Zusammenfassung der Ressource
DENTAL MATERIAL
- DENTAL COMPOSITES: fill material and sp tray
- Consits of: RESIN, FILLER, COUPLING AGENT
- FIBRE REINFORCED MATERIALS:type of composite
- consits of: FIBRES OF HIGH STRENGTH AND MODULUS
- EMBEDDED IN A BONDED MATRIX
- TESTS USED TO CHARACTERISE MATERIALS
- TENSILE = for applied to elongate rod
- COMPRESSIVE = force applied, not recommended for brittle materials
- DIAMETRAL TENSILE STRENGTH = for brittle mat where conventional tensile n/a
- FLEXURAL = determines how material bends (3points)
- VICKERS,BRINELL,KNOOP = surface hardness test
- Large num - low hardness, small num - high hardness
- SHEAR BOND STRENGTH = adhesive failure. Pebdulum swing #'s specimen
- SURFACE ROUGHNESS = Profilometer asses surface characteristics
- THERMAL PROPERTIES = thermal conductivity (K) rate of heat transfer
- RHEOLOGICAL PROPERTIES
- Study of the flow of materials
- ie Luting cement , flowable comp
- Study of VISCOSITY and how it vaaries with rate of shear and time
- DILATANT: viscosity INCREASES with applied pressure
- NEWTONIAN: viscosity remains CONSTANT with applied pressure
- PSEUDOPLASTIC= viscosity DECREASES with applied pressure
- CHEMICAL PROPERTIES - CORROSION
- Chemical reactivity of metals and alloys
- An electrolytic property
- Should dispaly good corrosion resistance
- BIOLOGICAL PROPERTIES
- lab screening, in vivo test, human randomised cotrolled trial
- Ideal material - non toxic, non irritant to the pulp, non cariogenic