Provisional Extra Coronal Restoration Flashcards
What is a Extra-coronal provisional restoration?
- A restoration provided to patient between tooth prep and fit of an indirect restoration
- Should be of high-quality of failures can occur which can lead to problems
What do Extra-coronal provisional restorations have a role in?
- Immediate and long term health of the tooth and the supporting structures like PDL
- Success of definitive restorations
What are the clinical stages for indirect restoration?
- Preparation
- Temporisation
- Impressions and registrations
- Cementation
Success of each stage dependent on success of preceding stage
What are the characteristics of provisional restorations during tooth preparation?
- Compromise the aesthetics in smile line as we have cut away tooth tissue
- This degrades tooth function via occlusion reduction and destabilisation of occlusion
- Occlusal and IP reduction causes exposed dentine which leads to sensitivity
- Also can compromise coronal seal of RCT’d teeth in some cases
What must provisional restorations do?
- Establish or maintain dental aesthetics by mimicking the original tooth or definitive restoration
- Prevent sensitivity
- Allow optimum home care
- Prevent plaque build up and caries
- Maintain gingival health and contour
- Prevent microleakage/bacterial leakage which preserves tooth vitality (pulpitis)
- Confirm tooth prep is adequate
- Give occlusal stability (No OVD change and prevent drifting or tilting of prepared teeth)
- Preserve or improve function (mastication/speech)
- Isolation of RCT
- Matrix for core build up
What are the desirable materialistic characteristics of provisional restorations?
- Non irritant to pulp and periodontal tissues
- Low temp rise during setting
- Dimensionally stable
- Adequate working time
- Adequate setting time
- Adequate strength and wear resistance
- Good aesthetics
What are the types of Provisional restorations?
- Custom formed
- Preformed
What is a custom provisional restorations?
- Bespoke to individual situations
- Preferable
- Can be technically demanding
- Fits tooth prep internally
- Reproduces contact points and occlusion externally
What are preformed provisional restorations?
- Standard shapes and sizes
- May fit but most likely not
- Adjust to fit when on chairside
What material are custom provisional restorations made of?
- Usually chemical cured bis-acrylic composite resin
- Protemp plus
- Integrity Temp-Grip (Dentsply)
When are custom provisional restorations done?
- Made before impressions for definitive restorations are taken
- Help check tooth prep is satisfactory with no undercuts and sufficient reduction (use Svensen gauge)
How to check the degree of preparation?
- Use a Svensen gauge
- Once tooth prepared and constructed custom provisional restoration then can use the gauge
- Will show how much you have reduced the tooth so can show if you have underprepared the tooth
How are custom resin provisional restorations made?
- Do a sectional impression as a full arch impression is unneccessary and difficult to re-seat
- Use Addition cured silicone putty (president material)
- Can use Alginate or Softened modelling wax
- Alternative is Custom vacuum-formed plastic mould (stent) which is made on study model and/or diagnostic wax up in advance
Why do we use Addition cured silicone putty as the first choice for taking a custom resin provisional impression?
- Can be disinfected and kept by patient or clinician
- Can be reused so useful if problem with provisional restoration and new needs to be made
- Resistant to tearing
Why can alginate and Softened modelling wax be used for impressions of custom provisional but not the first choice?
Alginate
- Cheaper than addition cured silicone putty
- But cannot be reused or kept
Softened modelling wax
- Easy to adjust and smooth
- Cheap
- But unsuitable for deep undercuts
- It distorts
- Cannot be reused
What is the method for making custom resin provisional restoration?
- Sectional impression
- Prepare tooth for chosen restoration
- Syringe bis-acrylic composite resin material onto bracket table or mixing pad (ensure it is mixed and monitor the setting)
- Syringe material into sectional impression of tooth that has been prepared
- Relocate impression in mouth (ensure fully seated and ‘click’ over bulbosity of remaining teeth
- Remove before complete polymerisation (Rubbery and fully polymerised material difficult to remove from undercuts)
- Remove completely
- Remove flash and ledge (use highspeed or polishing discs)
What are some issues that can occur when removing the sectional impression from tooth?
May stay on tooth
- Gently ease off with instrument beneath contact points
- Otherwise it sets in undercuts
May be removed with the impression
- Leave to completely set
How can provisional restorations be useful in cases of tooth wear?
- Can be used to re-establish tooth shape
- Help pilot occlusion and aesthetics
Can provisional restorations be used for establishing anterior/incisal guidance?
- Use a diagnostic wax up
- Use articulated study models
- Ensure a FaceBow registration is done
- Then can produce crown for guidance
What are the lab instructions for the custom provisional restoration if you are changing guidance and occlusion?
- Study model and articulate cast
- Duplicate the waxed-up cast
- Construct vacuum-formed mould/stent/template
What does the Patient trial consists of?
- Wear until happy with form and function
- Adjust/alter and trim with bur, addition of composite, reassess
What is the method when making provisional crowns for tooth wear cases?
