Protemp, Luxatemp, Telio, Integrity are some of the most popular brands of bis-acryl resins.
Acrylic resins, also known as polymetheyl methacrylate and polyethyl methacrylate, have been the gold standard for provisional fabrication for decades. I still use them in my practice to block carve provisionals when necessary. But the advantages of using bis-acryl instead of acrylic resin are numerous. They include:
(a) lower temperatures during curing
(b) low shrinkage
(c) no powder and liquid means more consistent mixtures
(d) less porous means lower bacterial contamination
(e) no nasty monomer smell
Despite these and other advantages, bis-acryl may cause you some headaches if not handled properly. Here are some tips to avoid the pitfalls:
(1) Trim with diamonds, not acrylic burs
I have found that acrylic burs generate too much action on the bis-acrylic temporary and can lead to unwanted chipping. I believe this is due to the fact that bis-acryl resin is more brittle than acrylic resin. A nice diamond bur will gently and smoothly trim excess material.
I don’t use diamonds to trim acrylic resin because the acrylic tends to stick and clog the diamond. This doesn’t happen with bis-acrylic resin!
(2) Do not have the patient bite while it is setting
As I just mentioned, bis-acrylic resin is more brittle than acrylic resin, especially while it is curing.
When I am fabricating an acrylic resin provisional, I will instruct the patient to bite down. This simple set helps further seat the curing provisional but also reduced the amount of occlusal adjustment I’ll need to do.
Do not do this with bis-acryl! You may split the curing provisional into pieces. Wait for full curing and then adjust.
(3) Apply Vaseline to cores
If you’ve just placed a core build-up on the tooth in question, care must be used when fabricating a provisional with bis-acryl. Depending on the exact material you’ve used for the core, the bis-acryl may actually bond to the core. Not good.
To avoid this, apply a light coating of Vaseline to the prepared tooth and core before fabricating your bis-acryl provisional.
Thin layer of Vaseline being added
(4) Bond before relines and additions
One of the greatest advantages of working with bis-acryl resin is that it can easily be modified with more bis-acryl or even flowable composite. Relining provisional crowns, sculpting emergence profiles around temporary implant abutments, developing pontic sites, repairing chips in the provisional, etc.
My suggestion is to place and cure bonding agent to the surface of the bis-acryl provisional that you would like to modify. I guarantee a better bond of new material to old material.
Step 1: Apply bonding agent
Step 2: Bis-acryl reline