7. Partial coverage restorations Flashcards
What is the purpose of a partial coverage restoration?
Used to reinforce remaining dental structure
What is considered a minimally invasive restoration?
Partial coverage restoration
What is an inlay?
without cusp covering
What is an onlay?
covering at least one cusp
What is an overlay?
Covers all cusps
What is the limitation of conventional partial coverage direct restorations?
Polymerization contraction
What are the consequences of light curing shrinkage or partial coverage direct restorations?
- gaps
- secondary decay
- crack propagation
- cusp fracture
- postop sensitivity
What are the factors influencing polymerization shrinkage? (4)
- cavity size
- cavity shape
- adhesive technique
- material application
What are the two phenomenas observed with light curing?
- light curing
- dark reaction
What is the light curing phenomenon ?
50% of polymerization when applying a light
What is the dark reaction phenomenon ?
10min-48 hours after light curing the material polymerizes to 100%
When is the ideal time to wait before polishing surfaces? (2)
- ideal: 48 hours
- wait 10 mins so polymerization reaches 75%
What should the distance between light and composite be?
1-2mm
What is the thickness reached by the light?
2mm
What is the emission spectrum of halogen? (2)
350-500nm
covers and cures 3 catalysers
What is the emission spectrum of plasma? (2)
460-480nm
only actives camphorquinone
What light curing unit is no longer used?
laser
What is the emission spectrum of LED 2nd generation?
430-490nm
only activates camphorquinone
What is the emission spectrum of LED 3rd generation?
- works with all different activators
- covers the whole spectrum
Emission spectrum of LED 3rd generation bluephase G2?
430-490nm
Emission spectrum of LED 3rd generation bluephase 2OI
430-490nm
Emission spectrum of LED 3rd generation valo cordless
395-480nm
What are the different types of partial coverage restorations?
Inlays
Onlays
Endocrown
What are the different types of onlays? (4)
- onlay
- overlay
- veneer onlay
- veneer overlay
Inlay vs direct composite filling?
inlay prep can be more aggressive
In lay controvery?
in class II MO/OD
What material can you use for inlays? (3)
- porcelain
- resins
- hybrid materials
When is an onlay indicated?
Big restoration with remaining axial surfaces
What material can be used for onlays? (3)
- Porcelains
- Resins
- Hybrid materials
What is a veneer onlay/overlay?
Same as a normal onlay/overlay but also covering the buccal surface
When do you use a veneer onlay/overlay?
For high aesthetic needs
What is an endocrown? (3)
- Full coverage cusp
- no post or pin
- for endo teeth
An endocrown uses the pulp chamber for… (2)
- more adhesive surface
- more macro-retention
What should you do if you have a small class I cavity?
Direct restoration
What should you do if you have a big class I cavity?
Direct restoration
What should you do if you have a small class II MO/OD cavity?
Direct restoration
What should you do if you have a big class II MO/OD cavity?
inlay/onlay/overlay
What should you do if you have a small class II MOD cavity?
Direct/inlay
What should you do if you have a big class II MOD cavity?
onlay/overlay
What should you do if you have a small destruction of a tooth?
Fiber post + overlay/endocrown
What should you do if you have a big destruction of a tooth?
Fiber post + overlay/endocrown
When is full coverage of cusps indicated? (3)
- parafunction
- upper endo premolars
- less than 2mm thickness of the wall
What are the prearation steps for partial coverage restorations?
- remove pathological tissue
- build up and relocation of margin if necessary
- preparing the cavity for the final restoration
What is the purpose of the build up preparation step for partial coverage restorations? (5)
- reducing the bur reduction
- eliminate retentive areas
- to lift the cavity floor
- create better access to the curing light
- strengthen cavity
What material do you use for the buildup in partial coverage restorations?
Nanohybrid composite
What occurs in the marginal relocalization step of partial coverage crowns?
- Elevating the margin of the prep
- during the build up step with nanohybrid composite
What are the indications of the marginal relocalization step of partial coverage crowns? (2)
- no good insulation possible
- good impression cant be taken
Partial coverage restorations: what does retention depend on?
ashesion
The shape of a partial coverage restoration should be..
Expulsive to have good adaptation of the restoration
Where is the adhesion in partial coverage restorations?
between internal surface of the tooth and external surface of the restoration
What is the minimal occlusal thickness for the restoration needed for partial coverage?
1.5mm
What is the thickness at the base of the cusp needed for partial coverage?
1.5-2mm otherwise remove
What is the thickness of the residual surfaces needed for partial coverage crowns?
