L5.Principles of Impressions Flashcards
When comparing a diagnostic (preliminary) cast to a master (final) cast, what anatomical features are u looking to capture in each?
Diagnostic: All anatomic landmarks
Master: Only the relevant anatomic landmarks covered by the prosthesis
During which denture visits are impressions taken?
1st (preliminary impression w/ stock tray) and 2nd (Final impression w/ custom tray)
What is the goal of a musostatic impression?
Musostatic impressions capture the state of the oral mucosa when external forces are not displacing it.
-Captures soft tissue in the undisplaced (resting) position
What is the goal of a Selective Pressure Impression?
Records selected tissue in a displaced (functional) position.
-Areas of the denture bearing tissue best able to tolerate load and provide support (i.e. Retromolar pads & buccal shelf) are impressed under increased pressure or functional load
What is the goal of a functional impression?
To capture tissues under pressure, in functional positions.
-Often accomplished using treatment denture and reline impression under normal function such as talking, chewing
What is captured in a Neutral Zone impression?
The potential space b/t the lips and the cheeks on one side and the tongue on the other.
-Records that area where the forces b/t the tongue and cheeks or lips are equal (=Neutral zone)
What is captured with an altered cast partial denture impression?
An altered cast partial denture impression captures part of the functional (denture bearing) tissue with a custom tray attached to the prosthesis framework or a similar structure.
