April 05, 2012

Dental Lab Model Pouring

     This is my first pictorial step-by-step procedure for work in the Dental Lab. I don't plan on explaining why all the steps are done but feel free to ask any questions if you don't understand something. I'm starting at the beginning with model pouring and then will be moving along the stages of completing a porcelain fused to metal restoration. After that, I plan to feature procedures for implants, full gold restorations, inlays/onlays, zirconia, veneers and whatever else may pass through the lab.

Model Pouring

After receiving the box from the dentist unpack and disinfect the case.

After disinfection, prepare the models for pouring by:
     - Removing any cotton that may be on the impression.

     - Cutting away any impression material that may be creating an undercut that could lock the die stone into the impression.

     - Blocking out any undercuts in the tray with some sort of putty. I like to use some cheap stuff from the nearby Dollar Store.

Inspect the prepared die section of the impressions for any voids or bubbles to be aware of when pouring the model. These impressions have nothing serious.

Spray the models with a debubbleizer and either allow it to dry or spray out the excess with compressed air. There should be no pooled liquid remaining in the impression.

Now that the impressions are ready to be poured measure out the required amount of liquid for the amount of die stone you intend to use. Follow the manufacturer's guidelines as they are designed to achieve the required final hardness and expansion of the die stone model.

Place the liquid into a dry vacuum mixing bowl and then place on a scale. Re-zero the scale and weigh out the required die stone. No scale is necessary if you have pre-measured stone packets.

Stir the stone and water together by hand to ensure complete stone saturation then vacuume mix for the required amount of time.

Using a vibrator slowly vibrate the stone into the impression. Start at one side and flow the stone it towards the other. Watch the stone flow into the teeth so you can prevent bubbles.

Once the teeth have been poured fill the remainder of the impression with some more stone. I like to place an extra small amount of stone on the heels of the arch as they tend to sag. 

Finish up by laying a bead of stone along the top of the impression using your spatula.

If you have any mixed die stone remaining use it to pour any second pour models that you need to make.
Clean up!

Up next is model fabrication using the models you just poured.

1 comment:

  1. thank you for your post very clear and informative, what if you have a bubble on your impression do use was to fill, in school they tell u now to touch the final impression, which i think is silly