2mm
What is the minimum width of the isthmus needed for partial coverage crowns?
2.5mm
The explsuive shape of the partial coverage restorations is good for…. (2)
Good insertion and settlement
The taper of the internal walls for partial coverage restorations should be…
6-10 degrees
___ mm of restorative material is needed in the cusps areas of partial coverage restos
2
Partial coverage restorations: The bigger distance with the adjacent tooth…
The bigger the interproximal box should be to recreate correctly the anatomy
What should you do when preparing partial coverage restorations and there are no remaining walls?
create indexes during the preparation and build up
Criteria for cavity approval for partial coverage restorations? (5)
• Detailed sharp margins
• Absence of undercuts
• Accessibility of subgingival margins
• Absence of contact between the cavity and the adjacent
teeth
• Adequate interocclusal space in centric and during lateral movements
How do you take impressions for partial coverage? (3)
- conventional with PVS
- putty + LBS
- antagonist needed for occlusion
Do you need a retraction cord for partial coverage restorations?
No, margins are supragingival
Why are provisionals for partial coverage restorations complicated?
Have no retention from the cavity
Why do we use provisionals in partial coverage restorations?
- protect the tooth
- avoid non-desirable movements
What is option A for partial coverage restoration provisionals? (6)
- Prepare a silicon key before the preparation
- With putty silicon
- Once we have the preparation and the impression
- Place Bis-acrylic resin into the needed area of the silicon key
- Place it into the mouth and wait for it dry
- We can gain some retention with one point of adhesive in the
middle of the preparation
What is option B for partial coverage restoration provisionals?
- Apply in the centre of the preparation one point of adhesive
- Shape a bulk of composite over the preparation
- Specific light curing materials exists for this specific restorations
- EX: Telio CS Inlay (ivoclar): used for provisional in class I and II
Which hybrid materials can be used for partial coverage restorations?
- Nanoceramic resin
- ceramic with resin
Characteristics of nanoceramic resin in partial coverage restorations ? (4)
- Resists chipping and cracking during the milling
- No post firing step needed
- High luster
- Easily abraded
Characteristics of ceramic with resin in partial coverage restorations ? (4)
- Ceramic strengthened by a polymer
- High load capacity after bonding
- High elasticity module
Vita enamic characteristics in partial coverage restorations? (4)
- More aesthetic b/c of its ceramic
- Composite filling suffers a high level of wear, resulting in exposition of ceramic crystals
- Creating a more abrasive restoration
- Requires fluorohydrique etching and silane
Lava ultimate characteristics in partial coverage restorations? (4)
- Pro: elastic modulus similar to the dentin
- Cons: high rates of wear, we
can loose easily our contacts
and guidance
Which material was removed for crown indications but remians to be indicated for partial coverage?
Lava ultimate restorative
What techniques are used to create partial coverage restorations? (3)
- layering
- milled
- pressing
Partial coverage restorations: layering technique? (2)
- Inherent errors similar as the direct technique
- The lab heat curing process provides better extraoral properties
Surface conditioning steps for cementation/bonding of partial coverage restorations?
- PREPARATION OF THE CAVITY
- DENTIN SEALING
- CAVITY BUILDING AND MARGINAL RELOCATING
- FINAL DENTAL PREPARATION
- ENAMEL CONDITIONING
- RESTORATION CONDITIONING
What kind of retention/adhesion is present in partial coverage restorations?
- micromechanical retention
- chemical adhesion
Partial coverage restorations: Steps for enamel conditioning?
- SELECTIVE ENAMEL ETCHING ORTOPHOSPHORIC ACID 37% 30 SEGS
- RINCE WITH WATER
- ABSOLUTE DRYING
- ADHESIVE (BONDING) -LAST STEP- BEFORE THE BONDING
Partial coverage restorations: Steps for dentin conditioning?
- needs isolation
- follow instructions
- more senstitive
- self etching adhesive in 2 steps
Pros of self etching adhesive in 2 steps for dentin conditioning of partial coverage restorations?
- less sensitive to the technique
- good results
Partial coverage restorations: Steps for composite conditioning?
- sandblasting to create micromechanical retention (aluminous oxide 30-50microns)
- Application of bonding that comes with the adhesive
Requirements for cement in partial coverage restorations? (6)
- Marginal fit
- Low solubility in the oral cavity
- Radioopacity
- Working time
- Viscosity
- Aesthetic properties
Types of resin cements used for partial coverage restorations? (3)
- microhybrid composites
- light curing resin cements
- dual curing cements
Describe the microhybrid cements used in partial coverage restorations
Heated up to 55 degrees
