Dental Materials Test 1
Terms
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- Fluoride, Pit & fissure sealants
- How can dental caries be eradicated by the use of preventive dental materials?
- for: good OH, deep pits against: bad OH, no caries, no pits, interproximal decay
- What are the indications & contraindications for dental sealants?
- Makes microscopic holes (enamel tags) for bonding
- What does conditioning or acid etching accomplish?
- 1. coarse & etch 2. rinse 3. dry w/ air 4. apply sealants 5. polymerize with light 6. finishing
- What are the basic sequential steps in placing a pit & fissure sealant?
- Decrease gagging, decrease irritation, decrease speech impediment, increase compliance
- List the advantages of a custom made mouth protector
- the shrinking or enlargement of dental restorations caused by changes in temperature
- what is percolation?
- possible irritation to the dental pulp & recurrent decay
- What are the harmful effects of percolation?
- Different CTE's between tooth and restoration or between restorative materials
- What causes percolation?
- the product met established criteria of the appropriate program & terms of labeling, advertising & promotion are clean & accurate & valid & comply with advertising & exhibiting standards of the ADA
- ADA seal means
- 2 metals corrode/react with each other: the dissolution of metals in the mouth (can result when adjacent restorations are dissimilar metals)
- Corrosion
- solid when standing, easily flows when stirred
- thixotropic
- because its pH is between 6 & 8 so it minimized acid etching of restorative materials (more so than APF)
- NaF is used in mouths with numerous restorations. why?
- MB: penetration of a liquid into very small surface pores & irregularities btwn the 2 surfaces being bonded-they are not fused as one. Adhesion: atoms & molecules are actually held together by some type of attractive force. Substances actually become one. It is the force that actually causes unlike atoms & molecules to attach to each other
- Difference between mechanical bonding & adhesion
- patients with poor hygiene, teeth with no pits & fissures, teeth that have been caries free for a long time, teeth with many proximal lesions
- situations when sealants shouldn't be used
- permanent deformation under tensile stress without fracture (stretch w/ out breaking)
- ductility
- the study of the flow of liquids
- rheology
- the characteristic of color looking different in different light
- metamerism
- refers to the hardness which is the "resistance of a solid to penetration" the harder the substance you use, the more likely it will withstand abrasion
- abrasion resistance
- continuing deformation
- flow
- resistance of a liquid to flow
- viscosity
- the resistance of a solid to penetration
- hardness
- measurement of the changes of a tooth or restorative material when exposed to temperature changes in the mouth
- CTE (coefficient of thermal expansion)
- greatest stress a structure can withstand without breaking
- Ultimate Strength
- No mix: one component system, sealants polymerize with visible light Mix: two component system, polymerize without light, polymerize with organic component. the 2 are mixed before applied to prepared tooth
- Explain Mix and No Mix sealants
- amalgam & gold inlay
- posterior teeth with high biting forces are restored with:
- high strength and high wear resistance
- restoration of a posterior tooth has
- zince phosphate, composite plastics
- which have thermal conduction similar to enamel & dentin?
- low surface energy of liquid & high surface energy of solid, surface irregularities, air pockets & debris all decrease the wetting ability
- which factors increase wetting of a solid?
- solid, liquid, gas
- states of matter
- H3PO4 (orthophosphoric acid)
- acid used today to etch enamel?
- enamel and dentin aren't homogenous, surface of prepared tooth has many irregularities, smear layer, moisture is present
- why is adhesion difficult in the mouth?
- static forces are applied at a fixed rate of speed or time. dynamic forces are applied extremely quickly
- difference in dynamic and static:
- the property of a fluid that resists the force tending to cause the fluid to flow
- viscosity
- soften w/ heat, harden w/ cooling
- thermoplastics
- increase wetting of a solid
- decrease surface energy of liquids
- increase wetting of a solid
- increase surface energy of solids