With the many furnaces available from numerous manufacturers, selecting just the right one can be a daunting task for any dental lab technician. There also are four categories of furnaces to differentiate from, each made to best handle varying tasks.
Having more than 30 years of component-level electronics experience, Daniel Serrago of IBEX Dental Technologies Inc., Richardson, Texas, literally knows all types of furnaces inside and out.
He’s agreed to share some of that furnace know-how with DLP. Serrago offered information about the differences between furnaces, features, specifications, latest developments in furnace technology and a check list to use before making a purchase.
After serving as a Master Radio Electronics officer as a U.S. Merchant Mariner back in 1979, Serrago maintained and repaired ships’ computer navigation, engine room automation controls and radio/satellite communications equipment.
That experience led him to establish Garland Dental Services about 16 years ago and later IBEX. Over the years, he has taken apart, fixed and put back together just about every kind of dental furnace that exists.
“As the owner of Garland Dental Services, I have repaired hundreds of furnaces of all makes and models over the past 16 years,” he said.
Furnaces are expensive and important pieces of equipment for lab technicians. Here’s Serrago’s breakdown of the types of furnaces available and the tasks they handle:
Firing Furnace — Used to vitrify porcelain, the firing furnace is still the backbone of the dental lab industry when it comes to furnaces. Firing furnaces require excellent temperature and heat rate control. They frequently fire in a vacuum environment, so maintaining vacuum also is important.
Burnout Oven — Used to “burn out” casting and pressing rings, the burn out oven is a staple in the dental lab. Because of the rings’ ability to be burned out over a broader temperature range, less stringent temperature controls are required, and the oven doesn’t use vacuum.
Pressing Furnace — Used for pressing today’s pressable porcelains and ceramics. Pressing furnaces have all the same control requirements as the porcelain furnaces with the addition of the pressing hardware and controls. Almost all of today’s pressing furnaces allow you to program porcelain firing programs as well.
Sintering Furnaces — Used to sinter yttrafied zirconia (yz), sintering furnaces are a unique class of furnace. They are required to operate at much higher temperatures than conventional firing or pressing furnaces. To achieve these temperatures, special ceramic heating elements and power control electronics are employed.
It’s all about performance
How any given furnace performs is what sets one furnace apart from another, Serrago said.
“All porcelain and pressing furnaces manufactured today are microprocessor controlled providing a variety of program capacities and features designed to make its operation easier, in theory,” he said. “While there are other differences worth noting, I believe that what truly sets one furnace model apart from another is its performance consistency, its ability to provide the technician with predictable results firing after firing. This critical factor is not determined by how many programs it can store or by where the Night Mode button is located.”
The design of the electronics and muffle is what produces predictable firing qualities, he said. And the combined performance of today’s furnace electronics and muffle designs varies greatly between manufacturers.
Bells and whistles
What features and specifications are most important is an individual choice for every technician.
“Unlike stereo systems or HDTVs, the important technical specifications defining the electronics and muffles used in today’s furnaces are simply never published,” Serrago said. “Features abound in today’s furnaces. It all comes down to personal preference. Do you truly need 200 programs or is it critical that you can place your favorite photos on the full color displays now available on some furnaces?”
Let how well the furnace consistently and predictably fires be the most important feature, he said. Then look at ease of use.
“How easy it is to program and to manipulate, edit, move, copy or change parameters on the fly?” Serrago said. “Equally important is the furnace’s dependability and the level and cost of maintenance and support from the manufacturer, especially after the warranty period expires. Some repair parts assemblies can cost upwards of 20% of the cost of a new furnace.”
Unlike buying clothes
When buying clothes or finding the latest fusion restaurant to dine at, there’s usually a new trend to consider. That isn’t the case with furnaces. Trends in furnaces have remained stable for quite some time. There really aren’t a lot of, excuse the expression, “hot” new features to boast about when it comes to furnaces.
In general, since the mid 1990s, firing and pressing furnace performance has changed very little, Serrago said. Firing accuracy, consistency and predictability has divided into two price-driven groups.
“While manufacturers on both ends of the divide have been adding features to expand ease of usability, those at the lower end have done little to advance furnace performance and narrow the performance gap with the high end furnaces,” he said. However, there have been some recent innovations in muffle and electronics designs that have produced products that have broken the traditional price versus performance gap.
