Digital Technologies Part 2

Question 1

most chairside milling machines are:

Answer 1

4 axis mill

Question 2

most laboratory milling machines are:

Answer 2

5 axis mill

Question 3

describe the 4 axis mill

Answer 3

• burs move in 3 axes X,Y and Z
• material/block rotates in 1 additional axis (3+1 milling machine)
• the addition of the 4th axis (A axis) allows the block to automatically rotate 180 degrees so that it can mill intricate details

Question 4

describe the 5 axis mill

Answer 4

• the milling block is rotated in additional axes
• can mill complex designs such as implant superstructures, RPD frameworks, complete dentures
• the milling block is rotated in additional axes
• can mill more complex designs such as implant superstructures, RPD frameworks, dentures

Question 5

what is the difference in speed between the 4 axis mill and the 5 axis mill

Answer 5

• 4 axis mill faster in single restorations
• 5 axis mill faster in multiple restorations

Question 6

what is the difference in block size between the 4 axis mill and the 5 axis mill

Answer 6

• 4 axis mill: max 80 x 16mm
• 5 axis mill: 98.5 x 30 mm

Question 7

what is the difference in undercuts between the 4 axis mill and the 5 axis mill

Answer 7

4 axis mill: disabled
- 5 axis mill: limited

Question 8

what is the difference in indications between the 4 axis mill and the 5 axis mill

Answer 8

• 4 axis mill: crown and short FPD
• 5 axis mill: long FPD and dentures

Question 9

accuracy and resolution is _____ related to the number of axes

Answer 9

not

Question 10

what materials are used in a wet mill

Answer 10

-lidisilicate
- feldspathic porcelain
- Co-Cr metal

Question 11

what materials are used in dry mill

Answer 11

• resins
• Zr

Question 12

what materials are used in dry and wet mills

Answer 12

• Zr
• some metals such as titanium
• resins

Question 13

the liquid in a wet mill is:

Answer 13

a combination of distilled H2O and another liquid (manufacturer specific)

Question 14

describe the maintenance on dry and wet milling

Answer 14

• still required with a dry mill
• dry and wet mills can vary in the level of maintenance required and level of noise during operations

Question 14

describe the functional movement of the bur

Answer 14

• bur movement is related to the tooth preparation
• successful tooth preparation is required for successfully milling
• bur dimensions influence the milling outcome

Question 15

the margin of the restoration should be at least ____ of the width of the bur tip

Answer 15

1/2

Question 16

cusp/fossa has to be at least as wide as:

Answer 16

the diameter of the bur

Question 17

tooth preparation cannot exceed the height of:

Answer 17

the bur

Question 18

margin thickness depends on:

Answer 18

bur size and crown material

Question 19

what is the pre acquisition checklist

Answer 19

• administration tab complete
• correct material selected
  -patient evaluation
• scanning armamentarium
  -optragate or isovac placed
  -proper isolation

Question 20

what is done in patient evaluation for cadcam

Answer 20

• maximum opening
• tongue size
• cheek elasticity
• buccal fat pad
• third molars

Question 21

what is the scanning armamentarium

Answer 21

• isovac or optragate
• 4x4 guaze
• cotton rolls
• mirror
• forceps

Question 22

what is the depth of field for scanners

Answer 22

0-16mm

Question 23

what are the golden rules of scanning

Answer 23

• always start on an area that the scanner knows and then slowly blending in the new area
• if it ever freezes or loses its place stop and remove the scanner and reposition to a known location

Question 24

what are the prepped quadrant scanning steps

Answer 24

- occlusal - buccal - lingual - distal interproximal - mesial interproximal - corrective scans

Question 25

what is done in the scan evaluation

Answer 25

- examining for missing areas in the scan - we need to capture the complete prep and adjacent interproximals - fix each missing area individually with a short scan - repeat for each missing area - be careful not to make the scan file too large

Question 26

what is the opposing quadrant scanning steps

Answer 26

- occlusal - buccal - lingual - corrective scans

Question 27

if you cannot get it to begin a scan or recognize teeth you can use ____ to help the scanner pick it up

Answer 27

optispray

Question 28

what are the design steps

Answer 28

- define margin - design morphology - ensure the restoration fits the arch

Question 29

how do you define the margin

Answer 29

use the double click to enter editing mode and then draw in the areas you want to replace then double left click to reconnect it to the margin

Question 30

how do you change the moprhology

Answer 30

add, smooth, subtract

Question 31

what color do you want for contacts

Answer 31

- we want to have light blue for the interproximal contacts and occlusal

Question 32

for zirconia what should the contacts be

Answer 32

add a little green at the occlusal portion of the interproximal contact

Question 33

what are the milling steps

Answer 33

- milling the crown here in 250 - firing or sintering - glazing

Question 34

what are the milling steps

Answer 34

- fill our the cerec block form and get the block from mary jane - enter the barcode here and hit start

Question 35

what are the cerec MC XL zirconia burs

Answer 35

- finisher 10 - shaper 25 RZ

Question 36

what are the cerec MC XL lithium disilicat eburs

Answer 36

- step bur 20 - cylinder pointe bur 20S

Question 37

what are the steps after milling for zirconia

Answer 37

- find which of the speedfire units the job got sent to, select it, then "pre drying and sintering" - place the crown intaglio side up and start it (add 15 mintues to cool) dont touch when the temperature on the screen is over 250 - take the crown to chris to glaze

Question 38

what are the steps after milling for emax

Answer 38

- take the crown up to chris to fire and glaze - do not use the speedfires here in 250