Properties of a Lining Material Flashcards
what are the disadvantages of restorative materials?
may not make intimate contact with the tooth surface, heat released during setting/curing, release of chemicals
what is the solution for the disadvantages of restorative materials?
a lining material
what does a lining material do?
prevents gaps and act as a protective barrier
what is a cavity base?
thick mix placed in bulk, dentine replacement used to minimise the bulk of the material or block out undercuts
when are cavity bases used?
metal restorations
what is a cavity lining?
thin coating over exposed dentine
what is the purpose of a liner?
pulpal protection from chemical stimuli from unreacted chemicals in filler material, thermal stimuli from setting reactions/heat conduction, bacteria and endotoxins, therapeutic to calm down inflammation, palliative for reversible pulpitis
what are the properties of lining materials?
ease of use, thermal properties, mechanical properties, radiopaque, marginal seal, solubility, cariostatic, biocompatible, compatible with restorative materials
what should the length of working time be for cavity liners?
long to allow easy placement
what should the setting time be for cavity liners?
short and ideally command set
what should the thermal conductivity be?
low
what should the thermal expansion coefficient be?
similar to dentine
what should the thermal diffusivity be?
similar to dentine or lower
what is thermal conductivity?
how well heat energy is transferred through a material
what is thermal expansion coefficient?
change in length per unit length for a temperature rise of 1 degree celsius
what is the compressive strength of cavity liners?
high to allow placement of filling without breaking it
what is the advantage of radiopaque cavity liners?
makes it easier to see if there is any leakage or secondary caries
what type of bond is formed between the lining material and dentine?
chemical bond which should be permanent and impenetrable
what is the cariostatic properties of cavity lining materials?
fluoride releasing and antibacterial
comment on the biocompatibility of the cavity liner
non-toxic, not damaging to the pulp, low thermal conductivity
what are the types of cavity lining and base materials?
setting calcium hydroxide, zinc oxide based cements, glass ionomer and RMGI, palliative cements
