Author:
sthomp88
ID:
66840
Filename:
Dental Materials
Updated:
2011-03-25 00:36:49
Tags:
Chapter seven
Folders:

Description:
week five
Show Answers:

  1. What is the purpose of a sealant?
    to prevent dental caries in pits and fissures of deciduous and permanent teeth
  2. The greatest benefit from fluorides has been seen on ______ _______ surfaces
    smooth enamel
  3. most caries (about 88%) in children are found where?
    in pits and fissures
  4. treatment of carious teeth with ENAMEL sealants resulted in an ________% reversal from a caries-active to a caries in-active state
    89
  5. true or false. Because some individuals will remain caries-free throughout their life-time, it is not indicated to seal all posterior teeth. The dentisth should use their linical judgment based on specific criteria to determine which teeth should be sealed
    true
  6. approximately ___% of caries in primary teeth occur in the pits and fissures of the molars
    44
  7. Why do permanent molars decay 3-4 times more frequently than premolars?
    because of th emore complex occlusal morphology
  8. Which permanent teeth are the most susceptible to pit and fissure caries?
    mandibular first and second molars
  9. Sealants are most commonly lost from what teeth? And why?
    • permanent 2nd molars
    • moisture contamination
  10. true or false. sealants are chemically similar to composite restorations
    true
  11. The resin component of sealants is based on a dimethacrylate monomer that is either one of what 2 substances?
    • A-glycidyl methacrylate (bis-GMA)
    • urethane dimethacrylate (UDMA)
  12. What are 2 ways that polymerization of the resin in sealants occurs?
    • soley by chemical reaction (self-cure) by conventional peroxide-amine system
    • light activation (light-cure) blue light polymerizes them
  13. What type of cure leaves oxygen inhibited layer on the surface that does notpolymerize, and oxygen in the airinhibits set of resin on surface sealant?
    light cure (one component system with activation light)
  14. Why doesn't sealant material have as many filler particles as some others?
    the less filler particles, the less viscous, they would be too viscous to flow into narrow fissures
  15. In which type of set does it require the mixing of two agents?
    self-cure
  16. the self-cured sealant polymerizes to final set within about _________ from the start of mixing the two components.
    2 minutes
  17. What technique is used to make the self-cure sealant system faster than the light cured system on a comparable number of teeth?
    experienced operator can apply the material to one or two quadrants of posterior teeth with one mix of material
  18. the light-cured material requires a ___________ application of light on each tooth to polymerize the sealant if a standard halogen light is used.
    20 seconds
  19. What is an advantage of using the light cured material?
    it doesn't require mixing, resulting in fewer bubbles and allows operator to place and cure the material when the operator is ready
  20. which color of sealant do pts usually prefer? But which is better for the clinician?
    • clear or tooth-colored
    • a color in contrast to tooth color is easier for clinician to identify
  21. Which type of sealants will wear faster than others?
    sealants that contain no organic filler particles
  22. Why do soe clinicians use flowable composites as sealants?
    because they are more heavily filled, and therefore are more resistant to wear while at the same time having adequate flow to enter the fissures
  23. What are the 8 steps in sealant placement?
    • Pumice: cleans and removes debris
    • rinse
    • isolation, VERY important
    • etch enamel: with 37% phosphoric acid, this provides retention of the sealant
    • rinse
    • dry (it should now have a frosty appearance) *may use a drying agent after this if you'd like*
    • apply material
    • polymerize
  24. very thin film of uncured resin on the cured sealant surface. surface will appear shiny and will be wet to the touch, because the set of the resin at its surface is inhibited by contact with oxygen in the air; it causes no harm but should be wiped off because it may taste bad
    oxygen- or air-inhibited layer
  25. any moisture on the tooth could result in ________ of the sealant
    FAILURE
  26. moisture to the sealant could come from what 3 areas?
    • saliva
    • leaky air-water syringe
    • moisture from pts breath
  27. failure in the sealant may be seen as what 3 things? Which is the worst?
    • immediate loss of slealant
    • complete or partial loss of sealant at subsequent visit
    • retained sealants that are leaking
    • leaking sealants are the worst, caries can form under the sealant
  28. What precautions can be taken to make sure that the etch material does not touch adjacent teeth or soft tissue? And so etch doesn't contact pt or clinicia?
