental problems associated with hypodontia?

Answer 9

Microdontia
Malformation of other teeth
Short root anatomy
Imp action
Enamel hypoplasia
Taurodontism

Question 10

What is taurodotnism?

Answer 10

Elongated pulp chamber (below floor of CEJ), common in 7s, makes endo difficult.

Question 11

What are some potential problems caused by hypodontia?

Answer 11

Spacing and drifting (unfavourable gaps for restorative treatment)
Overeruption of teeth into gaps
Aesthetic immpairement
Functional impairment if severe

Question 12

When should hypodontia cases be referred?

Answer 12

When complete absence of space for tooth eruption, abnormalities in sequence, severely infraoccluded teeth.

Question 13

What causes teeth to be infraoccluded?

Answer 13

Ankylosis to alveolar bone gives the appearance tooth is submerged compared to adjacent teeth and gingiva wich are growing normally).

Question 14

Who is involved in MDT care of hypodontia patient?

Answer 14

GDP
Specialist orthodontis
Pads dentist
Restorative dentist

Question 15

What are the management options for hypodontia

Answer 15

Accept
Restorative only
Ortho only
Combined ortho and restorative

Question 16

What is involved in the assessment for treatment planning of hypodontia?

Answer 16

Ortho - skeletal pattern, crowding, occlusion
Restorative - size of centrals, space in occlusion for pros work, smile line

Question 17

What is involved with restorative management?

Answer 17

Partial denture - if multiple spaces, soft tissue replacement, can be used until gingiva settles.

Resin bonded bridges - often provide with bonded retainer to ensure no movement of teeth, simple treatment, non destructive, good aesthetics although not ideal if high smile line.

Implant - good success rate although complications are difficult if failure.

Question 18

In pt with missing upper laterals, what is a common treatment option?

Answer 18

Resin bonded bridge, using canine as abutment

Question 19

Why is canine an ideal abutment for resin bonded cantilever bridges?

Answer 19

Root length and Crown dimensions are favourable
Less shine through than central incisors.

Question 20

What are the requirements for implant placement?

Answer 20

Minimum 7mm space
Cannot place until 21 yo
Need sufficient space (between roots) and sufficient bone

Significant cost