Hotter than gold?

Titanium is becoming the new buzzword in dentistry these days. With gold more than $1100 an ounce and platinum topping out at nearly $2,000, the cost of the traditional high noble PFM crown, the bread and butter of dentistry, continues to skyrocket. This has kept laboratories and dentists searching for lower cost alternatives especially in an economy where everyone is doing some belt-tightening.

Some have switched from metal to all-ceramic, others from high noble to noble or even non-precious, and now a growing number of laboratories and dentists have turned to titanium as the understructure material of choice. Strong, lightweight, exceptionally biocompatible, radio lucent, and price stable, titanium offers all the plusses of gold without the fluctuation in price, allowing laboratories to offer fixed price restorative services. But it’s the ability of titanium to now be CAD/CAM milled that has made it a viable choice.

“The option to CAD/CAM mill titanium versus casting is one of the biggest reasons titanium is catching fire in the industry,” said Jamie Stover, Manger of Ziemek Dental Laboratories in Washington. Ziemek is working with NobelProcera, the new scanner from Nobel Biocare, to scan models, design copings and frameworks, and then send the design data to Nobel’s centralized production center for milling. Ziemek gets back the milled substructures, which are milled from a Grade 5 titanium alloy, within a couple of days, for light metal finishing and porcelain layering with GC’s Initial Ti porcelain. It’s allowed his laboratory to offer a fixed price for crowns, whether it’s a molar, bicuspid, or bridge unit, it’s all billed at the same price point and their clients like that option. The real savings Stover says is when fabricating bridges and larger copings. Because so much metal is used in the connectors and pontics, the cost of a substructure can skyrocket if constructed in high noble or noble alloy. With titanium, a unit is a unit regardless of size or weight and gets billed at the per single unit price.

Lab-to-lab outsource businesses also are experiencing a surge in orders for titanium milled substructures. Only a handful of CAM milling units can mill this metal but for the service centers offering the option, titanium milled substructures. Only a handful of CAM milling units can mill this metal but for the service centers offering the option, titanium substructures are becoming an ever-popular choice said Ryan Gillespie, Manager of Precison Milling Center . It’s actually more cost-effective to mill titanium than non-precious because of the milling blank price; the cost of a titanium-milled coping is in the same range as a zirconia or chrome cobalt unit.

For labs tapping into domestic outsourcing services and sending design data, titanium can be a nice profit center. Titanium holds an ADA classification that is higher than a noble metal and recognized by insurance companies as reimbursable to the dentist.

“Our Laboratory customer can send us a coping file to be milled in titanium for a cost of $25. That’s a big savings for labs as the typical cost of noble metal alone is $25 before they add any cost of labor. The double cost benefit comes from the ADA’s classification making the titanium crown more valuable than its noble metal counterpart.” said Gillespie. Precision Milling Center uses the ORIGIN CAD/CAM system to mill copings and frameworks from Grade 5 titanium alloy that is 89% titanium with an MPa of around 950.

It’s all in the handling

But titanium is not for everyone. Some laboratories are hesitant because titanium requires specialized handling and requires a dedicated workstation, which may not fit into the laboratory’s current processing setup. “If you do work with titanium you have to be regimented in your final processing,” said Stover. “You have to be more diligent about cleaning up the work space and work a little cleaner.” Both Gillespie and Stover suggest using a dedicated workstation and dedicated crosscut carbide bur for metal finishing to eliminate the risk of titanium particles contaminating high noble or noble copings, which will react during the degassing and opaquing production phases and cause bubbling. “It’s a similar mindset as when working with non-precious alloys,” said Stover.

Titanium coping surfaces also need more roughing up during sandblasting for a better bond so a courser aluminum oxide (125 microns) is suggested and a blast angle of around 45 degrees. The biggest difference in working with titanium is that you don’t degas in an oven. After sandblasting and steam cleaning, the coping or framework should be left to sit at room temperature prior to layering on a bonder. At Ziemek they recommend a sitting time of only 5 minutes while Precision Milling Center believes in a 10- to 30-minute “degas” phase.

“Titanium loves oxygen,” said Gillespie. “During that “degas” period the surface of the coping is reacting to the air and building an oxide layer.” But be careful. It’s just as detrimental to the final outcome to let the substructure sit for more than the allotted time than not to let it sit and oxidize at all.

Once the oxide layer is ready, you layer on a bonder, fire it, then opaque, and then stack porcelain. Stover suggests porcelain margins whenever possible with titanium because firing causes the metal to turn dark gray. He says he uses a bleach white opaque layer to mask the metal and then comes back with a regular opaque. “Sometimes we do three opaques, a white wash, then the desired opaque shade prior to stacking,” Stover said.

Several manufacturers offer porcelains specially suited for layering titanium. GC’s Initial Ti, Vident’s VITA Titanium, B&D distributes Dentaurum’s Tri-Ceram (distrubed by B&D Dental), Zahn’s Noritake TI-22, and Nobel Procera Titanium are among those available.

Titanium-based restorations may not fit everyone’s bill, but for patients titanium also exhibits unique heat transfer properties that reduce the risk of hot and cold sensitivities often experienced with conventional metal-based crowns. Better than gold? Some think so.