PROBLEM
|
REASON
|
SOLUTION
|
Material
Sets too Fast
|
Warm Temperatures
Material Expired
Improper Ratio of Base
Catalyst Mixture.
|
Cool Materials to 70-72
F.
Check expiration date of material. NOTE: Always make sure that
office staff rotate stock so that the oldest material is used
first. This should be observed for all materials with or without
expiry dates.
Always make sure that
equal amounts 1:1 ratio (Varies from manufacturer) of Base and
Catalyst are used. Extrude 1/4 inch of material out of cartridge
for even flow of material
|
Material
Sets too Slow
|
Material
too Cold |
Warm material
to 70 - 72 F Poly Vinyls are very sensitive to fluctuations in temperature. |
Material
Does not Set
|
Sulfer contamination
or Amines Layer Contamination
Excessive Hemostatic
Agent Residual (ie. Ferric Sulfates, Aluminum Chlorides) Eugenol
Based Cements, or filling materials.
|
Sulfer found in most
gloves can inhibit the set of materials (Both Putty and Fluid
materials) Acrylic Monomers, Hemostatic Agents, Composite Restorations,
Eugenol will also inhibit the Set Time.
Rinse Patient and Site
well with a High Alcolhol Based Mouth Rinse And Dry Thoroughly
before taking impression.
|
Porosity
in Impression around Preparation Site
|
Sulfer based Astringents/Hemostatic
agents reacting with Material
Excessive Bleeding
or Moisture in area of Preparation
|
Before Final
Impression is Taken, Rinse area well with water, and Dry Thoroughly.
|
Porosity
or Bubbles in Stone Cast
|
Hydrogen
Outgassing of Material after final polymerization (Polyvinyls Only)
Pouring Impression Too Soon! |
Ideally one should
wait several hours before pouring Polyvinyl Impressions to Allow
for total emission of Hydrogen.
NOTE: If you
must pour Impression Immediately After Procedure and Porosity
has been a problem. Try rinsing the Impression with warm soapy
water for 10 minutes to speed up outgassing reaction. Also soap
acts as a debubblelizer for stone to be poured. Be sure to rinse
soap thouroughly out of impression before pouring otherwise soap
will create bubbles in stone cast.
|
Material
"Sticks" to Stone Cast
|
Contamination
of Impression Material at Time of Impression Taking (Sulfur etc.)
|
Make sure
no contamination has occurred during procedure. Thoroughly Rinse
Patient and Site. Refer to problem and solution #3. |
Drag
or Distortion of Impression Material
|
Excessive Moisture
Wash material Too Viscous
for Procedure.
Tray Not Fitting Arch
Properly or Too Flexible for Specific Technique.
Impression Tray moved
before material was set.
Tray not seated properly
|
Dry Patient Thoroughly
Use a wash Material
with a Lower viscosity
Select a Large enough
Tray. Should have approx 3mm width or clearance from Buccal, Mesial,
Lingual, Distal, aspects. Make sure tray is Rigid enough.
Hold tray passively
without movement.
Preseat tray in mouth
before taking impression!
|