Casting alloys and implants (Ch 11 and 12)

Question 1

what is an alloy

Answer 1

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

Question 2

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

Answer 2

1. high noble
2. noble
3. base metals

Question 3

what is the purpose of a gold alloy

Answer 3

• 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

Question 4

what is palladium

Answer 4

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

Question 5

what is platinum

Answer 5

• gold alloy
• expensive
• high melting point
• difficulty mixing with gold

Question 6

what is high noble

Answer 6

• 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

Question 7

what is noble

Answer 7

• 25% noble elements, no requirement for gold

- 75% consists of base metals

Question 8

what are base metals

Answer 8

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

Question 9

what is the biocompatibility of noble metals

Answer 9

• more biocompatible because they corrode less than base metals

Question 10

what can cause allergic reactions in base metals

Answer 10

• 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

Question 11

what are wrought metal alloys

Answer 11

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

Question 12

what are wires

Answer 12

• 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

Question 13

what are arch wires made of

Answer 13

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

Question 14

what do wires do

Answer 14

• 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

Question 15

what is the gauge of the wire

Answer 15

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

Question 16

what are brackets and bands

Answer 16

• 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)

Question 17

what are lingual retainers

Answer 17

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

Question 18

what are implant materials used to replace

Answer 18

• one or more single units

- support a full denture

Question 19

what are the 3 main types of implant materials

Answer 19

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)

Question 20

what are the 2 different types of implants

Answer 20

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

Question 21

what materials are used in implants and why

Answer 21

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

Question 22

how does osseointegration happen

Answer 22

• 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

Question 23

what are some contraindications for implants

Answer 23

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

Question 24

what are some indications for using implants

Answer 24

• 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

Question 25

what is home care like for implants

Answer 25

• 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

Question 26

what antibacterial agents should be used with implants

Answer 26

• 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

Question 27

scaling for patients with implants

Answer 27

• 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

Question 28

questions to ask patients with implants

Answer 28

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

Question 29

what should we be looking for visually in patients with implants

Answer 29

• swelling
• erythema
• bleeding
• other indications of developing problems

Question 30

what kind of probe should be used on perio patients

Answer 30

• plastic probe with light touch

Question 31

things not recommended for patients with implants

Answer 31

• polishing
• conventional steel curettes
• US scalers
• air polishers

Question 32

what is implant failure and what might cause it

Answer 32

• 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