6. Record bases and occlusion rims

Question 1

Define record base

Answer 1

-interim denture base used to support the occlusion rim materials

Question 2

Whats another name for a record base?

Answer 2

base plate

Question 3

What type of impression is used for record base in favorable cases?

Answer 3

mucostatic impressions

Question 4

What type of impression is used for record base in unfavorable cases?

Answer 4

functional impressions w/custom tray

Question 5

Record bases are used in these stages… (4)

Answer 5

1. cast mounting
2. arragement of denture teeth
3. trial placement (wax try in)
4. Flasking

Question 6

Record base purpose when carrying an occlusal rim? (4)

Answer 6

◦ Centric relation.
◦ Vertical dimension.
◦ Location of denture teeth.
◦ Occlusal plane.

Question 7

Recordbase thickness?

Answer 7

2mm

Question 8

Record base dimensional stability?

Answer 8

Acrylic resin shrinks over time, so they must be

made 24h before being used

Question 9

Record base materials? (4)

Answer 9

• self curing resin
• light curing resin
• truwax (fragile, goodfit)
• heat curing resin (volume changes w/curing)

Question 10

Record base manufacturing border design: Anatomical impressions, what class? up to where? (2)

Answer 10

• class I & II

- mucogingival junction of cast

Question 11

Record base manufacturing border design: functional impressions, what class? up to where? (2)

Answer 11

• class III & IV

- up to bottom of vestibule of cast

Question 12

Record base manufacturing border design: Anatomical impressions, where is the survey line? Where do we draw? (3)

Answer 12

• greatest prominence of contour in relation to the planned path of placement of a restoration
  ◦ Draw line 1-2 mm passed survey line.
  ◦ If there is no survey line: draw line 2-3 mm shorter than bottom of the vestibule.

Question 13

Record base manufacturing border design: upper base design? (3)

Answer 13

◦ Draw line 1-2 mm passed survey line.
◦ Safety distance from frenuli.
◦ Posteriorly: Up to hamular notches and palatine foveae.

Question 14

Record base manufacturing border design: lower base design?

Answer 14

◦ Draw line 1-2 mm passed survey line.
◦ As usually there is no survey line: draw line
2-3 mm shorter than bottom of the vestibule.
◦ Safety distance from frenuli, retromolar trigone and retromylohyoid space.

Question 15

How do we adapt the record base to the cast when making it?

Answer 15

sponge

Question 16

Making a record base is similar to..?

Answer 16

making a custom tray

Question 17

Where do we trim the record base up to?

Answer 17

up to the free functional area of mucosa

Question 18

What do we do with the patient for the clinical assessment of the record base? (5)

Answer 18

◦ Pull lips.
◦ Thrust tongue.
◦ Open mouth.
◦ Move mandible laterally. ◦ Say letter “A”, “K”, “G” (ensures proper baseplate extension)

Question 19

Define occlusal rim:

Answer 19

Occluding surfaces fabricated on interim/final denture bases for MAXILLOMANIDUBLAR relation records & arranging teeth

Question 20

An occlusal rim determines what esthetic information? (6)?

Answer 20

• Location of upper incisal edges.
• Location of upper lip while smiling and at rest.
• Occlusal plane.
• Dental midline.
• Location of the canines.
• Tooth size.

Question 21

An occlusal rim determines what functional information? (4)

Answer 21

• Vertical dimension.
• Centric relation
• Cast mounting:
◦ Help in facebow transfer.
◦ Help in intermaxillary relation record.

Question 22

Occlusal rim material can NEVER be…?

Answer 22

SOFT waxes

Question 23

Material for occlusal rims? (2)

Answer 23

• Hard waxes: Moyco type.

* Godiva: Rigid & Hard to handle.

Question 24

Height of upper occlusal rims?

Answer 24

• 12 mm anteriorly

- 8 mm posteriorly

Question 25

Thickness of upper occlusal rims?

Answer 25

• 5mm anteriorly

- 8mm posteriorly

Question 26

Inclination of upper occlusal rim?

Answer 26

• anteriorly 15-20 degrees

- posteriorly 45 degrees

Question 27

Lower occlusal rim height and thickness?

Answer 27

8mm

Question 28

Finishing touches of occlusal rim: what materials do we use for hard wax? (2)

Answer 28

◦ Hot wax knife.

◦ Venetian plaster spatula

Question 29

Finishing touches of occlusal rim: what materials do we use for Godiva? (2)

Answer 29

◦ Blades (cutter).

◦ X-acto blade.