Provisional extra coronal restorations Flashcards
What is a provisional extra coronal restoration?
A restoration provided between tooth preparation and fit of an indirect extra coronal restoration
Provisional restoration function
tooth preparation
- compromises aesthetics in smile lines
- degrades of tooth function (occlusion reduction and destabilised occlusion)
occlusal and inter proximal reduction:
- may render a tooth sensitive due to exposed dentine
- compromised coronal seal o RCT’d tooth
provisionals restore these characteristics
A provisional restoration should…
have good marginal fit
be well contoured
- no overhangs
be cleanable and maintainable by patient
establish and/or maintain dental aesthetics, mimicking either
- original tooth
OR
- definitive restoration
prevent sensitivity
allow optimum home care
prevent micro leakage
- preserve tooth vitality
consequences of a poor fitted and poorly contoured provisional restoration
patient unable to clean
- caries
- gingival inflammation
- poor moisture control
- gingival overgrowth
Functional characteristics of a provisional
confirm tooth prep is adequate
occlusal stability
- no changes in OVD unless desired
- prevent drifting or tilting of prepared teeth
preserve or improve function
- mastication
- speech
desirable properties of provisional materials
non irritant
low temperature rise on setting
dimensionally stable
adequate working and setting times
adequate strength and wear resistance
good aesthetics
types of provisional restorations
custom formed
preformed
features of a custom formed provisional restoration
- bespoke to individual situations
- preferable
- can be technically demanding
features of a preformed provisional restoration
- standard shape and sizes
- adjusted to fit chair side
material used for custom resin provisional crowns
chemically cured bis-acrylic composite resin
outline method for impression taking for custom resin provisional crowns
sectional impression
prep tooth for chosen restoration
syringe bis-acrylic composition resin material onto mixing pad
- ensure it is mixed
- monitor setting
syringe material into sectional impression
relocate impression into mouth
- ensure full seated
- should click over bulbosity of remaining teeth
remove before complete polymerisation
remove completely
- may stay on tooth - gently ease off with instrument beneath contact points
remove flash and ledges
- high speed and/or polishing discs
outline steps taken for checking provisional restoration
confirm tooth preparation
- Svenson gause
check marginal fit and occlusion in situ
check aesthetics
cement provisional restoartion
- temporary luting cement
- trim away excess
how to establish occlusion and aesthetics its a provisional restoration
loss of original tooth form e.g. wear cases:
- re-establish tooth shape
- trial occlusion and aesthetics using provisional restoration
guidance (anterior/incisal)
- produce on crowns:
diagnostic wax up
articulated study models
faccebow registration
types of preformed provisional crowns
tooth coloured
- polycarbonate
- clear plastic crown forms - filled with composite
metal
- aluminium
- stainless steel
preformed provisional crown - problems
unlikely to fit accurately
- cervically
- occlusally
- interdentally
large bank of crowns needed
- to accommodate variation between patients
- costly