    • use of matrix strips, or metal matrix bands
    • careful application of etch
    • wear protective eye wear always
  29. What material is used to identify the high spots in a sealant? What can be used to adjust high spots on a sealant? What types of sealants are more wear resistant and may take longer to adjust and cause a sore jaw or teeth?
    • articulating paper
    • bur or diamond
    • sealants with filler particles
  30. What are 7 chart entries that should be included about the sealant procedure?
    • date
    • pt, or parent consent
    • type of isolation
    • teeth and surfaces sealed
    • materials used
    • statement that pt or parent was informed of need for inspection and mtnc of sealant
    • adverse events
  31. What are 5 indications for the application of sealants?
    • permanent teeth with deep pits and fissures
    • primary molars with deep pits and fissures
    • evidence of caries susceptibility in primary dentition
    • steep cuspal inclines
    • deep, sticky fissures
  32. What are 2 contraindications for the application of sealants?
    • shallow cusps
    • highly coalesed pits and fissures
  33. When might teeth become sensitive?
    when the gingiva has receded and dentinal tubules are exposed to the oral cavity
  34. When are the dentinal tubules of teeth exposed?
    when the protective coating of the root by cementum gets worn away
  35. What are 3 other causes of tooth sensitivity that desensitizing agents would not be effective for treatment?
    • dental caries
    • cracked tooth
    • leaking restoration
  36. What are 3 common offenders of the odontoblasts that line the pulp and have extensions containing nerve endings that will cause sensitivity?
    • temperature: usually cold
    • sugars
    • acidic foods
  37. What are 4 common causes for the exposed dentin?
    • roots abraded by improper toothbrushing
    • loss of enamel and dentin from dietary acids
    • loss of tooth structure in the cervical part of the tooth by abfraction
    • scaling and root planing procedures
  38. What are 6 common causes of root sensitivity?
    • root caries- restoration needed
    • toothbrush abrasion- use desensitizing agent
    • erosion by acids- use desensitizing agent
    • abfraction associated with bruxism- use desensitizing agent
    • Scaling and root planing- use desensitizing agent
    • leaking restoration on the root- restoration needed
    • cracked tooth- restoration needed
  39. what are the two main methods or modalities for treatment of tooth sensitivity?
    • occluding (plugging) open tubules
    • desensitizing nerve endings
  40. What type of desensitizing agent passes through the dentinal tubules to the pulp and acts directly on the nerve, depolarized the nerve ending so it cannot fire and cause pain?
    potassium nitrate
  41. plugging the open ends of the dentin tubules will reduce fluid movement and stop pressure on the nerve endings, and this may be done by a _______ or _______ blocking process
    • chemical
    • mechanical
  42. true or false. One of the side effects of teeth bleaching is tooth and gum sensitivity, so some bleaching products contain potassium nitrate or fluoride to help reduce sensitivity
    true
  43. What is the hydrodynamic theory of dentinal sensitivity?
    • When cementum is worn away, dentinal tubules are exposed
    • odontoblasts line the pulp and have extensions in the dentinal tubules that contain nerve endings
    • when stimulus causes the fluid within the tubules to move, the sensitive nerve endings are deformed, causeing them to fire and produce a quick localized sharp pain
  44. Which type of desensitizing blocking process creates a bond with the dentin/tubules?
    mechanical
  45. Which type of desensitizing blocking process passes through the tubule and works directly on the nerve?
    chemical
  46. What are 3 chemicals used as chemical desensitizing agents?
    • potassium nitrate- (most common type. ex. sensodyne)
    • sodium citrate
    • strontium chloride
  47. true or false. No desensitizing agent provides permanent relief
    true
  48. List 6 different desensitizing agents that are available (table 7-4)
    • toothpaste (sensodyne)
    • fluoride gel/varnish
    • inorganic salt solutions
    • resin primers/ bonding agents
    • mineralizing agents
    • glass ionomer surface sealants
  49. What are 4 indications that may resulat in tooth sensitivity for use of desensitizing agents?
    • restorations
    • after scaling and root planing/prophy
    • gingival recession
    • bleaching
  50. What are 5 causes of tooth sensitivity that desensitizing agents might help with?
    • poor tooth brushing habits
    • hot and cold extremes
    • exposed dentinal tubules
    • acidic diet
    • bruxism
  51. What are 2 more permanent solutions for tooth sensitivity?
    • glass ionomer
    • composite restorations