The last two posts have focused on utilizing shell provisionals during the restoration of an entire arch of teeth. A critical step in the fabrication of any provisional is trimming to perfect the marginal fit and create the proper embrasure form and emergence profiles. Once the provisional has been trimmed the final polish not only creates the esthetics but a smooth surface that optimizes tissue health. For many years I trimmed my provisionals with carbide burs in a straight handpiece. The challenge I ran into was that the shape of the bur wasn’t conducive to the shape I was attempting to create. The cutting speed didn’t match the work flow, and the final surface texture was rough and difficult to polish.
About ten years ago in a course I was introduced to using silicone polishers to trim provisional material after the gross bulk of material is removed with a carbide bur. The knife-edge shape is perfect for creating the incisal and gingival embrasure form. Depending on the speed of the handpiece they cut at a speed that is efficient and precise without catching or chattering. For more intricate areas you can simply dial down the speed of the handpiece. As you use the polishers, the edge gets thicker and more rounded. This shape is perfect for final trimming back to the margin, creating the facial reflective zone and the lingual concavity. I utilize two silicone polishers, starting with the more coarse green polisher and then finalizing with the pink. The final surface texture is smooth and very easy to final polish with Brasseler’s Provi Pro polishers.
I follow the same protocol to trim all provisionals as it creates both efficiency and predictability. I strongly encourage the use of bur systems, either one someone else has designed or one you personalize based on your own preferences. Recently I created my provisional block based on the series of burs I now use. The block is available from Brasseler and lists the use of each bur on the inside cover as well as the order number. 
Provisional Trimming Steps:
- Gross trim excess material with the carbide cutter
- Trimming and shaping with the green silicone polisher
- Fine shaping with the pink silicone polisher
- Surface morphology and occlusal anatomy with the finishing carbide
- Internal relief with the EF Cutter
- Embrasure form with the perforated disc
- Polish with the Provi Pro’s ( Orange before Pink)
Hi Lee
Do you use this technique for both acrylic and bisacryl ?
Jerry
Jerry,
yes it works great for both bisacryl and acrylic.
Lee