Luting cements Flashcards
What is a luting cement? π§ͺ
A luting cement is a dental material used in a paste form that undergoes a setting reaction to become a solid, forming a bond between a prosthesis and tooth.
What does a luting cement bond together? π
It bonds tooth tissue (enamel/dentin) to restorations such as metal, porcelain, or composite.
What are the roles of dental cements? π§±
Seal interface between tooth and restoration π§©
Prevent bacterial microleakage π¦
Provide mechanical, chemical or combined adhesion
Maintain retention and integrity of the restoration
What is the general cementation procedure? π οΈ
Isolate and dry preparation π¨
Clean and dry restoration π§Ό
Mix cement π¨
Apply thin layer in restoration
Seat restoration firmly and apply pressure πͺ
What are the biological properties of an ideal luting cement? π§«
Biocompatibility π§¬
Non-toxic β οΈ
Low allergenic potential π€§
Inhibits caries/plaque π¦·
Prevents microleakage π
What are aesthetic properties of ideal luting cements? π¨
Colour stability π
Radiopacity β’οΈ
What are ideal working properties? β±οΈ
Low film thickness (~25ΞΌm) for better fit
Appropriate viscosity for flow π
Small particle size β smooth flow π
Why is no single cement ideal for all situations? π€·
Because different restorations and clinical situations require different properties. Therefore, multiple materials are used in practice.
What are common failure mechanisms? π₯
Cement microfractures
Microleakage β bacterial ingress
Catastrophic restoration failure
How does Zinc Phosphate set?
Acid-base reaction between ZnO + MgO powder and phosphoric acid liquid.
Does Zinc Phosphate bond chemically to tooth?
β No, it provides mechanical retention only.
Zinc Phosphate
Q12: Strengths and properties?
Compressive: 80β100 MPa
Tensile: 5β7 MPa
Stiff cement, Modulus: 13 GPa
Film thickness: <25ΞΌm
How does GIC set?
Acid-base reaction between fluoroaluminosilicate glass and polyalkenoic acid.
GIC key properties
Adheres to tooth structure
Reduces microleakage
Compressive strength: 90β230 MPa
Resin-Modified Glass Ionomer (RMGIC)
What are its setting reactions?
Acid-base reaction
Free radical polymerisation of methacrylate groups (no light needed)
Benefits & limitations of RMGIC
β
Bonds to enamel/dentin, releases fluoride, better strength than GIC
β Hygroscopic expansion, not suitable for feldspathic ceramics, free monomer risk
Resin Composite Cements
Q17: Composition and setting?
A: Bis-GMA + methacrylates, set by photo/chemical polymerisation
Resin Composite Cements advantages ?
Strong bond to etched enamel/dentin
Bonds to resin, silane-treated porcelain, metals
High compressive strength πͺ
High aesthetics π¨
Insoluble in oral fluids π
Limitations of Resin composite cements?
β Polymerisation shrinkage β gap formation
β Technique sensitive
β Air inhibited
β Eugenol cements contraindicated beforehand
What are some popular commercial luting cements?
RelyXβ’: Dual-cure, self-adhesive resin cement
GC FujiCEM: Paste-paste RMGIC, high bond strength, low film thickness
SuperBond 4-META: Bonds strongly to metals via oxide layer interaction
Panavia: Contains MDP monomer for strong adhesion, water-resistant
What are key bonding interactions for luting agents?
Enamel/dentin β Resin
Resin β Composite
Silane β Porcelain
Resin β Silane
Resin β Metal
Composite β Tooth
Self-adhesive cements work via which 2 mechanisms?
Self-etching: Forms micromechanical bond before polymerisation
Secondary chemical bond: Via reaction between acid and filler in water β GIC-like bond
Match the restoration to its ideal cement:
Cast metal, PFM, crown, onlay β
Resin bonded FPD β
Tooth-coloured inlay / veneer / silica-based ACC β
High strength all-ceramic crown
Cast metal, PFM, crown, onlay β Composite / RMGIC
Resin bonded FPD β Composite resin
Tooth-coloured inlay / veneer / silica-based ACC β Composite resin
High strength all-ceramic crown β RMGIC or GIC
Final summary of ideal luting cement features? β
Must not harm pulp or tissues βπ§
Adequate working time β³
Low film thickness for full seating π
Sets into a strong, durable mass πͺ
Moisture-tolerant and biocompatible
