6. Record bases and occlusion rims Flashcards
Define record base
-interim denture base used to support the occlusion rim materials
Whats another name for a record base?
base plate
What type of impression is used for record base in favorable cases?
mucostatic impressions
What type of impression is used for record base in unfavorable cases?
functional impressions w/custom tray
Record bases are used in these stages… (4)
- cast mounting
- arragement of denture teeth
- trial placement (wax try in)
- Flasking
Record base purpose when carrying an occlusal rim? (4)
◦ Centric relation.
◦ Vertical dimension.
◦ Location of denture teeth.
◦ Occlusal plane.
Recordbase thickness?
2mm
Record base dimensional stability?
Acrylic resin shrinks over time, so they must be
made 24h before being used
Record base materials? (4)
- self curing resin
- light curing resin
- truwax (fragile, goodfit)
- heat curing resin (volume changes w/curing)
Record base manufacturing border design: Anatomical impressions, what class? up to where? (2)
- class I & II
- mucogingival junction of cast
Record base manufacturing border design: functional impressions, what class? up to where? (2)
- class III & IV
- up to bottom of vestibule of cast
Record base manufacturing border design: Anatomical impressions, where is the survey line? Where do we draw? (3)
- 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.
Record base manufacturing border design: upper base design? (3)
◦ Draw line 1-2 mm passed survey line.
◦ Safety distance from frenuli.
◦ Posteriorly: Up to hamular notches and palatine foveae.
Record base manufacturing border design: lower base design?
◦ 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.
How do we adapt the record base to the cast when making it?
sponge
Making a record base is similar to..?
making a custom tray
Where do we trim the record base up to?
up to the free functional area of mucosa
What do we do with the patient for the clinical assessment of the record base? (5)
◦ Pull lips.
◦ Thrust tongue.
◦ Open mouth.
◦ Move mandible laterally. ◦ Say letter “A”, “K”, “G” (ensures proper baseplate extension)
Define occlusal rim:
Occluding surfaces fabricated on interim/final denture bases for MAXILLOMANIDUBLAR relation records & arranging teeth
An occlusal rim determines what esthetic information? (6)?
- Location of upper incisal edges.
- Location of upper lip while smiling and at rest.
- Occlusal plane.
- Dental midline.
- Location of the canines.
- Tooth size.
An occlusal rim determines what functional information? (4)
• Vertical dimension. • Centric relation • Cast mounting: ◦ Help in facebow transfer. ◦ Help in intermaxillary relation record.
Occlusal rim material can NEVER be…?
SOFT waxes
Material for occlusal rims? (2)
- Hard waxes: Moyco type.
* Godiva: Rigid & Hard to handle.
Height of upper occlusal rims?
- 12 mm anteriorly
- 8 mm posteriorly
Thickness of upper occlusal rims?
- 5mm anteriorly
- 8mm posteriorly
Inclination of upper occlusal rim?
- anteriorly 15-20 degrees
- posteriorly 45 degrees
Lower occlusal rim height and thickness?
8mm
Finishing touches of occlusal rim: what materials do we use for hard wax? (2)
◦ Hot wax knife.
◦ Venetian plaster spatula
Finishing touches of occlusal rim: what materials do we use for Godiva? (2)
◦ Blades (cutter).
◦ X-acto blade.
