Inlays and Onlays Flashcards
What is an inlay?
Intracoronal restorations made indirectly to strengthen and repair decayed or damaged posterior teeth
How are inlays and onlays different?
Onlays extend over weakened cusps to provide extra protection
Why were early ceramic inlays not very successful?
Marginal integrity issues
No bond between restorative material and tooth tissue possible
Luting cement washed out of marginal discrepancies
Discolouration, marginal openings and 2ndry caries
More aggressive to opposing dentition
What are the indications for inlays and onlays?
As an alternative to amalgam
- Amalgam toxicity concerns
- Lichenoid reactions
When resin composite not indicated
- Size of cavity
- Previously failed composite restorations
- Aesthetics
When long lasting aesthetic result aimed
Conservative type of indirect restoration
Indications for onlays?
Teeth with larger restorations, but sound buccal and lingual walls
- Endodontically treated teeth
- Wider MODs
- MODs in premolars
Indications for inlays?
Low caries rate
Small MO or DO cavities in molars and premolars
Conservative MOD in molars
Contraindications to inlays and onlays?
Poor OH
Pt with excessive occlusal loading e.g. bruxism
What materials are used for inlays and onlays?
Gold
Ceramic
Resin composite
Advantages of inlays and onlays?
Conservative Marginal integrity Good wear Corrosion resistant Relative ease of handling Excellent physical and mechanical characteristics Excellent survival rates (25-40yrs)
What to consider with inlays and onlays?
Cost
Technique sensitivity - clinical and laboratory
Poor aesthetics
Wedge effect of inlay
Advantages of adhesive technologies (e.g. composite)?
Aesthetic restorations
Stronger and more stable material (no wear; discolouration)
Marginal leakage due to polymerisation shrinkage is minimal
Conservative ceramic restorations
What to consider with adhesive technologies?
Ceramic = fragile = handle with care
Sensitive technique
- Intraoral adjustment contraindicated until restoration is bonded
- After bonding, adjustments can compromised aesthetics
- When bonded certain stages are required to guarantee the result
Bonding indirect composite is a problem
Wear of the luting agent can lead to marginal gaps and 2ndry caries
Longer tx: indirect restorations - 2 visits unless CAD/CAM used
Cost
What are the types of ceramic?
Feldspathic glass ceramic
Leucite reinforced ceramic
Lithium disilicate ceramic
Types of indirect resin composite?
Hybrid composite
Ceromers
Ceramic optimised resins
Paradigm MZ100 (3M ESPE)
BelleGlass (Kerr)
Targis (Ivoclar)
Fabrication techniques for gold inlays/onlays?
Lab made - lost wax, casting
Fabrication techniques for resin composite indirect inlay/onlay?
Chairside technique - CAD/CAM, imp technique (direct/indirect)
Fabrication techniques for ceramic inlays/onlays?
Conventional techniques (Pressable, refractory investment techniques, cast ceramic), CAD/CAM (lab made, chairside)
Preparation for inlays/onlays?
Box shaped cavities
Divergent walls to allow path of insertion
No undercuts
Limit path of insertion
Resistance to occlusal forces
Specific guidelines for gold/ceramic/composite inlays and onlays
Requirements for gold inlays?
2mm occlusal reduction
Proximal box 1mm width
Isthmus 1/3 of intercuspal width
Requirements for gold onlays?
Intracoronal prep same as inlay
1.5-2mm cuspal reduction
1mm occlusal shoulder
Preparation for ceramic inlays?
Similar to gold inlay but no bevels
Box shaped cavity
Parallel and slightly divergent walls
Round internal line angles
90 degree to CSA
2mm deep occlusally
No grooves or slots as restoration will be bonded
Beveled finishing lines can create thin areas of ceramic - may fracture during cementation
Check occlusal contacts
Outline of cavity should avoid occlusal contacts to avoid unnecessary loading on margins that could lead to deterioration of cement and marginal openings
Preparation for ceramic onlay?
Same as inlay
One or more cusps prepared
Different preparation guidelines for cusp reduction
Important features of ceramic onlay/inlay prep?
Check occlusal contacts
Outline of cavity should avoid occlusal contacts = avoids unnecessary load to the margins - lead to deterioration of cement and marginal openings
Undercuts blocked with GIC, RMGIC, resin composite
Armamentarium = Basic dental setup for restorative (inlay/onlay) procedures, what is needed?
Burs: medium grit tapered and straight diamond burs
Special bur kits - give box shaped cavities
Retraction cord and packer or gingival retraction paste
Provisional material e.g. protemp
Features of direct temporisation?
Composite based temporary material e.g. systemp Use as other temp filling materials Shape with flat plastic instruments No impression required No temp cement
Features of indirect temporisation?
Pre-op impression required or lab made vacuform shell
Self curing acrylic material
Composite based acrylic material e.g. protemp
TempBond NE to cement
Requirements for cementation?
When adhesive cement is used it should be performed under rubber dam
What is used for the cementation of gold restorations?
Traditional cements - GIC, zinc phosphate
Resin cements - Panavia, Rely X
Cementation of aesthetic inlays onlays?
Resin luting agents preferred
Self cured or dual cured resin composite cement
Compomers are contraindicated due to expansion = fracture of ceramic
How do glass ceramics work?
Fitting surface treated with HF acid or sandblasting
Coating of fitting surface with a silane coupling agent
Resin cement for the cementation:
- Calibra
- RelyX unicem
- Nexus
Bond between ceramic and tooth is created
Restoration and tooth will act as one piece
How do composites work?
Roughening of fitting surface with diamond burs or sandblasting is NOT sufficient
Resin cement for cementation
Bond of composite cement to composite inlays still exist as a problem
Failure of composite - composite bond (60% marginal opening in 6 months)
How does cementation work?
High viscosity resin composite material can be used
Thickness of the ceramic should not exceed 2mm to ensure adequate curing
Colour of inlay can affect the setting of the material and may need to increase light curing for darker shades
