Cements and Their Uses Flashcards
what are the types of cements
-zinc phosphate
-zinc oxide eugenol
- zinc polycarboxylate
-glass ionomer
- resin modified glass ionomer
- provisional cements
cement will not perform to its optimal level clinically without an ___
adequate preparation that includes good resistance and retention form
what are the different properties of cements
-biocompatibility
-retention
- mechanical properties
- marginal seal
- low film thickness
-ease of use
-radiopacity
-esthetics
what are the mechanical properties of cements
withstand occlusal forces, high tensile strength
what is the gold standards of cements
zinc phosphate
what are the advantages and disadvantages to zinc phosphate
-advantages: thin film thickness and proven reliability, low solubility which resists breakdown in the mouth, low thermo conductivity, provides less sensitivity to hot and cold, long shelf life
- disadvantages: initial low pH which can lead to pulpal irritation, no chemical adhesion/bond, no antibacterial properties, poor esthetics, long setting time of 2.5-8 minutes, exothermic
describe type 1 zinc oxide eugenol
-less strong and is used for temporary restorations and for temporary cementation
-temp-bond
describe type 2 zinc oxide eugenol
-reinforced and is stronger
-referred to as an intermediate restorative
-can last for 6-12 months in the mouth
-used for a tooth that cannot be restored immediately (IRM)
what are benefits of zinc oxide eugenol
-neutral pH
- has a sedative or soothing effect on the dental pulp
- protective or insulating base of liner is not required
what is zinc oxide eugenol not used under and why
-not used under composite or acrylic restorations because it is incompatible with these materials and retards their setting process
what do the type and intended use of zinc oxide eugenol determine
whether the powder is incorporated into the liquid in increments or all at once
what is the mixing time for zinc oxide eugenol
30-60 seconds
what is the setting time for zinc oxide eugenol
3-5 minutes
what is the first cementing system to obtain an adhesive agent that bonds to enamel and dentin
zinc polycarboxylate
what are the characteristics of zinc polycarboxylate
-antibacterial action
- shorter working time of 2-5 minutes
- needs to be mixed quickly 30-40 seconds
describe the characteristics of polycarboxylate
- powder incorporated in large quantities
- it is not as fragile as zinc phosphate
- can have poor marginal sealing due to film thickness
-sometimes doesnt support occlusal stress as well as newer cements - will bond to most allows but not to gold
- due to its potential for plastic deformation, it is much more difficult to remove excess cement
- although bonds well to enamel/dentin its use has lessened over the years
what is another name for glass ionomer
acid base cement
what is part of the success of glass ionomer cements
their performance is good even if they have not been properly mixed
what are the characteristics of glass ionomer
-very thin film thickness
-extremely moisture tolerant but fairly soluble
-fluoride release that can be sustained for long periods of time
-protects the tooth/margins from further tooth decay
- radiopaque
describe fluoride release in glass ionomer
initial rapid release followed by a sustained lower level diffusion release
when is fluoride released by a glass ionomers
in acidic conditions and will increase the pH to buffer
what are the uses for glass ionomer
liner, luting agent, build up material, contain silver particles for strength
what are the characteristics of resin modified glass ionomers
-added hydrophillic methyacrylate monomers
-acid base cement
-all the same benefits/advantages of glass ionomer cements
- disadvantages: low early strength and moisture sensitivity during setting
how long does it take for resin modified glass ionomers to fully set
24 hours
