Hypodontia

Question 1

definition of hypodontia

Answer 1

congenital absence of one or more teeth

Question 2

severe hypodontia

Answer 2

congenital absence of 6 or more teeth

Question 3

anodontia

Answer 3

complete absence of teeth

Question 4

what percentage of the population is affected by hypodontia (excluding 8s)

Answer 4

approx 6%

Question 5

is hypodontia more common in the primary or permanent dentition

Answer 5

permanent
rare in primary - if patient has hypodontia of primary dentition likely to be subsequent hypodontia of adult teeth

Question 6

what teeth are most commonly affected by hypodontia

Answer 6

(8s), upper 2s, lower 5s and upper 5s
(last tooth in a series)

Question 7

what other dental anomaly is hypodontia associated with

Answer 7

ectopic canines

Question 8

what are the 3 potential aetiologies of hypodontia

Answer 8

syndromic
non syndromic e.g sporadic or genetic
environmental - radio/chemo therapy, trauma

Question 9

name 6 dental anomalies associated with hypodontia

Answer 9

microdontia
malformation on teeth
short root anomaly
impaction
tarodontism
enamel hypoplasia
maxillary canine/ 1st premolar transposition
delayed formation or eruption of other teeth
altered craniofacial growth

Question 10

what is tarodontism

Answer 10

elongated pulp chamber - chamber floor is below ECJ
most common in 2nd molars

Question 11

name 3 features of anyhydrotic ectodermal dysplasia

Answer 11

hypodontia
abnormalites of tooth form
sweating

Question 12

name 4 potential problems that can arise due to hypodontia

Answer 12

spacing
drifting - can cause problems for restorative work
over eruption (if no opposing tooth)
aesthetic impairment
functional problems (particularly if severe hypodontia)

Question 13

what are the 4 management options for hypodontia patients

Answer 13

1. accept , no treatment
2. restorative treatment only
3. orthodontic treatment only
4. restorative and orthodontic treatment

Question 14

management options if space opened (upper lateral)

Answer 14

1. resin bonded bridge
2. conventional bridge
3. implant
4. partial denture
5. auto transplantation (rare)

Question 15

discuss a partial denture as a treatment option for hypodontia

Answer 15

pros: can restore multiple missing teeth in different areas of the arch, can give good aesthetic results, can provide soft tissue replacement, can be added to if poor prognosis of other teeth
cons: not all patients want or tolerate dentures, multiple visits required

Question 16

discuss resin bonded bridges as a treatment option for hypodontia

Answer 16

pros: only 2 visits required, can be forgiving of size discrepancy (can have large or small tooth), non destructive
cons: technique sensitive, may require fixed retainer to prevent relapse of ortho work if done prior to restorative, failure rate

Question 17

what are 4 key differences between implants and resin bonded bridges

Answer 17

• cant do implants until growth has finished (23 years +)
• need minimum 7mm space for implants
• root separation required for implants
• significant extra cost and time for implants
• implants have greater success rates

Question 19

what is meant by space closure plus

Answer 19

space closure via orthodontics in addition to restorative work to improve aesthetics - alterations to tooth shape and size, tooth colour and gingival architecture

Question 19

how is a canine made to look like a lateral

Answer 19

• individualised extrusion of canine to achieve more aesthetic gingival height (lower) relative to U1
• reshape the canine (remove point)
• bleach canine (canine usually more yellow)

Question 20

how is a premolar made to look like a canine

Answer 20

• intrude 4 to achieve aesthetic gingival margin (canines have higher gingival margins)
• rotate to increase the space taken up
• composite build up to ‘caninise’

Question 21

advantages to space closure rather than space open for hypodontia patients

Answer 21

• low restorative burden
• no prosthesis (low maintenance)
• can be done at an early age
• good aesthetics