Occlusal Factors in Restoration Failure Flashcards
What can go wrong if occlusion is not maintained when doing a restoration
- Teeth and restorations can fracture
- Increased mobility
- pain on biting
- Loosening of crowns
How can occlusion cause restoration failure
Due to excessive forces being placed on the tooth or forces being applied to the tooth in the wrong direction
What can cause excessive pressure to be applied on teeth
Premature contacts (interferences)
What are interference caused by
Premature contacts
How can we prevent the occlusion from causing restoration failure
Performa a good occlusal screening examination on every patient
What do we need to record when carrying out an occlusal examination
- ICP
- Lateral guidance
- Look for repeated restoration failures
- Look for protrusion on heavily restored anteriors
- Record any wear facets on at risk teeth
- RCP-ICP slide when anterior wear is seen
- Non working side interferences
What questions do we ask when describing ICP
- Is it stable and healthy or unstable
- Is it damaging to the teeth
- Is there sufficient room for restorations
What are the 2 types of lateral guidance
- Canine guidance
2. Group function
On which teeth/ tooth should lateral guidance NEVER be on ?
- A post crowned tooth
2. A bridge pontic
How can we plan how to work around and maintain occlusion
Create a diagnostic wax up
What is an interference
Is a heavy tooth to tooth contact that prevents the jaw from moving through its intended path
How might a patient describe ICP interferences
As high spots when biting
What can ICP interfaces lead to
- Pain
- Increased mobility
- Increased tooth sensitivity
- Failure of restoration
Why does a working side interference occur
Occurs due to lack of canine guidance protecting posterior teeth
Which cusps are affected by lateral forces on the working side
Buccal cusp in Upper
Lingual cusps in Lowers
(BULL)
What is the bull rule
The fact that Buccal cusp in Upper and Lingual cusps in Lowers are usually affected by lateral movement son the working sied
What is non working side interferences
Occurs when teeth on the non working side clash during lateral movement
Why are non working side interference less common
As the non working side condyle normally takes the teeth apart
Which cusps are usually affected by lateral forces on the non working side
Palatal Upper
Buccal Lower
What do we typically see on upper teeth if they are experiencing non working side interferences
A semi circular wear pattern
How can we stop occlusion from causing restoration failure
- Make occlusal exam part of the check up
- Make the occlusion feel the same for the patient after treatment
- Choose the articulator to match the risk of lateral forces
How can we correct a crown that is high in ICP and high in lateral excursions
Reduce the cusp height
How can we correct a crown that is high in ICP BUT free in lateral excursions
Deepen the fossa
If we want to re instate canine guidance what must we check for
The canines:
- Periodontal status
- Pulp vitality
- Perioapical radiogrpah
- Root length
- Is it RCT or crowned?
