3D printing dental objects requires an understanding of the CAM software, the 3D printer, and the proper post-processing treatment of the resin. There are many ways to accomplish this, but after properly finishing the resin, it often needs to be polished (depending on the application of the printed piece). Just follow this simple procedure to properly polish the resin.
First, using a fine, pear-shaped cross-cut carbide in a slow speed handpiece, remove the printed support pins to a level with the surface of the printed material.
- Check the printed piece for undercuts or occlusal depressions and remove them with the same carbide bur, as long as they are not necessary for the fit or function of the piece.
- Dampen a rag wheel and run it on low speed. Mix a medium grit pumice with water, and with medium pressure, smooth the outside surfaces of the printed piece by placing the pumice mixture on the piece and letting the rag wheel spread it across the resin surface until you achieve an even, smooth surface.
- Do not polish the internal surfaces of the printed piece as this can ruin the fit.
- A felt cone polisher may be used if the rag wheel did not reach all of the surfaces to be polished.
- Rinse the printed piece in tap water to remove the excess pumice.
- Blow dry with compressed air.
- Remove the damp rag wheel or felt polisher from the dental lathe and replace with a dry rag wheel.
- Using a low speed, load the rag wheel with a high shine acrylic polish, by pressing the polish against the rotating rag wheel.
- Using the same slow speed, polish the printed object by running the wheel with a medium pressure against the pumiced exterior surface.
- If too much heat is developed, the polish will melt and attach itself to the printed resin material. Do not press excessively hard against the printed surface or run the motor on high speed.
- Continue to polish until you achieve a glass-like surface. This surface would be ideal for a surgical guide or a splint, since they do go directly in to the mouth.
- Scrub the entire surface of the printed piece clean using a soft brush and a mixture of liquid hand soap and water, until all of the polish is removed.
- Rinse the printed piece in running water, until the soap is removed.
Dry the polished piece using compressed air and you will end up with a well-polished resin.