3 impression techniques and temporization.ppt

3 impression techniques and temporization

1. Dr Huma Farid

4. GINGIVAL RETRACTION
1.Proper horizontal displacement of the tissues at the coronal
margins.
2.Vertical displacement of marginal tissues to expose undercuts
apical to the finish line.
3.Gingival bleeding must be arrested.
4.Complete dry field.
◦Not needed for supragingival margins

5. Methods of retraction
◦Electrosurgery
◦Placement of retraction cord (Mechanical)
◦Retraction cords can be soaked in hemostatic or astringent
solution (chemo mechanical)
Epinephrine
Aluminium chloride
Ferrous sulphate
◦Blasts of air from triple syringe over impression
material to flow material into crevices

7. Braided cords are preferred than twisted
retraction cords
Available in various thickness
Should be placed for 2-3mins for sufficient
retraction
Double cord technique

10. Impression
material
viscositiesadvantages disadvantages
Silicone based
(additon )
Putty
Heavy body
Regular
Light body
Wash
accuracy,
dimensional stability
Non toxic ,non
allergic
Cost
Hydrophobic
material
poly ether Regular accuracy
Non toxic ,non
allergic
Cost
hydrophobic
polysulphide Light
Heavy body
Longer working time
accuracy
Offensive smell
Longer setting
time
Difficult
handling
Reverrsible
hydrocollide
------------Hydrophobic
Fine detail recording
Difficult
handling
Poor
Dimensional
stability

11. Single stage technique
Two stage techniques
◦Unspaced technique
◦Spaced technique
Recording putty impression before preparation and light
body impression after preparation
Use of polythene spacer while recording putty
impression and final impression with light body
Gouging away putty impression around prepared tooth
impression and relining impression with light body
impression material.

13. Polymer material
Wax interocclusal record
Zn Oxide eugenol paste record

14. •Difference between provisional crown and
temporary crown
•Temporization is important for
–Protection of prepared dentin
–Maintain appearance
–Prevent tilting,overeruption by maintaining contact
points and occlusion
–Maintain ginigival and pulpal health
–Maintain function

15. Custom made
◦Acrylic ( self cured)
Preformed temporary crown
◦Polycarbonate
◦Steel
◦Aluminium

18. 1.Checking of fit of crown and margin on die
2.Check for seating of crown
3.Check for margin defects ( Negative ledges,
positive ledges or overhang margins).
4.Check for fit of inner surface of crown by
disclosing agents (colloidal graphite spray)
5.Check for tightness of contact with floss

19. 1.Check for retention of crown ( not too tight ,
no pivoting)
2.Check for buccal and lingual contours
3.Check for shade matching
4.Check and adjust occlusion

24. Crown should be cemented quickly
Firm pressure by dentist or patient by biting on
a cotton roll
Maintain isolation till the cement is set
Excess cement is removed by probes on the
buccal and lingual surface. Interproximal
surfaces are cleaned using dental floss while
assistant applies digital pressure on the crown.