lec 9 - Impression Procedures and Materials for Removable Partial Dentures Flashcards
- Negative likeness or an imprint made placing some soft, semifluid material in the mouth and allowing that material to set.
IMPRESSION
usually used for cast restoration and are elastic when removed from the mouth.
Impression material
IDEAL IMPRESSION MATERIAL (7)
- Complete plasticity before cure (set)
- Sufficient fluidity to record define detail
- The ability to wet the oral tissues
- Dimensional accuracy
- Dimensional stability
- Complete elasticity after cure
- Optional utilities
IMPRESSION MATERIAL CLASSIFICATION
(1) Rigid Impression Materials
(2) Thermoplastic Impression Materials
(3) Elastic Impression Materials
- Set to rigid consistency
- Cannot be removed from the mouth without fracture and reassembly.
RIGID IMPRESSION MATERIALS
RIGID IMPRESSION MATERIALS (2)
Plaster of Paris
Metallic Oxide Paste
- One type of impression material is which has been used in dentistry for over 200 years.
plaster of Paris
was once the only material available for removable partial denture impressions, but now elastic materials have completely replaced the impression plasters in this phase of prosthetic dentistry.
plaster of Paris
usually some form of a zinc oxide–eugenol combination.
METALLIC OXIDE PASTE
they are not used as primary impression materials and should never be used for impressions that include remaining natural teeth.
METALLIC OXIDE PASTE
THERMOPLASTIC MATERIALS (2)
Modelling plastic
Impression waxes and natural resins
- Modelling Compound
Modelling plastic
- Oldest impression material used in prosthetic dentistry
MODELLING PLASTIC
- Most often used for border correction (border molding) of custom impression trays for distal free end classifications. It is manufactured in several different colors, each color being an indication of the temperature range at which the material is plastic and workable.
MODELLING PLASTIC
most commonly used modeling plastic for corrected impressions for extension base areas. (softens around 132°F/55.55°C)
- Red-brown
obtainable in stick form used in border molding
Red, Gray, and Green
- Used to record non-undercut edentulous portions of the oral cavity and are generally used in combination with other impression materials like polysulfide, ZOE impression paste or impression compound.
IMPRESSION WAXES AND NATURAL RESINS
- May be used to correct the borders of impressions made of more rigid materials thereby establishing optimum contact at the border of the denture.
IMPRESSION WAXES AND NATURAL RESINS