Figure 1: Looking at the prepared typodont, you can see that the case has been prepped from first molar to first molar. As with any large case like this, BioTemps are my preferred provisional treatment option.

Figure 2: In real life, the patient is probably missing a bicuspid on the right, one on the left and maybe a lateral, so BioTemps are a good choice because of the strength they provide during the temporary phase. Any time I’m prepping this many units, even if it’s just four full crowns, I will always opt for BioTemps — not just because I get them for free, but also because they look so good and can simplify the temporization process. There are times when chairside temporaries might make more sense, but for a case like this, BioTemps are generally easier and require less chair time.

Figure 3: This model shows what the patient looked like when he came in for treatment. As you can see, he has some alignment issues. Teeth #3–14 will be prepared for crowns. Before preparing, however, the model is sent to Glidewell Laboratories with a prescription for a 12-unit splinted BioTemps Provisional.

Figure 4: The model on the left is what it looks like when the lab’s technicians have prepped the patient’s model for BioTemps. Glidewell technicians are under strict direction not to remove more than a millimeter from any tooth surface.

Figure 5: Taking a closer look at the prepped model, you can see the technician was conservative with his reduction. He did mimic the occlusal surface, which is sometimes why “table-top” preps don’t work, but it’s evident that he tried to be very minimal in his axial reduction and at the gingival margin. Our technicians try to eliminate undercuts from the preparations in an effort to make the BioTemps as thin as possible.

Figure 6: Here’s a BioTemps restoration as typically ordered by a dentist. It has wire reinforcement and, for this case, spans from teeth #3–14.

Figure 14: You may have already ordered your BioTemps in one single segment, however, and might be having trouble getting a passive fit. If this is the case, the first thing you can do is something I do for every BioTemps case: request a prep guide. A prep guide is a thermoformed splint that fits over the prepped BioTemps model.

Figure 15: If I have a large BioTemps bridge that isn’t fitting, I’ll try the prep guide in the patient’s mouth to get an idea of where I haven’t prepped enough. In some cases it will fit correctly, but in others it will be touching the prepped teeth, showing me where I need to reduce more. Adjustments can then be made and the BioTemps bridge tried in again. (I don’t find that I under-reduce very often anymore since I started using the Reverse Preparation Technique, but under-reduction can happen interproximally with this technique because we don’t place depth cuts on the mesial and distal surfaces.)

Figure 16: When you try in the prep guide, however, you may find that you have reduced enough everywhere; you just don’t have draw between all of the teeth, which is preventing the bridge from seating properly. You now have three options: the first, and my preferred technique, is to blow out all of the interproximal areas on the bridge between the teeth. These interproximal margins aren’t really necessary and will be picked up in the reline; they just happen to be there because the bridge was made on the model.

Figure 17: For this technique, I use a bur to blow out the interproximal connections, turning each tooth area into a “taco crown” with a facial, occlusal and lingual shell. As you get closer to the anterior, you may need to switch to a bur with a thinner tip than I’m using here to avoid breaking through to the facial. Again, when we reline the BioTemps on the teeth, we’re going to pick up all this interproximal information.

Figure 18: Once you’ve had the opportunity to cut through all the interproximal connections, you can go back to the patient’s mouth and try in the BioTemps bridge again to see if you now have a better fit. Here, you can see the fit is somewhat improved, but I didn’t break through the anterior connections, and this is where interproximal hang-ups often occur.

Figure 19: A second option is to take the BioTemps bridge and segment it using a diamond disc (remember, the BioTemps bridge is reinforced with wire that is about the thickness of a paper clip). This isn’t my preferred approach because it can lead to a diastema, but when you’ve paid $29 per unit for the BioTemps, and the patient is counting on having some really nice temporaries when he or she leaves your office, you want to find a way to use them! Using the diamond disc, I cut the bridge into three segments: two 3-unit posterior segments and one 6-unit anterior segment. Once I’ve segmented it, I’ll use a bur to polish the cut sides, making sure to smooth out any pointy wires.

Figure 20: The downside of segmenting the bridge this way is that you almost always end up with open contacts between the teeth where you made your cuts. To fix this, I fill in the open contacts with some flowable composite after relining and then cure. I don’t want the patient getting food and plaque packed in the undercuts, nor do I want to have unesthetic spaces. The composite will adhere to the cut portions of the BioTemps because we removed the glaze from these areas during our cutting and reshaping.

Figure 21: If you try these techniques and the BioTemps bridge still won’t fit, there is one last bailout option: the second stent that I request for every BioTemps case. As I mentioned before, the first stent is the prep stent (Figure 14), a thermoformed stent that is made over the prep model. The second one is a thermoformed stent made over the BioTemps themselves. I call this the “bailout stent” or the “full-contour stent.” I take this stent and fill it with bis-acryl material (something like Luxatemp^® from DMG America [Englewood, N.J.]) and then seat it down onto the preparations in the patient’s mouth to create a chairside temporary. Because it’s made out of bis-acryl material, it won’t be as strong, have the wire reinforcement or be glazed as nicely as the BioTemps, but at least it will match the BioTemps in size and shape, and the patient will leave with an esthetic improvement over when they walked in the door.