Provisional Extracoronal Restorations Flashcards
What are the clinical stages for indirect restorations?
Preparation
Temporisation
Impressions and registration
Cementation
What are the ideal properties of a provisional restoration?
Have good marginal fit
Be well contoured - no overhangs
Cleansable and maintainable by the patient
Establish or maintain dental aesthetics
Prevent sensitivity
Prevent microleakage
Keep occlusal stability
Preserve or improve function - mastication and speech
What happens if a patient is unable to clean a provisional restoration?
Can cause caries and gingival inflammation due to poor moisture control and gingival overgrowth
Give examples of desirable characteristics of a provisional restoration
Non-irritant - pulp and periodontal tissues
Low temperature rise during setting
Dimensionally stable
Adequate working time
Adequate setting time
Adequate strength and wear resistance
Good aesthetics
What are the different types of provisional restoration?
Custom formed - bespoke to individual situations, preferable but can be technically demanding
Preformed - standard shapes and sizes, adjust to fit at chairside
Which material is most commonly used for provisional crowns?
Protemp
Chemically cured bis-acrylic composite resin
What is a Svensen gauge used for?
A guide for how much tooth preparation is necessary
Describe impressions for provisional crowns
Sectional impression using President putty - addition cured silicone
What are provisional restorations useful for in terms of occlusion and aesthetics?
In wear cases can re-establish tooth shape and pilot occlusion and aesthetics
Can provide incisal guidance
Can use as a trial run for the definitive restoration
Guidance created from provisionals can be transferred to the definitive
Why is a custom incisal table used?
It allows the technician to ensure the occlusal contact points and the shape of the provisionals are replicated
What are the common types of preformed provisional crowns?
Tooth coloured - polycarbonate, clear-plastic crowns filled with composite
Metal - aluminium, stainless steel
What are the problems with provisional crowns?
Unlikely to fit accurately - occlusally, cervically, interdentally
Large bank of crowns needed - costly
When are preformed provisional crowns useful?
Situations where no impression has been taken prior to tooth preparation or damage eg - trauma cases
What other provisional restorations are available?
If replacing an old crown, can use the crown for the temporary
Preformed malleable composite crowns
Spot bonded composite for veneers
Indirect provisional restorations
Describe indirect provisional restorations
Lab made (usually acrylic)
More accurate
High strength
High cost and time consuming
