Today's dental materials

Question 1

what do we do after alginate

Answer 1

1) alginate impression
2) gypsum (microstone) to create positive replica

Question 2

CAD CAM

Answer 2

1) models can be milled or printed
2) same with crowns

Question 3

type I gold

Answer 3

1) soft, low stress
2) inlays

Question 4

type II

Answer 4

1) medium, moderate stress
2) inlays and onlays

Question 5

type III

Answer 5

1) hard, high stress
2) crowns, thick veneer crowns, short span fixed prosthesis

Question 6

type IV

Answer 6

1) extra hard, high stress
2) thin veneer crowns, long-span fixed prosthesis, removable prosthesis

Question 7

historical restorations

Answer 7

1) lost wax, investment, centrifugal casting
- investment
- wax pattern sprued
- base affixed to ring
- pouring investment into mold
- centrifugal casting machine
- melting gold
- cut sprue off
- polish
2) now it is milled and printed

Question 8

digital dentists

Answer 8

1) seeing restorations with CAD/CAM with or without chairside digital scanner
2) adaptive impression scanning by 3Shape

Question 9

leucite reinforced and LDS are

Answer 9

1) pressed
- ingots
2) milled
- blocks

Question 10

zirconia

Answer 10

1) porcelain fused zirconia
- ingots
- bilithic
2) milled blocks
- monolithic

Question 11

leucite reinforced glass ceramic

Answer 11

1) potassium and aluminum tectosilicate
- particle filled glass
2) esthetic with functional strength
- for anterior dentition and partial coverage for posterior teeth
- prior to LDS
3) empress I and II
4) pressed or milled
5) 1990

Question 12

lithium disilicate

Answer 12

1) quartz
2) lithium dioxide, phosphate oxide, alumina, and potassium oxide
3) interlocking nature of crystal structure
- esthetic and strong
4) ingots (pressed) or monolithic (CAD/CAM)
5) eMAX

Question 13

ivolar versatile materials

Answer 13

1) medium translucency and shade gradation
- full contour crowns, full contour 3 unit bridges
2) medium translucency
- same as above
3) low translucency
- above +full contour 4 unit bridges with 2 pontics + crown frameworks + 3 unit bridge framework with 2 pontics
4) medium opacity
- crown frameworks + 3 unit bridge framework with 2 pontics

Question 14

what’s an ingot

Answer 14

1) LDS, porcelain, or metal
2) uniform size and shape that can be used for casting, pressing, or becoming part of a restoration
3) ingot is liquefied via high temperature and pressed through a casting ring

Question 15

ingots are used in

Answer 15

1) pressed LDS
-variety of translucencies and opacities to accommodate the patient’s esthetics and clinicians demand for strength
2) layering of porcelain on zirconia (bilithic restorations)

Question 16

what does pressed mean

Answer 16

1) heating an ingot at high temperature then heat pressing under a vacuum, fabricating a restoration through an investment
2) mostly done at dental labs

Question 17

pressed components

Answer 17

1) heat plunger
2) ingot
3) sprue mold
4) burned out wax / pattern of restoration (wax up can be CAD/CAM)
5) investment

Question 18

LDS in block form

Answer 18

1) intermediate form 130-160 MPa
2) after the restoration is milled, it is placed in a ceramic furnace to be crystalized, strength increased to 500 MPa (bonded)
3) metal lug assures positive lock in the mill

Question 19

crystallization of LDS

Answer 19

1) the LDS grows, interlocks, and concentrates
2) inreasing its flexural strength during this process
3) pre-crystallized
- 40% isolated lithium metasilicate
- crystals in a glass matrix
4) IPS Emax CAD after firing
- 70% lithium disilicate
- crystals in a glass matrix

Question 20

zirconia

Answer 20

1) zirconia dioxide
2) two types:
- tetragonal and cubic
3) tetragonal is used for toughening
4) cubic is used to increase translucency
5) balance the two for strength and aesthetics
6) needs to be sintered at 1500-1600C to enact state change
- heat shrinkage 20-25%
- stronger and more translucent

Question 21

leucite reinforced strength

Answer 21

1) 160-185 MPa
- glaze up to 240 MPa

Question 22

lithium disilicate strength

Answer 22

1) 400-500 MPa
- high value assumes bonded

Question 23

zirconia strength

Answer 23

1) bilithic
- 1000 MPa
2) Milled
- 500-1000 MPa

Question 24

where to use leucite reinforced

Answer 24

1) veneers
2) inlays/onlays
3) must bond

Question 25

where to use LDS

Answer 25

1) veneers (0.4)
2) inlays/onlays
3) crowns 1.0 mm bonded
4) bridges (to second premolar)
5) 12 mm connector

Question 26

zirconia uses

Answer 26

1) inlays/onlays
2) crowns 1 mm
3) no bond
4) bridges 12 mm
5) anterior crowns (bilithic)

Question 27

how is strength measured

Answer 27

1) flexural strength
- applying a load to a material specimen that is supported at each end, which combines the forces found in compression and tension
2) MPa: a unit for measure that represents how much stress a material can withstand without failing

Question 28

esthetics and functional medicine

Answer 28

1) knowledge of the material is key
2) adhesives play an integral role in success
- bonded Emax is much stronger than unbonded
- short zirconia or Emax in posterior require bonding for retention

Question 29

esthetics ranking

Answer 29

1) leucite (best)
2) LDS and bilithic zirconia
3) monolithic zirconia (worst)