Provisional Extra Coronal Restorations Flashcards
when are provisional restorations provided
Provided between tooth preparation and fit of an indirect restoration
role of provisional restorations
Should be of high-quality - Otherwise, failures occur/ problems
- Role in immediate and long-term health of:
- Tooth
- Supporting structures (e.g. PDL)
- Definitive restoration – can shorten longevity
4 clinical stages in indirect restorations
- Preparation
- Temporisation
- Impressions and registrations
- Cementations
Success of each stage dependent on success of preceding stage
provisional restoration characteristics
- after tooth preparation
- aesthetics
- function - destabilises occlusion
- sensitivity - if exposed dentine
- good marginal fit
- be well contoured (no overhangs)
- cleansable and maintainable by pt - avoid plaque trap
poorly fitting and contoured provisional leads to
- Patient unable to clean
- Caries
- Gingival inflammation – can cause bleeding, harder to get clear margin on impression as bleeding over margin
- Poor moisture control
- Gingival overgrowth
provisonal resotration MUST (7)
- Establish and/or maintain dental aesthetics, mimicking either
- Original tooth
- Definitive restoration
- Prevent sensitivity
- Allow “optimum home care”
- Prevent plaque build-up and caries
- Maintain gingival health and contour
- Prevent microleakage/bacterial leakage
- Preserve tooth vitality
- Confirm that tooth preparation is adequate
- Occlusal reduction
- Intra- and extra-coronal design characteristics
- Occlusal stability
- No OVD changes (unless desired)
- Prevent drifting or tilting of prepared teeth into space created by prep
- Occlusal stability
- Preserve or improve function
- Mastication
- Speech
2 possible additional uses for provisonal restorations
- Isolation for RCT little tooth tissue left – hard to isolate, so place provisional so can use rubber dam for moisture isolation
- Matrix for core build-up
7 desirable characteristics of provisional materials
- Non-irritant
- Pulp
- Periodontal tissues
- Low temperature rise during setting high, expand on setting? wedge – cannot get off
- Dimensionally stable don’t want to take on fluid (expand) or shrink – clamp, looks
- Adequate working time
- Adequate setting time
- Adequate strength and wear resistance
- Good aesthetics
2 types of provisional restoration
custom formed
preformed
custom formed provisonal restorations
- “Bespoke” to individual situations
- Preferable – looks and fits better
- Can be technically demanding
preformed provisional restorations
- Standard shapes and sizes
- Adjust to fit chairside
custom resin provisional crowns material
- Chemically cured bis-acrylic composite resin
- Examples: Protemp Plus (3M ESPE); Integrity Temp-Grip (Dentsply)
benefits of custom resin provisional crowns
Customisable
- Fits tooth prep internally – fits snuggly
- Reproduces contact points and occlusion externally
- Can adjust – remove, add on
Make before impressions for definitive restoration are taken
- Helps check that tooth prep is satisfactory
- ? Undercuts
- Sufficient reduction
- Svensen gauge
why make provisional before taking impression for defintive restoration
- – not afterthought*
- Priority
- Ensure well-made and ready to go, impression and then cement*
- easier and smoother to run in clinic
type of pre op impression for extra coronal restorations
Sectional impression
- Full arch impression unnecessary
- Difficult to re-seat
3 potential materials for extra coronal restorations sectional pre op impressions
- addition cured silicone putty (e.g. President) best
- alginate
- softened modelling wax
addition cured silicone putty (President)
properties as pre op impression material
best for sectional impressions
- Can be disinfected and kept by patient or clinician (no shrinkage/expansion – useful if they lose temporary)
- Can be reused;
- Resistant to tearing
alginate
properties as pre op impression material
- Cheaper;
- Cannot be reused or kept – dries = shrinks; wet = expands – not dimensionally stable
softened modelling wax
properties as pre op impression material
- Easy to adjust and smooth;
- Cheap;
- Unsuitable for deep undercuts;
- Distorts;
- Cannot be reused
alternative to pre op sectional impression
custom vaccum-formed plastic mould (stent)
- Made on study model and/or diagnostic wax-up (need lab)
- Can pour direct on – look like existing teeth
- Or wax up so can be like final restoration
method of using custom resin provisional crowns
- Sectional impression
- Prepare tooth for chosen restoration
- Syringe bis-acrylic composite resin material onto bracket table or mixing pad
- Ensure its mixed and Monitor setting
- Syringe material into sectional impression of tooth that has been prepared
- Relocate impression in the mouth
- Ensure fully seated
