An alloy alternative

March 21, 2012

Bench Mastery: Handling Titanium As laboratory technicians, we are constantly made aware of new products and materials, and are subjected to much of the same marketing as dentists. However, we are in the unique position of having to fulfill our dentists’ requests to implement these new materials and discern what is hype and what works well. At the same time, now more than ever, we are under increasing pressure to keep costs down.

Bench Mastery: Handling Titanium

As laboratory technicians, we are constantly made aware of new products and materials, and are subjected to much of the same marketing as dentists. However, we are in the unique position of having to fulfill our dentists’ requests to implement these new materials and discern what is hype and what works well. At the same time, now more than ever, we are under increasing pressure to keep costs down.

Add to this the tumultuous gold market today, and it’s no wonder that we fear our bottom line shrinking. Offering a lower-cost noble alloy as an alternative to more expensive high-noble alloys for PFMs is an important option, but still leaves the alloy cost per crown inconsistent.

Enter titanium

Titanium is lightweight, extremely strong and very biocompatible. Although I wouldn’t categorize titanium as a “new material,” it is now more attainable and easier to use as a crown and bridge alloy. In the past, using titanium in PFMs was not an easy feat, as anyone who has ever tried to cast it will attest. Titanium gives you the ability to change the workflow in your lab by allowing the CAD/CAM fabrication of single copings and bridge frameworks as opposed to traditional waxing and casting.

Additionally, it gives you a fixed alloy cost per unit, which allows you either to charge a fixed price for the alloy per crown or structure pricing to include the alloy in the price of the crown, regardless of its size. Labs choosing not to invest in a scanner and software can still use titanium and reap similar benefits by simply partnering with another lab and outsourcing the scan and design steps. Although with the speed that technology is transforming our industry, it’s becoming difficult to imagine any lab without some type of scanning ability.

With titanium, you pay a fixed price per milled coping or pontic regardless of the size or weight. The actual price a lab pays per coping will differ depending on how you acquire your titanium frames, as labs that can scan/design their own understructures will most likely pay less per unit than the ones that choose to outsource these steps.

As with zirconia, there are different grades of titanium available today of varying quality, making it important to seek out a reliable source. For this article, I will only discuss the materials I use to produce titanium PFMs at Ziemek Dental Lab. We use titanium alloy from Nobel Biocare, which is a high-quality Grade 5 titanium, and I stack them with GC Initial Ti porcelain from GC America. We have been extremely happy with both of these companies for their excellent products and outstanding support and customer service. Special thanks to Rick Sonntag of GC for all his help while I was getting off the ground with Ti.

Basic rules

I hear quite a bit about how difficult it is to integrate titanium into a lab, and how tricky it can be to work with. Incidentally, I hear this mostly from labs that have never stacked a titanium crown, and I haven’t found this to be the case. There are a few basic rules that I follow when working with titanium.

I always use a dedicated carbide bur for metal finishing to avoid cross contamination of our other alloys, which is no different in theory than working with non-precious alloys for Maryland Bridges, etc. I would recommend dedicating a work station exclusively for it; however, I haven’t needed to do this as of yet. I just keep my work area clean, use a dedicated bur, and don’t have any issues with cross contamination.

Titanium builds an oxide layer by sitting at room temperature for about five minutes, so you don’t fire it in an oven to degas. This is a bonus in my opinion, as five minutes sitting at room temperature while I do something else is a quick, easy degas cycle.

Before you opaque your coping, you’ll need to blast it with 125-micron aluminum oxide to really roughen up the surface texture and also apply a bonder layer; again, not a big deal. After firing the bonder, the alloy is a bit darker gray than our noble and high-noble alloys, so I use a bleach shade for my first opaque application. I also recommend that our dentists cut a porcelain margin prep to avoid any dark line at the gingival.

Other than these differences, I stack it just like any other alloy we use and have been satisfied with the outcome. I would follow the instructions provided with the porcelain kit you choose to work with. I only use GC porcelain for our titanium PFMs, and subtle differences may exist.

Building the PFT crown

01 We use our NobelProcera scanner to scan the model (Fig. A) and design the copings (Fig. B).

02 Two to three days after submitting the designed file, we receive the milled titanium coping from Nobel (Fig. C). Because the coping is milled, the thickness is set at 0.4 mm and requires minimal finishing.

03 After the sprues are removed, the fit is checked and the margins are carefully finished (Fig. D).

04 The sprues are finished down using a carbide bur, and contour is refined if needed. I go over the entire coping to create a more-retentive surface texture (Fig. E). Again, special care is taken to use a dedicated bur so there is no contamination amongst our different copings/alloys.

05 The coping is blasted with 125-micron aluminum oxide at a 45° angle to prepare the surface for maximum adhesion (Fig. F).

06 The coping is steam cleaned and allowed to sit at room temperature for five minutes to build an oxide layer.

07 I apply a thin layer of the Initial Ti Bonder and fire it (Fig. G). After the bonder is fired, the coping is quite dark (Fig. H). I nullify this by applying a bleach white opaque shade for my first opaque layer, and do a porcelain margin whenever possible to avoid a gray line at the gingival.

08 I apply my subsequent opaque and opaque modifiers in the desired shade (Figs. I and J).

09 I do my buildups as usual with GC’s Initial Ti porcelain (Fig. K).

10 I contour the crown (Fig. L), glaze and add stain for any desired characterization (Fig. M).

The finished crown is ready to deliver (Fig. N).

Many dentists and laboratory technicians alike are already very familiar and comfortable with titanium when used for custom implant abutments, bars, posts, etc. Time will tell if this alloy achieves the same popularity for crown and bridge applications. In the meantime, labs should experiment with it and decide if titanium can improve their workflow and be beneficial to the all important bottom line. I am here to say it can do both, and also is surprisingly easy to work with.

About the author

Jamie Stover is Manager of Ziemek Dental Lab, a high-quality fixed restorative lab located in Olympia, Wash. His focus is using his experience at the bench as a technician along with new technology and materials to provide dentists with highly esthetic restorations, while keeping them on the cutting-edge of dental technology. He can be reached by calling 360-943-6071 or by e-mailing info@ziemekdentallab.com.