Dental cements Flashcards
process of attaching one structure to another w/ use of intermediate agents like cement
-prosthesis are attached to teeth
luting
- to protect pulp
- therapeutic like stimulation of secondary dentin formation
liner
- thicker/stronger than liner
- thermal insulation
- condensation forces
base
a very thin layer applied on wall of cavity including margins
- prevents chemical irritants from entering pulp
- prevent initial microleakage
varnish
Classification
- based on application:
- temporary cementation-zinc oxide eugenol
- permanent
- based on composition
cements for pupal protection
- calcium hydroxide
- ZOE cement
Types of cement
- Silicate
- Zinc silicophosphate
- zinc phosphate (zinc cement)
zinc phosphate cement
commercial names: de Trey, Harvard cement
-classification
- powder:yellowish/cream color
- liquid: clear
- Type 1: luting cement film thickness 25um<
- typeII: all other use 40 um
Zinc phosphate cement
powder compostion
- zinc oxide
- magnesium oxide (to reduce temp of calcination process)
- silicone dioxide aids in calcination
- bismuth trioxide-imparts smoothness
- stannous fluoride
zinc phosphate
liquid
- phosphoric acid
- aluminum, zinc, their compounds: help in partial neutralization of the acid to reduce the reactivity. est smooth, nongranular, workable cement mass during mixing
zinc phosphate
chemistry of setting
- zinc oxide + phosphoric acid -> zince phosphate
- zinc phosphate + aluminum (in liquid)-> zincealuminophosphate gel
zinc phosphate
consistency of mix
- luting consistency: fluid, glossy, stringed up
- base/filling: appears dull, thick, formed into rope
- mixing time: 60-90sec
- setting: 5-9min
zinc phosphate
mechanical properties
- compressive strength
- tensile strength
- Influenced by:
- initial powder and liquid comp/ratio
- method of mixing
- handling of cement during placemnet
copper cements
- similar to zinc phosphate, contain zinc oxide and phosphoric acid
- antibac effects
- black’s copper cement containing cupric oxide
- used in temporary restorations in pedodontic patients
- irritant to pulp
zinc silico phosphate
-fluorothin, kryptex
- powder: pigmented opalescent powder
- silicate glass in high zinc oxide powder
- liquid: clear, 50% phosphoric acid
- water
- aluminum/mercuric chloride
zinc silicophosphate
properties
- doesn’t bond to tooth structure
- sim to zinc phosphate
- solubility to water high
- contains fluoride for release
- translucent
- manipulation:
- powder incorporated in in 2-3 increments, mixing time <1min
- use: porcelain jacket crown
- filling deciduous teeth
- die material
- ortho brackets
zinc silicophosphate
advantage
disadvantage
- high strength, anticariogenic, translucent
- high initial pH
silicate cement
biotrey, silcap
Powder
- silica and alumina
- fluorides
- calcium phosphate
silicate cement
liquid
- phosphoric acid
- aluminum silicate
- zinc phosphate
- water
silicate cement
- advantage
- disadvantage
- high compressive strength
- anticariogenic property:fluoride is released to prevent caries in adj toothstructure
- esthetics
- high pH, injurious to pulp
- tends to stain
- high solubility