- “click” over bulbosity of remaining teeth
- Remove before complete polymerisation
- “Rubbery”
- Fully polymerised material difficult to remove from undercuts
- Remove provisional completely
- May:
- Stay on tooth
- Gently ease off with instrument beneath the contact points
- Otherwise: sets in undercuts
- Be removed in the impression
- Stay on tooth
- Leave to completely set
- May:
- Remove flash and ledges
- High speed and/or polishing discs
- Confirm tooth preparation
- Svensen gauge
- Check marginal fit and occlusion in situ
- Adjust if required (ideally outside the mouth)
- Check aesthetics
- Cement provisional restoration
- Temporary luting cement
- E.g. TempBond NE (Kerr Dental) - Non-eugenol temporary cement material
- Trim away excess
- Margins
- Interdentally
- Dental floss
- Temporary luting cement
how fill should the pre-op sectional impression for the provisonal be with ProTemp
3/4 cusp
Sven gauge
check tooth prep and provisional thickness between its pincers
- Can check occlusal reduction is adequate for final prep
- Ensure not too thin – fracture
- High occlusal contact if lab make to correct width, need to trim down - fracture
when may occlusion be corrected with a provisonal stage
e.g. toothwear cases
Wax-up
- Duplicate Waxed-up cast
Construct stent over the top of wax-up
Make provisionals in stent
- Alterations? Yes – alginate impressions
Lab pour model of altered guide to make definitive
how can guidance made on provisionals be transformed to definitive restorations
Customised formed incisal guidance table created:
- 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
- Move maxilla (unlike true anatomy)
- Cure acrylic
- Remove cast and place cast (Master) that will make crowns on
- Check have same occlusal guidance with definitive
- Not too big – too much occlusal contact
- Too small – not enough contact
- Check have same occlusal guidance with definitive
diagnostic wax up purpose
- Satisfy patient’s aesthetic demands
- High aesthetic demand cases
- Alter provisional restorations
- Minor changes – chairside
- Burs
- Addition of provisional material or composite
- Minor changes – chairside
- Extensive changes
- Replace provisional restorations
- Alter provisional restorations
- Once satisfactory
- Make impression for technician
establishing gingival contours using provisionals
Use provisional restorations to achieve satisfactory emergence profile for definitive restoration
- mould gingiva around the tooth**
- e.g. bone level dental implants*
importance of establishing gingival contours (emergence profile)
- Want to look natural*
- mimic gingiva of adjacent teeth
- Mould to emergence profile – shape implant takes coming out of gingiva*
- Flat – collapse in - not aesthetic
- Want push gingiva out a bit to mimic natural contour*
- Add composite if flat, weeks away and back and gingiva remodel to look more natural
when are preformed provisional crowns useful
- situations where no impression taken prior to tooth preparation or damage
- E.g. trauma cases
polycarbonate crowns (directa)
Available for 35+ years
- Tooth coloured “shells”
- Tooth morphology
Anteriors and Pre-molars
- Sublined with acrylic, fill space with another acrylic – no voids
- E.g. Trim (PEMA temporary acrylic-resin)
method of placing a preformed polycarbonate provisional crowns
1. Select shell slightly larger than preparation
- Trim back until
- Correct preparation dimension
- Seats fully over tooth preparation - trial
- Not bedding into gingivae
- Pink stone in straight handpiece
- Fill shell
- Trim or Protemp
- Seat over tooth
- Allow polymerisation
- Remove
- Check fit
- Trim/Tidy if necessary
- Cement
- Temporary luting cement (e.g. Tempbond)
- Cut off tag with a bur
NOTE: If overbuilt – blanching of gingivae occurs
method of placing a preformed clear plastic provisional crown
- Select and trim until fit – marginal 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
preformed malleable composite crowns
E.g. Protemp Crown Temporisation Material)
Soft
- Easily mouldable to tooth preparation
Method
- Moulded over tooth to desired shape
- Partially light cured
- 2-3 secs
- Otherwise – difficult to remove as clamps too tight
- 2-3 secs
- Remove then completely cure outside of mouth
- Check fit
- Adjust if necessary
- Cement
composite as provisional restoration
- E.g. Veneer cases
- Spot bonded
provisonal replacement of missing teeth used for
Conventional bridgework temporisation
- Similar to custom-formed provisional crowns
- Diagnostic wax up of replacement tooth
Alternatives;
- Acrylic removable partial denture
- Essix retainer with pontic
- Edentulous space and only provisional crowns on prepared teeth
Resin-bonded bridges (minimal preparation) and implants
- Acrylic removable partial denture or Essix retainer with pontic
