An impression is made for the purpose of recording the anatomical landmarks and then to reproduce them on the cast to be poured.
The main 5 objectives of impression making are: PRESS
P – Preservation of remaining tooth structures
R – Retention
E – Esthetics
S – Stability
S – Support
Retention:
It is defined as “That quality inherent in the prosthesis which [...]
zero-degree teeth: posterior denture teeth having 0-degree cuspal angles in relation to the plane established by the horizontal occlusal surface of the tooth— called also zero-degree nonanatomic teeth—see NONANATOMIC TEETH
zinc oxide eugenol cement: a cement or luting agent resulting from mixing zinc oxide with eugenol (oil of cloves), typically dispensed in the form of a powder [...]
yield strength : the strength at which a small amount of permanent (plastic) strain occurs, usually 0.1% or 0.2%, and most frequently measured in MPa or psi
Young’s modulus: [Thomas Young (1773-1829) English physician and physicist] eponym for the constant of proportionality expressed in the stress-strain plot as the slope in the elastic region where elastic recovery [...]
1X-ray : the process of exposing objects to roentgen rays and projecting their shadow on sensitized surfaces
2X-ray : see ROENTGEN RAY
X-ray picture: see ROENTGENOGRAM
xenogenic graft : a graft from one species to another species— called also heterologous graft
xer·o·stomia : dryness of the mouth from lack of normal secretions
warp : torsional change of shape or outline; to turn or twist out of shape
wash impression slang: see FINAL IMPRESSION
wave length : the distance at any instant between two adjacent crests (or identical phases) of two series of waves that are advancing through a uniform medium. The wavelength varies inversely with the vibration rate or [...]