Author:
sthomp88
ID:
78961
Filename:
Dental Materials
Updated:
2011-04-21 16:31:22
Tags:
Chapter sixteen
Folders:

Description:
week thirteen
Show Answers:

  1. Resins are __________ used for dentures, partial dentures, maxillofacial prosthetics, reline material, tissue conditioning, repair of prosthetics, denture teeth,
    polymers
  2. What are multiple "monomer" chemically bonded together, larger/longer chain molecules?
    polymer
  3. Polymerization is the act of forming polymers using _________ bonds
    carbon
  4. What are the 2 different types of polymerization?
    • addition
    • condensation
  5. What is the most common form of polymerization for dental materials, has three stages, and occurs when the free radical opens bond between carbon atoms of the monomer?
    addition polymerization
  6. What are the 3 different stages of the addition plymerization?
    • initiation
    • propagation
    • termination
  7. The polymerization process produces ___________
    HEAT
  8. What happens of the heat from polymerization is too high?
    it causes the monomor to vaporize causing porosity
  9. The combination of what two materials causes polymerization for acrylic resins (plastics)?
    liquid monomer mixed with small plymer powder
  10. The end product of polymerization of liquid monomer mixed with small polymer powder in acrylic resins (plastics); or the polymerized resin is called what?
    poly methyl methacrylate (PMMA)
  11. What are 3 sources of dimensional change of acrylic resins (plastics)?
    • polymerization shrinkage
    • water sorption
    • thermal expantion
  12. The coefficient of thermal expansion in acrylic resins is more than ________ that of composite resins
    twice
  13. Is the chemically cured or heat cured acrylic resin weaker, softer, more porous, and less color stable?
    chemically cured
  14. The chemically cured acrylic resin has more residual monomers than the heat cure, these residual monomers can cause what to tissues?
    inflammation
  15. acrylic resins that are chemically cured can undergo dimensional change in the first __________ hours
    12-24 hours
  16. What is it in polymerized acrylic resin that is characterized by the presence of many small or microscopic voids or pores?
    porosity
  17. What property of acrylic resins cause them to collect debris and microorganisms that give them stain and smell?
    porosity
  18. What is a result of loss of monomer or inadequate pressure during processing?
    porosity
  19. What property helps keep the monomer from evaporating during polymerization and creates a denser acrylic?
    PRESSURE
  20. At what pressure are acrylic monomers polymerized?
    in a pressure pot at about 15-20 lbs of air
  21. If acrylic resins are polymerized at 15-20 lbs of pressure it will result in what 3 positive characteristics for the acrylic resin?
    • denser acrylic
    • stronger acrylic
    • less porosity
  22. Acrylic resins polymerize by an ___________ reaction
    addition
  23. Acrylic resins that polymerize by an addition reaction are supplied as what 2 substances? What are each of them mostly made up of?
    • powder: PMMA (polymethyl methacrylate) and benzoyl peroxide (the initiator)
    • Liquid: mainly MMA (methylmethacrylate)
  24. Why is the liquid portion of the acrylic resin stored in dark brown bottles?
    to prevent ultraviolet light from initiating polymerization during storage
  25. Chemically cured liquid acrylic resins have ___________________ as an activator.
    tertiary amine
  26. Name and describe the 4 stages of chemically cured resins.
    • sandy stage: powder and liquid mixture; grainy
    • stringy stage: powder absorbs liquid into their surface
    • dough stage: more powder in solution
    • rubber stage: no longer can be manipulated
  27. In what type of resin cure does polymerization occur when liquid's tertiary amine activates the benzoyl peroxide in the powder; causing free radicals to develop?
    chemically cured resins
  28. chemically-cured resin polymerization is what type of reaction? (it produces heat)
    exothermic
  29. What is the most common method for processing denture bases?
    heat-cured resins: uses head and pressure during polymerization
  30. In the heat-cured polymerization of acrylic resins, heat activates, what which causes the formation of ree radicals and allows polymerization?
    benzoyl peroxide
  31. Polymerization shrinkage is the most evident in what part of the dentures?
    palatal area
  32. What is a problem with long term soft liners that may cause them to separate from the denture base at the edges and leak between the liner and the denture base?
    long-term soft liners do not form a good bond to the old acrylic
  33. Long-term soft liners can be made from one of what 2 substances that have been made pliable by the addition of PLASTICIZERS?
