Overdentures

Question 1

Definition

Answer 1

An overdenture is one which gains its
support partly or wholly from the
roots of retained, decoronated (or
crown modified) teeth

Question 2

Advantages of retaining roots

Answer 2

1. The retained root preserves the associated
   alveolar bone
2. The root face gives extra support
3. Extra retention can be gained via attachments
4. Psychological benefit
5. Retained proprioception and tactile discrimination

Question 3

1. The retained root preserves associated alveolar bone

Answer 3

Enhances stability

Prevents resorption

Question 4

2. The root face gives extra support

Answer 4

Allows the tissues
to support greater
occlusal loads and
protects the soft
tissues against the
effects of
mechanical trauma

Question 5

3. Extra retention can be gained via attachments

Answer 5

CEKA and
magnetic
attachments
provide positive
retention

Question 6

4. Knowing that the remaining teeth will not be lost gives some patients reassurance

Answer 6

The psychological
benefits of
retaining teeth
should not be
underestimated

Question 7

5. Retained proprioception and tactile discrimination

Answer 7

Claimed
Certainly feedback from the periodontal ligament allows
better discrimination of particle sizes and textures

Question 8

Disadvantages of retaining roots

Answer 8

1. More expensive
2. Failure can occur due to caries
3. Takes longer

Question 9

1. More expensive

Answer 9

Primarily in carrying out root canal
treatment, but also because denture reinforcement
and/or extra retention is sometimes needed

Question 10

2. Failure can occur due to caries

Answer 10

The
retained roots are susceptible to caries in the protected environment under a
denture

Question 11

3. Takes longer

Answer 11

Although review is less expensive (fewer alterations needed),
preparatory work (RCT) and aftercare (primarily caries
prophylaxis) are more prolonged

Question 12

Cases in which overdenture treatment specially indicated

Answer 12

1. When it is thought that alveolar resorption will be
   significant.
2. When repeated alterations to dentures might be
   undesirable and extractions are contraindicated
3. When increases in face height are to be produced in
   cases of tooth wear or hypodontia
4. When it is thought that adaptation might be poor and
   extra retention is desirable

Question 13

1. When it is thought that alveolar resorption will be

significant

Answer 13

(Unopposed
mandibular
anterior teeth can
predispose to
maxillary atrophy)

Question 14

2. When repeated alterations to dentures might be

undesirable and extractions are contraindicated

Answer 14

(The elderly often
have problems with
transport and may
heal slowly)

Question 15

Individual tooth selection

Answer 15

• Root
-simple root canal shape: endodontics
-adequate root size
-sufficient support
• Tooth site
-near canine region
• Bone
-no buccal undercuts

Question 16

Tooth arrangement

Answer 16

Site
-bilateral tripod of support
-opposed if possible
Proximity
-not in contact

Question 17

Types of overdenture

Answer 17

1. Immediate – analogous to the
immediate complete
2. Transitional (temporary) – by addition
to a partial denture. Generally provided
to assess tolerance, caries rate, and
outcome
3. Permanent/ Replacement – a permanent
overdenture which often has extra
strengtheners or retaining mechanisms

Question 18

1. Immediate – type I, extractions necessary

Answer 18

Canines are to be
retained. Molar
and premolar are
to be extracted –
due to difficult
endodontics and
caries respectively

Question 19

2. Immediate - type II, no extractions

Answer 19

URincisors and canine are to be

preserved as denture abutments

Question 20

2. Transitional (temporary)

overdenture

Answer 20

Not quite analogous to the transitional partial
denture. Provided by extension of a current partial
denture or after making a temporary PD
Placement always carried out in
hope – which is either fulfilled later when permanent overdenture is placed, or frustrated
when a complete conventional denture is place

Question 21

Associated problems

Answer 21

1. Endodontics
2. Functional contact
3. Abutment form
4. Additional retention
5. Aftercare

Question 22

1. Endodontics

Answer 22

Overdentures on root filled teeth are more

successful that on non-root filled teeth

Question 23

2. Functional contact

Answer 23

If abutments on
model are longer
than the prepared
abutments