Cavity Lining Materials
No description yet. This curated deck is ready for daily study.
Card preview (24)
what are some disadvantages of restorative materials?
• may not make intimate contact with the tooth surface • heat release during setting/curing • release of chemicals (pulpal irritants)
what is the function of a lining material used in conjunction with restorative materials?
• prevents gaps - acts as a protective barrier
what is the difference between a cavity base and a cavity lining?
Cavity base = thick mix placed in bulk (dentine replacement) Cavity lining = thin coating over exposed dentine
what is the purpose of a liner?
• pulpal protection • therapeutic/calm down inflammation within pulp • palliative to reduce patient symptoms prior to definitive treatment being carried out
what does a liner protect the pulp from?
• chemical stimuli in the filling material (initial pH of material also) • thermal stimuli (exothermic setting & heat conduction of materials) • bacteria and endotoxins (microleakage)
what are the ideal properties that should be seen in a lining material?
• easy to use (mix, long working time, short setting time) • low thermal conductivity • should match the thermal expansion coefficient of tooth • low thermal diffusivity • high compressive strength • similar modulus to dentine • radiopaque • LOW solubility • fluoride releasing/antibacterial • biocompatible
explain the ideal usage tendencies of a lining material that are desired?
• easy to mix • long working time • short setting time (command set ideal)
why is it important that the thermal conductivity of a lining material is low?
to prevent heat expelled from exothermic reactions/conduction of heat through metal materials irritating the pulp
what is meant by the thermal expansion coefficient of a material?
the change in length per uni length for a temperature rise of 1°C (ppm°c^-1)
what should the thermal expansion coefficient of a lining material be?
should try to match the thermal expansion coefficient of the tooth
what is the thermal expansion coefficient of enamel and dentine?
enamel = 8.3ppm°C^-1 dentine = 11.4ppm°C^-1
why is it important that lining materials have high compressive strength properties?
to allow placement of filling without it breaking
what is an example of a liner material?
setting calcium hydroxide
what is an example of a base material?
zinc oxide based cements
what is an example of a material that can be used as a cavity base OR liner??
glass ionomer & resin modified glass ionomer
what are the two main constitutes of setting calcium hydroxide liner?
base & catalyst
what is the setting calcium hydroxide liner base aspect composed of?
• calcium hydroxide • zinc oxide • zinc stearate • N-ethyl toluene sulphonamide
what is the setting calcium hydroxide liner catalyst aspect made up of?
• butylene glycol disalicylate • titanium dioxide • calcium sulphate • calcium tungstate
what is the setting reaction of a setting calcium hydroxide liner?
a CHELATION reaction between the ZnO and the butylene glycol disalicylate
what is the initial setting calcium hydroxide liner cement’s pH?
around 12
what are some positive properties of CaOH liner?
• quick setting time • radiopaque • easy to use
what are some negative properties of CaOH liners?
• low compressive strength - unstable and soluble (if cavity leaks then the lining will disappear)
what are some uses of Zinc Oxide Eugenol (ZOE) Cements and related materials?
• linings/base in deep cavity • temporary restorations • root canal sealer • periodontal dressings
what are some properties of zinc oxide eugenol?
• adequate working time • relatively rapid setting time • low thermal conductivity • low strength (20MPa) • radiopaque