Hypodontia

Question 1

what is hypodontia?

Answer 1

CONGENITAL absence of one or more teeth

Question 2

what is anodontia?

Answer 2

Complete absence of all teeth
[VERY VERY RARE]

Question 3

what is severe hypodontia?

Answer 3

6 or more CONGENITALLY absent teeth

Question 4

whats the prevalence of hypodontia?

Answer 4

approx 6%

Question 5

what teeth are most affected by hypodontia?

Answer 5

8s, Lower 5s, Upper 2s, Upper 5s

Upper laterals common

Question 6

what are some non-syndromic causes of hypodontia?

Answer 6

• Familial history of hypodontia
• Sporadic
• Mutations

Question 7

what are some syndromic causes of hypodontia?

Answer 7

• Cleft lip & palate
• anhydrotic ectodermal dysplasia

Question 8

what are some environmental causes of hypodontia?

Answer 8

• trauma
• radiotherapy/chemotherapy

Question 9

How would a pt with hypodontia present with on a clinic?

Answer 9

• delayed or asymmetric eruption
• retained or intra-occluded deciduous teeth
• absent deciduous tooth
• tooth form

Question 10

what are the associated problems with microdontia?

Answer 10

• malformation of other teeth
• short root
• impaction
• delayed formation/eruption of other teeth
• enamel hypoplasia

Question 11

what problems can arise as a result of hypodontia?

Answer 11

• spacing
• drifting
• over-eruption
• aesthetic impairment
• functional problems

Question 12

what is the hypodontia care pathway?

Answer 12

• GDP Recognition
• Referral to Specialist Orthodontist
• If appropriate, passed onto Hypodontia clinic (Ortho + Restorative input)

Question 13

what investigations would be useful for a hypodontia patient?

Answer 13

• study models
• radiographs
• photographs
• Conebeam CT

Question 14

what are the general treatment options for a pt with missing laterals?

Answer 14

• Accept
• Ortho alone
• Restorative alone
• Ortho & Restorative combined

Question 15

if a pt has missing upper laterals what restorative tx options are available if there is an open space?

Answer 15

Common:
- resin bonded bridge
- implant
- partial denture

Less common:
- auto transplantation
- conventional bridgework

Question 16

what are the advantages & disadvantages of a resin bonded bridge for a hypodontia patient?

Answer 16

Advantages
- simple
- non destructive
- aesthetically pleasing

Disadvantages
- it fails (comes off)
- appearance sometimes not ideal around gingival margins if high smile line
- pt needs good orthodontic retention so teeth dont drift

Question 17

what are the key differences between a RBB vs Implant?

Answer 17

• cant do implant until pt has fully grown (21+)
• cost is high, lots of time needed
• sometimes bone graft required
• technique sensitive especially around gingival margins
• (spacing) implants need ~7mm space minimum so that the implant does not damage adjacent teeth roots

Question 18

in a hypodontia tx plan, how do you make an upper canine look like a lateral incisor?

Answer 18

• fixed appliance that will EXTRUDE canine resulting in the gingival contour also changing to match a lateral incisor (lower gingival contour)
• significant reshape of canine (make more flat)
• bleaching (canines darker than laterals)

Question 19

how do you make an upper premolar look like a canine?

Answer 19

• intrude premolar so gingival contour matches a regular canine. (higher gingival contour)
• rotate the tooth to take up space
• composite build up to match anatomy of canine