- Obtain mounted study casts
- Lab
- Produce diagnostic wax up
- Duplicate cast
- Construct vacuum stent over duplicate cast - Carry out tooth prep if required
- Use stent and provisional material to produce provisional restorations
- Patient wear Provisionals for trial period
- Reassess Aesthetics/ Occlusion
- If satisfactory then definitive restorations if not make alterations and reassess further
How can the guidance created for the Provisionals be used for the definitive restorations?
- Create a customised formed incisal guidance table
- Take impressions of provisionals in-situ and opposing teeth
- Mount casts on semi-adjustable articulator
- Place unset acrylic on incisal table
- Reproduce lateral and protrusive movements
- Use light cure to set the acrylic once done
- Definitive restorations now the same as provisional
What can you do if aesthetics need to be changed for provisional restorations
Minor change - Chairside using burs or addition of provisional material or composite
Extensive changes - Replace provisional restorations and go again with lab
What is an important soft tissue that is vital for aesthetics?
- Gingival contours important for aesthetics
- Can use provisional restorations to shape for gingival contours important for definitive restorations
What preformed provisional crowns are available?
Tooth coloured
- Polycarbonate (Directa)
- Clear plastic crown forms (filled with composite)
Metal
- Aluminium
- Stainless steel
- Different shaped/morphologies and sizes
What are some problems with preformed provisional crowns?
- Unlikely to fit accurately (Cervically/Occlusally/ Interdentally) - need to adjust
- Large bank of crowns needed to accomodate patients which is costly
When are preformed provisional crowns useful?
- Useful in situations where no impression taken prior to tooth preparation or damage
- E.g. trauma cases
What are the polycarbonate crowns (Directa, JS Dental Manufacturing Inc)?
- Available for 35+ years
- Tooth coloured shells
- Only for anteriors and premolars
What is the method for preformed provisional crowns?
- Select shell slightly larger than preparation
- Trim cervical aspect back until
- Correct prep dimension
- Seats fully over tooth prep
- Not bedding into gingivae (pink stone in straight handpiece)
- Fill shell with Trim or Protemp
- Seat over tooth
- Allow polymerisation
- Remove
- Check fit
- Trim/tidy if needed
- Cement using temporary luting cement e.g. Tempbond
- Cut off tag
** If overbuilt then blanching of gingivae occurs
What are clear plastic provisional restorations?
- Clear plastic crowns
- Thin and easy to trim with scissors
What is the method for clear plastic provisional restorations?
- Select and trim until fit
- Pierce hole at cusp tip/canine tip/incisal angle
- Air escapes
- No bubbles
- Fill with bis-acrylic composite resin
- Seat over tooth
- Allow setting
- Remove from tooth
- Remove plastic crown form
- Check margins and occlusion
- Adjust if necessary
- Cement with temporary cement
What are metal preformed crowns?
- Used for posterior teeth
- Can be aluminium or stainless steel
- Remove any ledges and sharp margins as this can cause soft tissue trauma
- Difficult to adjust but can use crimping device to help mould the margins
What can you do if you are replacing a old crown?
- Can use/modify original crown for temporary of new
- May need partially sectioned/relined
- Try and preserve original crown as much as poss
What instruments can be used to remove Old crowns?
- WAMkey
- Safe Relax/Anthrogyr
- Sliding hammer
What are preformed malleable composite crowns?
- Soft crowns, easily mouldable to tooth prep
- E.g. Protemp crown temporisation material
What is the method for Preformed malleable composite crown?
- Moulded over tooth to desired shape
- Partially light cured (2-3 secs Otherwise – difficult to remove)
- Remove then completely cure outside of mouth
- Check fit
- Adjust if necessary
- Cement
What are indirect provisional restorations?
- Lab made usually acrylic
- Low shrinkage intra-orally
- More accurate
- High strength
- Time and cost consuming
- Used long-term
Examples of used materials:
- Composite
- Acrylic
- Meta
What is conventional bridgework temporisation?
- Similar to custom-formed provisional crowns
- Diagnostic wax up of replacement tooth
Alternatives;
- Acrylic removable partial denture
- Essix retainer with pontic (prosthetic tooth)
- Edentulous space and only provisional crowns on prepared teeth
What advice should you give to patient after provisional restorations placed?
- Maintain good OH
- Brush 2-3X daily
- Interdentally 1-2X daily
- Caution with floss as may pull out provisional
What can bad OH lead to?
- Increased GCF
- Increased bleeding
- Poor moisture control for definitive impressions
- Inadequate cement lute placement
What happens if the provisional restorations is poorly fitted and poorly contoured?
- Patient is unable to clean it properly
- Can lead to caries
- Can lead to gingival inflammation
- Can lead to poor moisture control and gingival overgrowth which affects the master impressions and so affects final restoration
What should the provisional restoration have (characteristics)?
- Have good marginal fit
- Be well contoured e.g. no overhangs
- Cleansable and maintainable for patient for optimum home care
