Composites Flashcards
- Understand the rationale for the production of metal-ceramic restorations
metal - M- good mechanical properties
ceramic - BCE - esthetics and wear performance
esthetic, strong/hard, tough
- Describe the nature of ceramo-metallic bonding
Need
- Micromechanical Bonding (microabrasions on surface of alloy contribute to this)
- Chemical bonding (oxides in ceramic bond to oxide in alloy)
- Define veneers
thin, semi translucent “shell” custom made to fit over the existing tooth - made from porcelain. very brittle on its own but when bonded securely to enamel it is strong, tough and durable
- List the dental circumstances for which veneers have been claimed to be beneficial
closing spaces in teeth, restoring chipped teeth, whitening permanently stained, correcting uneven teeth
- Describe the nature of bonding of veneers to enamel
held in place by adhesive resin. bonded to tooth enamel. veneer is permanently bonded and is extremely strong and durable
- List the merits of veneers
very conservative (little or no tooth removal) esthetics
- Define composite materials
composite MATERIAL is where a constituent is added to the material to enhance its properties
ex resin-based dental composites
mainly polymer/ceramic combos
- List the general constituents of dental resin composites
- *dimethacrylate polymers
* *inorganic fillers
- Discuss the function of dimethacrylate resins in dental resin composites
give rigid material and TOUGHNESS
- List the types of fillers in dental composites
silica, barium glass, zirconia/silica (strength and wear resistance)
- State the purpose of the coupling agent in dental composites
*** BONDING.
to covalently link the polymeric resin to the ceramic fillers. bonds polymer and filler to provide reinforcement
- State the conditions required to achieve polymer reinforcement
- adhesion btwn polymer and filler
- filler should be more rigid (higher mod) than polymer
- filler can act as load bearing component
- State the effect of particulate inorganic fillers on dental composites
improve compressive strength
increase hardness
less setting shrinkage
define composite
when complementary substances (metal, ceramic, glass, polymers) combine to produce structural and functional properties NOT present in any individual component. theyre better together than they are as individuals :’)
one of two themes for composites - composite where separate materials are bonded together (2)
- metal ceramic restorations
2. veneers
