Z4 is a carbon free, phosphate bonded investment for the whole spectre of C & B work.
Z4 can be used for all dental alloys as well as for pressable ceramics.
The special features of Z4 can be summarised as follows :
- After mixing, the investment is very thin flowing. This consistency allows to work with little or no vibration at all when filling the cylinder.
- Z4 works great in „ringless „ procedure allowing a free expansion control.
- The shock heat qualities of Z4 are such that they can be put in effect at every given time, meaning the cylinder can be put at end temperature up to 900° C ( 1650°F ).
- in the furnace from 30 minutes after pouring till hours after pouring.
- This allows an optimal work planning in the lab and a possibility of productivity increase without stress.
- The devesting of the Z4 after casting is extremely easy.
- Castings are very smooth.
- Z4 is universal meaning it works for all dental alloys and also for pressable ceramics
WORKING INSTRUCTIONS
Mixing ratio :
24 ml to a 100 gr. of powder
38 ml to a 160 gr. of powder
21 ml to a .90 gr. of powder
14 ml to a .60 gr. of powder
Liquid concentration:
The liquid concentrations indicated here may vary slightly depending on the alloy that is used and the casting method.
As a general rule : Raising the concentration will raise the expansion or lowering the concentration will lower the expansion.
Non-Precious alloys : 100 % liquid concentration
Palladium base alloys : 70 % liquid + 30 % water
17 ml liq. / .7 ml H2O to 100 gr.
15 ml liq. / .6 ml H2O to .90 gr.
10 ml liq. / .4 ml H2O to .60 gr.
Gold alloys < 55 % Au : 60 % liquid + 40 % water
15 ml liq. / .9 ml H2O to 100 gr.
13 ml liq. / .8 ml H2O to .90 gr.
.8 ml liq. / .6 ml H2O to .60 gr.
Gold alloys > 70 % Au : 50 % liquid + 50 % water
12 ml liq. / 12 ml H2O to 100 gr.
11 ml liq. / 11 ml H2O to .90 gr.
.7 ml liq. / .7 ml H2O to .60 gr.
Mixing time : After wetting the powder by hand, vacuum mix for 50 seconds
Working time : ca. 4 minutes
Setting time : ca. 30 minutes
Burnout : Shock heat ( rapid fire or rapid cast )
The cylinder can be put direct in a hot furnace at end temp. indicated by the alloy manufacturer with a maximum of 900° C ( 1.650° F ) ( and then eventually take the temp. higher ) after minimum 30 min. of bench setting but also hours or days after setting. The time the cylinder should remain at end temp. depends on the largeness of the cylinder and should be between 30 min. (3 ring) and 50 min. (9 ring). Holdtime + 15 min if lower temp. then 850°C.
Burnout : Normal preheating ( over nigth )
From 0° C (0° F) to the end temp. at 7 to 9° C (40 to 50° F) / min. with holding time at end temp. between 30 and 50 minutes.
Z4 for pressable ceramics :
Stratification ( crowns )
- Liquid concentration 100 % : 24 ml liq. to 100 gr.
- remove paper from cylinder after about 15 minutes.
- put cylinder in furnace direct at 850°C(1.560°F) after 30 minutes or any time later.
- preheat for 90 minutes.
Staining ( inlay / onlay / veneers )
- Liquid concentration 80 % : 19 ml liq. + 5 ml water to 100 gr
- remove paper from cylinder after about 15 minutes
- put cylinder in furnace direct at 850°C(1.560°F) after 30 minutes or any time later.
- preheat for 90 minutes.
General remarks for optimal results :
Working temperature :
The ideal working temperature of powder and liquid is between
18 and 22° C ( 66 and 72° F ). It is best to keep both liquid and powder in the same place where there is a constant temperature both summer and winter. Under these conditions a shelf life of 2 years us guaranteed and the results will be consistant and reliable ! The liquid is not frost stable !
Vibrating : Due to the flowing consistency of the Z4, vibrating is in many cases not necessary or can be reduced to a minimum. This avoids „demixing“ of the investment and leads to consistent results with smooth fitting castings.
When using metal rings do not wet the expansion paper inside the cylinder and let bench set a bit longer when Rapid cast technique will be used to be sure that the investment is well dryed before putting in furnace.
When casting gold the total liquid amount may be reduced to 22 ml in stead of 24 ml.
A 50 % indicational concentration of 11 ml of liq. and 11 ml of water can then be used.
When using Z4 for the first time we recommend to make one casting with every alloy used in the lab following the concentration indications and then eventually adapt the initial concentrations.