Occlusal Factors in Restoration Failure

Question 1

What can go wrong if occlusion is not maintained when doing a restoration

Answer 1

1. Teeth and restorations can fracture
2. Increased mobility
3. pain on biting
4. Loosening of crowns

Question 2

How can occlusion cause restoration failure

Answer 2

Due to excessive forces being placed on the tooth or forces being applied to the tooth in the wrong direction

Question 3

What can cause excessive pressure to be applied on teeth

Answer 3

Premature contacts (interferences)

Question 4

What are interference caused by

Answer 4

Premature contacts

Question 5

How can we prevent the occlusion from causing restoration failure

Answer 5

Performa a good occlusal screening examination on every patient

Question 6

What do we need to record when carrying out an occlusal examination

Answer 6

1. ICP
2. Lateral guidance
3. Look for repeated restoration failures
4. Look for protrusion on heavily restored anteriors
5. Record any wear facets on at risk teeth
6. RCP-ICP slide when anterior wear is seen
7. Non working side interferences

Question 7

What questions do we ask when describing ICP

Answer 7

1. Is it stable and healthy or unstable
2. Is it damaging to the teeth
3. Is there sufficient room for restorations

Question 8

What are the 2 types of lateral guidance

Answer 8

1. Canine guidance

2. Group function

Question 9

On which teeth/ tooth should lateral guidance NEVER be on ?

Answer 9

1. A post crowned tooth

2. A bridge pontic

Question 10

How can we plan how to work around and maintain occlusion

Answer 10

Create a diagnostic wax up

Question 11

What is an interference

Answer 11

Is a heavy tooth to tooth contact that prevents the jaw from moving through its intended path

Question 12

How might a patient describe ICP interferences

Answer 12

As high spots when biting

Question 13

What can ICP interfaces lead to

Answer 13

1. Pain
2. Increased mobility
3. Increased tooth sensitivity
4. Failure of restoration

Question 14

Why does a working side interference occur

Answer 14

Occurs due to lack of canine guidance protecting posterior teeth

Question 15

Which cusps are affected by lateral forces on the working side

Answer 15

Buccal cusp in Upper
Lingual cusps in Lowers
(BULL)

Question 16

What is the bull rule

Answer 16

The fact that Buccal cusp in Upper and Lingual cusps in Lowers are usually affected by lateral movement son the working sied

Question 17

What is non working side interferences

Answer 17

Occurs when teeth on the non working side clash during lateral movement

Question 18

Why are non working side interference less common

Answer 18

As the non working side condyle normally takes the teeth apart

Question 19

Which cusps are usually affected by lateral forces on the non working side

Answer 19

Palatal Upper

Buccal Lower

Question 20

What do we typically see on upper teeth if they are experiencing non working side interferences

Answer 20

A semi circular wear pattern

Question 21

How can we stop occlusion from causing restoration failure

Answer 21

1. Make occlusal exam part of the check up
2. Make the occlusion feel the same for the patient after treatment
3. Choose the articulator to match the risk of lateral forces

Question 22

How can we correct a crown that is high in ICP and high in lateral excursions

Answer 22

Reduce the cusp height

Question 23

How can we correct a crown that is high in ICP BUT free in lateral excursions

Answer 23

Deepen the fossa

Question 24

If we want to re instate canine guidance what must we check for

Answer 24

The canines:

1. Periodontal status
2. Pulp vitality
3. Perioapical radiogrpah
4. Root length
5. Is it RCT or crowned?