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
ProTemp is
bis-acrylic composite resin
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 to remove excess cement
when fully set
probe will break away excess cleanly when set
basic role of provisional in terms of occlusion
- Want to mimic final restoration*
- Want to establish OVD or guidance (canine ideal, or group)*
why do we want provisional to mimic definitive restoration
pt view
Allows pt to provide input – easier to change things at provisional stage before the definitive made
how can a provisoinal help establish occlusion and aesthetics
- Loss of original tooth form (e.g. wear cases)
- Re-establish tooth shape
- Pilot occlusion and aesthetics using provisional restorations
- Won’t look as good as final – poorer materials
- Guidance (anterior/incisal)
- Produce on crowns
- Diagnostic wax up
- Articulated study models
- Needs to be mounted
- FaceBow registration required
- Anything that involves guidance or redesigning an occlusal scheme
- Produce on crowns
stages once guidance and aesthetics of provisional satisfactory
- Lab
- Duplicate waxed-up cast
- Construct vacuum-formed mould/stent/template
- Back to clinic
- Next patient visit
- Prepare teeth
- Use mould to produce custom-formed provisional restorations to new occlusion and appearance
- patient trial
- Wear until happy with:
- Function
- Form – too thin, bulky
- Adjust/alter
- Trim with bur – high occlusal
- Addition of composite – missing occlusion
- Wear until happy with:
why is there a pt trial period with provisional restorations?
- Can alter provisional easily until both clinician and pt happy with form and function*
- use mould/stent from lab to construct a custom-formed provisonal restoration of new occlusion and appearnce
no alterations made to provisonal of new occlusion
no need for more impressions
alterations made to custom formed provisional
need to take more records for lab
new impressions with altered provisonals in situ
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
how to check definitive restorations have same occlusion as provisonals
Master cast mounted on articulator
Technician constructs definitive restorations
- Constantly checks again excursive movements
- Guided by custom-formed incisal table
- Simultaneous contact between restorations/opposing teeth and incisal pin/guidance table
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
preformed provisonal crowns variations
tooth coloured
- polycarbonate (directa)
- clear plastic crown forms (fill with composite)
metal
- aluminium
- stainless steel
problems with preformed provisional crowns
- Unlikely to fit accurately
- Cervically
- Occlusally
- Interdentally - shy, bulbous
- Large bank of crowns needed
- Accommodate variation between patients
- Costly
- Accommodate variation between patients
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
clear plastic preformed crowns - good as
thin
so can trim with scissors
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
metal preformed crowns uses
more for paeds
Used for posterior teeth
Materials:
- Aluminium
- Stainless steel
Any ledges and sharp margins
- Soft tissue trauma – careful when placing as bleeding affect final impression
Difficult to adjust
- Some provided with crimping device to help mould margins
if there is an old crown in situ but needs replacing
Can use/modify original crown for temporary
- May need partially sectioned/relined
- Preserve original crown as much as possible
Removal
- WAMkey
- Safe Relax/Anthrogyr
- Sliding hammer
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
indirect provisional restorations
Lab made
- Low shrinkage intra-orally
- More accurate
- High strength – compared to composite
- Time and cost consuming – more visits, more lab
- Used long-term e.g. full mouth rehabilitation due to large tooth wear – can be in Provisionals for 6 months so want them to last
Examples of used materials:
- Composite
- Acrylic (usual)
- Meta
examples of materials used in indirect provisional restorations
Composite
Acrylic (usual)
Meta
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
pt advice when provisonal in place
- Patient to maintain good OH
- Brushing 2-3x daily
- Interdentally cleaning 1-2x daily
- CAUTION WITH FLOSS - May pull out provisional restoration
- Pull floss out in forward/buccal direction rather than down
- CAUTION WITH FLOSS - May pull out provisional restoration
if pt doesn’t maintain good OH when provisonal in place
Gingival inflammation
- Increased:
- GCF
- Bleeding
- Poor moisture control for definitive impressions
- Inadequate cement lute placement
importance of custom formed restorations in tx
- Important for planning changes
- Aesthetics
- Occlusion
summary
provisional restorations need
characteristics of definitive restorations
act as a marker for dentist
- tooth prep
- errors
