What are Primary impressions?
The initial and less detailed mould of a patients teeth and gums
What are Primary impressions taken with?
Stock trays and Alginate
List the purpose of Primary impressions
1) For a working replica of a patients oral structures
2) For treatment plan and design
3) Allows us to fabricate a custom tray
What is a Custom tray?
An individualised impression tray made from the cast fabricated from the primary impression
What are Secondary impressions?
A precise and detailed recording of the oral tissues used to fabricate a custom-fit prosthesis
List the 8 requirements for a Custom tray
1) Smooth edges
2) Uniform thickness
3) Rigid thickness
4) Dimensional Stability
5) Easily adjustable
6) Proper handle placement
7) Correct extension on primary cast
8) Tissue stops present
Describe ‘Smooth edges’
Tray borders should be free of sharp or rough edges
Describe ‘Uniform thickness’
Consistent thickness around the entire tray perimeter
Describe ‘Rigid material’
Constructed from firm and non-flexible material
Describe ‘Dimensional stability’
Maintains shape without warping or distorting
Describe ‘Easily adjustable’
Allows for minor modifications chairside
Describe ‘Proper handle placement’
Positioned to avoid lip distortion and ensure comfort
Describe ‘Correct extension on primary cast’
Accurately extends to the required anatomical landmarks
Describe ‘Tissue stops present’
Adequate stops to ensure proper spacing and fit
