PVS/VPS Flashcards
why traditional
1) digital penetrate the market slowly
2) the gauging accuracy immediately
PVS advantages
1) easy of delivery
2) accuracy and detail
2) setting time controls
4) viscosity controls
5) self life/stable
6) reasonable tear strength
PVS disadvantages
1) technique sensitive
2) timing, mix and delivery critical
3) hydrophobic nature
4) undercuts - removal and rebound accuracy
look at a case
1) usually put smaller cord 00
2) then second cord #1
- but size can vary
the single most critical factor
1) tissue management
- hemostasis and retraction
2) note these are independent and intentional processes
3) viscostat - ferric sulfate
- aggressively scrub into the cavity to compress blood clots
4) warning: cords give you inappropriate hemostasis
- use knitted cord
- paint viscostat into tissue one more time before packing into wet sulcus
most common errors
1) packing started prior to hemostasis
2) wrong diameter
3) using one cord when 2nd or 3rd needed
4) cord impregnated with hemostatic solution priot to placement
5) area kept too dry too early
- irritation to tissue
diode laser
1) cauterize tissue
three strategies
1) mechanical retraction and hemostasis
2) laser troughing
3) hydraulic impresion (DO NOT DO)
timing of material
1) working time
2) number of units and complexity
3) intraoral set time, relationship to accuracy vs potential for distortion
hydrophilicity
1) high hydrophilicity to the final pour to ensure…?
tear strength
1) zwick test
- safe removal
2) how far they can stretch it and have it come back to its original size
- wash is 2.6 x
three methods
1) one step
- heavy body as base with light body wash
2) prefabricate stock stray with PVS putty
- use light wash around prep and additional wash into the tray
3) prefabricate custom tray with light body wash