    • silicone rubber
    • acrylics
  34. The silicone liners for the use of long-term soft liners are more stable over the long term than the acrylic because they do not have softeners to leach out; however, they can be difficult to what?
    adjust
  35. Which type of long-term soft liner material support the growth of yeasts? What is a common yeast that may cause tissue irritation and requiring antifungal therapy?
    • silicone
    • candida albicans
  36. Which type of cure for the long-term soft liner has the best physical properties?
    laboratory heat-cured
  37. cleaning long term soft liners with what type of solution will help reduce the formation of yeasts?
    benzalkonium chloride
  38. Which type of denture liners are tissue conditioners, usually performed chairside, readapt to pts tissues under NORMAL occlusion; and are applied to primed denture base; reseated in the pts mouth for border molding?
    short-term soft liners (tissue conditioners)
  39. How long do short-term soft liners usually last?
    1-4 weeks
  40. Dentures become loose over time due to what?
    bony ridges resorbing
  41. Which type of hard liner must you be careful while performing because it causes an exothermic reaction and can burn the tissue?
    chairside reline
  42. which type of hard liner is heat and pressure processed?
    laboratory liner
  43. What are they two types of material used to make denture teeth?
    • plastic: acrylic resin
    • porcelain
  44. Which material of teeth used for denture teeth chemically bond to the acrylic base of the denture; and do NOT wear opposing natural or artificial teeth or restorations?
    Plastic: acrylic resin
  45. Are plastic (acrylic) teeth or porcelain teeth used for dentures softer and wear more rapidly, but don't stress bony ridges as much, and are more resilient?
    acrylic teeth: plastic
  46. Porcelain teeth do NOT bond to the denture acrylic and need what to hold them in?
    mechanical retention
  47. Porcelain teeth for dentures are contraindicated in what situation?
    if they are coming against natural teeth, they will wear them down
  48. Which type of denture teeth transmit heavier occlusal force which may cause pt discomfort, denture sores, and accelerate ridge resorption?
    porcelain
  49. What are 3 advantages of using porcelain denture teeth?
    • hard
    • esthetic
    • stain resistant
  50. a specialized aspect of a prosthodontic practice may include the fabrication of ________________ prosthesis to replace facial tissues, lost as the result of trauma, disease, surgery, or birth defects
    maxillofacial
  51. In which type of denture repair are the pieces held together by sticky wax during the repair; plaster or stone is poured around the prostheses for stabilization; cut fracture line with acrylic bur; wet and prime roughened with monomer like chair-side reline?
    chemical cured acrylic REPAIR material
  52. What are used to establixh the proper dimension between upper and lower arches for dentures?
    record bases
  53. In homecare for dentures, they should be cleaned with a denture brush with what material? (3)
    • liquid soap
    • mild hand soap
    • non-abrasive denture cleaner: some commercial denture cleansors are too abrasive
  54. Why is it important to rinse dentures thoroughly after meals?
    because they need to be cleaned of debris before being placed in a denture soak
  55. Calculus on dentures can often be softened by soaking it in what solution?
    1:1 ratio of water and white vinegar
  56. What solution should you absolutely NOT soak dentures in? Why?
    • undiluted household bleach
    • It will: fade color from acrylic
    • attack metal framework on partial dentures: metal will turn dark and corrode; NO commercial cleaner with bleach should be used for metal partials
  57. true or false. Calculus will accumulate on dentures in the same places as natural dentition
    true
  58. Where are the most common areas for calculus to develop on dentures?
    • maxillary molars
    • mandibular incisors
    • (same as natural dentition)
  59. Describe the 2 processes of cleaning calculus off of dentures at a DH appointment.
    • place in zippered bag with denture cleaning solution and place in ultrasonic cleaner
    • Carefully hand scale: polish with flour pumice, then tin oxide, or acrylic polishing compound
  60. How should acrylics be stored and why? Where should they NOT be stored and why?
    • stored in water to keep them wet: because acrylics hydrophobic and sensitive to water loss which may cause dimmensional change
    • Do NOT store dentures containing soft liners in mouthwash with alcohol: it may adversely affect the properties of the soft liner