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Dental Materials > Casting alloys and implants (Ch 11 and 12) > Flashcards

Casting alloys and implants (Ch 11 and 12) Flashcards

1
Q

what is an alloy

A
  • combination of metals
  • made using the ‘lost wax technique’
  • gold alloys = not pure gold
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2
Q

what does the ADA classify dental casting alloys based on (3 categories)

A
  1. high noble
  2. noble
  3. base metals
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3
Q

what is the purpose of a gold alloy

A
  • by combining gold with other metals to form an alloy, it creates the characteristics and hardness required as an excellent choice for an indirect restoration
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4
Q

what is palladium

A
  • gold alloy
  • good corrosive resistance
  • increases hardness of the alloy
  • was less expensive but currently is more expensive than gold
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5
Q

what is platinum

A
  • gold alloy
  • expensive
  • high melting point
  • difficulty mixing with gold
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6
Q

what is high noble

A
  • 60% noble elements
  • 40% must be gold
  • 20% palladium and platinum
  • base metals make up the remaining 40%
  • does not tarnish or corrode
  • usage declining because of high cost of gold
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7
Q

what is noble

A
  • 25% noble elements, no requirement for gold

- 75% consists of base metals

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8
Q

what are base metals

A
  • less than 25% noble elements
  • primary base metals used for cast alloys
  • copper
  • silver
  • nickel
  • zinc
  • tin
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9
Q

what is the biocompatibility of noble metals

A
  • more biocompatible because they corrode less than base metals
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10
Q

what can cause allergic reactions in base metals

A
  • contain nickel and beryllium
  • nickel has an incidence of 9-12% allergy in population
  • greater incidence in women, thought to be due to nickel in jewelry
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11
Q

what are wrought metal alloys

A
  • an alloy that has been mechanically changed into another form to improve its properties
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12
Q

what are wires

A
  • wrought metal alloys
  • clasps on prosthetic appliances
  • lingual arch wires
  • ligature wires for ortho and oral surgery for jaw fractures
  • preformed provisional crowns: mostly for pedo to maintain tooth till it exfoliates, not used widely in adults
  • endodontic files: twisted wire to produce cutting edges to clean and shape canals
  • composed of base metals
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13
Q

what are arch wires made of

A
  • stainless steel
  • cobalt-chrome-nickel
  • titanium
  • or an alloy of nickel and titanium called nitinol
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14
Q

what do wires do

A
  • resist deformity
  • resistance creates ‘memory’
  • wire tries to return to its original shape
  • is it the ‘memory’ that exerts the forces that move the teeth
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15
Q

what is the gauge of the wire

A
  • diameter of the wire
  • gauge is numbered by thickness
  • thicker the wire = smaller the number
  • thinner wire has more memory
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16
Q

what are brackets and bands

A
  • cemented onto the teeth
  • formed from stainless steel alloys/plastics
  • retain the arch wires (arch wires are held to the brackets by ligature wire or elastics)
17
Q

what are lingual retainers

A
  1. placed after orthodontic tx
  2. long-term stabilization
  3. ensures patient cooperation
  4. obstacle to flossing
  5. wire adapter to the lingual surfaces
    a) a thick wire bonded on the cuspids or
    b) thin wire bonded on each tooth
18
Q

what are implant materials used to replace

A
  • one or more single units

- support a full denture

19
Q

what are the 3 main types of implant materials

A
  1. subperiosteal
  2. transosteal: a) severe resorption, b) lacks support
  3. endosteal (endosseous): most widely used; single tooth replacement for supporting CUD, partial, fixed bridges; good success rate (see pics in ppt)
20
Q

what are the 2 different types of implants

A
  1. one stage: good bone quality; sufficient bone; good initial stability; crown places
  2. two stage: safer/more conservative; lacks bone support; denture cases
    stage 1: implant
    stage 2: healing abutment
21
Q

what materials are used in implants and why

A
  1. titanium
  2. titanium alloys
    - why?: osseointegration: the process whereby bone grows around a titanium implant
22
Q

how does osseointegration happen

A
  • surface layer of oxides integrate with bone
  • some implant metals have: a surface coating of a thin layer of calcium phosphate (in the form or hydroxyapatite) or plasma proteins
23
Q

what are some contraindications for implants

A

patients who:

  • have medical condition (advanced cardio/respiratory disease)
  • conditions that affect ability to fight disease (diabetes)
  • bisphosphonates - osteoporosis
  • compromised immune system
  • smokers
  • patients unable to conduct good OH
24
Q

what are some indications for using implants

A
  • able to restore dentition
  • preserving tooth structure
  • gingiva is healthier
  • preserves bone because not resorbing if placed soon after exo
  • complete dentures - better function
  • esthetics
25
Q

what is home care like for implants

A
  • customized
  • use disclosing agents: check daily for first few weeks, check periodically after patient becomes proficient at cleaning, give disposable mouth mirror
  • brushes: use ultra soft bristles, interproximal burgess with nylon coating, end tuft brushes (heating the plastic handle), electric brushes, non-abrasive tp
  • floss: thicker floss, superfluous, yarn, gauze strips, wooden plaque removers
26
Q

what antibacterial agents should be used with implants

A
  • chx: 1-2 weeks after second surgical stage; swish gently for 30 seconds, 2x/day; apply directly with inter proximal brush; stains
  • essential oil rinse
  • biological seal with epithelium
27
Q

scaling for patients with implants

A
  • 3 month recare for one year
  • 4 month recare for second year
  • 6 month recare after
  • use plastic instruments
  • graphite curettes
  • metal instruments with teflon or gold coating
  • special ultrasonic scalers for implants
28
Q

questions to ask patients with implants

A
  • implant mobility
  • soreness
  • bleeding of periodontal-implant tissues
  • looseness of the prosthesis
  • pain with chewing
29
Q

what should we be looking for visually in patients with implants

A
  • swelling
  • erythema
  • bleeding
  • other indications of developing problems
30
Q

what kind of probe should be used on perio patients

A
  • plastic probe with light touch
31
Q

things not recommended for patients with implants

A
  • polishing
  • conventional steel curettes
  • US scalers
  • air polishers
32
Q

what is implant failure and what might cause it

A
  • lack of bony integration with the implant
  • due to:
    1. poor surgical technique, excessive heat when drilling
    2. infection of the implant site
    3. poor quality of bone
    4. placing loading forces on the implant too soon

Dental Materials (18 decks)

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