Terri Lively

		If you need removable full or partial dentures, should you order them from an overseas lab? Travis Zick, President of the National Association of Dental Laboratories (NADL), says you can, but be sure that you know what materials they are using.

		“The biggest concern working with a lab outside the United States is not knowing 100 percent what's in that restoration or that prosthetic device that you get back,” Zick says.

		Many of you might be thinking, ‘Well, that’s okay. I use a local lab, so this doesn’t apply to me.’ When you place an order for dentures with the lab, they make it for you.

		Zick, who is also Vice President and Chief Operating Officer of Apex Dental Laboratory Group, says many dentists don't know overseas labs made their restorations.

		“There's a lot of domestic labs that send work to other countries that don't disclose it to the doctors,” Zick says.

		The percent of work imported from another country and sold in the US peaked somewhere in the mid 40

 percentiles during the Great Recession a few years ago. Zick says that number has come down and last year, it was in the mid-30

		“But it's still a third of the work sold in the United States that was produced elsewhere,” Zick says.  “I don't think a lot of dentists realize that.”

		Part of the reason you might not know your work is produced out of the country is that few states require dental labs to disclose it to you. There is less governmental oversight for lab operations than most people realize.

, the state governments that require dental labs to disclose the Point of Origin for your restoration are:

	Of these states, all but Texas require a material disclosure as well. However, most states do not require your lab to tell you the restoration was produced out of the country-or what is in it.

	“The bottom line is a lot of labs are able to do things that they don't disclose or don't want to disclose,” Zick explains.

	Zick says the only advantage typically to working with an overseas lab is price.  Labor costs are lower than the US in most countries, so labor-intensive products, like removable dentures or partials, have a significant price difference.

	Working with overseas labs has a couple of significant cons as well. One of the downsides per Zick is the longer turnaround times. With the shipping and potential customs hang-ups and other related issues, it’s going to take longer to go and come back. However, that isn’t the worst of it.

	The concerns about what’s in the restoration exceed esthetics or function. The NADL has done blind tests in the past of materials purchased online from other countries. Zick says there are documented instances in the United States of work that's come in from other countries that contained lead or had radiation issues.

	In 2008, an Ohio television station tested eight crowns made in a Chinese laboratory. The crowns contained 210 parts per million of lead.

 Crowns should not contain lead at all, according to the American Dental Association (ADA). Moreover, the US set the acceptable lead level 

 at 90 parts per million, and toys don’t go into the oral cavity (at least not all the time). However, the FDA and the Centers for Disease Control and Prevention (CDC) said 

that the lead in crowns was not likely to cause a health risk

	Neither the ADA and the CDC have enough 

 to suggest that your patients are in danger from dental restorations made overseas, according to the Buffalo News. However, they cite a 2008 study that found unacceptable levels of lead in some crowns made in China.

	Andy Jakson, the owner of the Evolution Dental Science Lab in New York, was working with a lab in China that he had toured personally back in the early 2000s. As part of their partnership, he sent them FDA approved materials for his restorations.

	However, he grew suspicious about the restorations he was getting back. He had the Chinese lab’s restorations tested and learned that the Chinese lab did not use the FDA-materials he sent. Later, he learned the lab had sold his FDA materials on the black market and made his restorations with other materials.


	While this incident is one lab owner’s experience and not an indictment of all overseas labs, it may be enough to give clinicians pause. In Jakson’s case, he had no recourse against the lab in China.

	“Those are concerns. You just don’t know. You are not 100 percent sure what you are getting,” Zick says

	At that time, Zick says the product mix and activities in domestic labs on the fixed side, were still metal-based. Labs produced many porcelain-fused-to-metal (PFM) crowns and full-cast crowns, which were still labor-intensive.

	“So, doctors and labs were able to send work over to China, Vietnam, or some other countries to get those products with significant labor savings,” Zick says.

However, starting between 2012 to 2015 and forward to today, the product mix and the demand for products on the fixed side changed direction drastically, Zick says. The industry is moving away from metal-based crowns and PFMs to ceramic crowns, Zirconia, and lithium disilicate, among others. These crowns are less labor-intensive and more technology-driven. When you add in the advantage of working with domestic labs regarding turnaround time, Zick explains, the US-based labs could compete on price and bring some of that business back to the US.

	“Between material costs and utilizing technology that reduces our hands-on time at domestic labs, we're able to offer more competitive pricing on those products,” Zick says.

	An area where they still struggle to compete is with removables. While many labs are milling and 3D printing digital dentures, it is still not widely accepted or used. Today, Zick believes there are still limitations to the technology. However, in the next two or three years, there will be an increase in digitally produced removables, which will reduce the labor and hands-on time for those products.

	“We're already doing it with a lot of our partial frames. A lot of those now are milled, and the metal frames are even 3D printed. So, we've been able to introduce some technology there. But up until two or three years ago, all the technology advances in the lab business were focused on the fixed side,” Zick says.

	Digital technology is focusing on removables and implants to reduce the labor involved in production techniques.  However, part of the reason is a lack of talent in the lab industry for these products. Zick says they have the same number of technicians they did 15 years ago, but the demand for their services is much higher. Technicians who are experts in removables have suffered even higher decreases in the talent pool than general lab technicians.

	“Denture technicians are becoming a lost breed, and that's driving us to utilize more technology,” Zick says.

	However, there are significant disadvantages to working with an overseas lab for full dentures. Dentures take multiple appointments to ensure they fit and function properly. If the prosthesis goes back and forth to a foreign lab a couple of times, it could take months instead of weeks to deliver the final product.

	“On top of that, communication is where a lot of the real barriers come in. If you have to talk to the technician about the case and work together, it can be a real challenge,” Zick says.

	Few dentists are sending their lab work overseas directly, Zick says. Most of the overseas work goes through a domestic lab, and some labs will tell you, but others will not. Zick advises dentists to demand lab point of origin and material disclosures on everything that they do, whether it's the denture or a crown.

	“Tell me where it's being made, who's making it, and what's in it. Dentists need to demand those things,” Zick says.  “Now, in several states, that's law. That's a requirement. But in the majority of states, it's not. “

	Furthermore, Zick says, there are certain “tells” if the lab is not being honest. The most obvious is the turnaround time. So, if a lab tells you it's going to take two weeks to get you a setup, it is probably not being done in their lab, Zick says. The second one is the price.

	“Denture technicians in the United States are not cheap. So, if you're getting a denture, that seems like it's too good of a deal, it probably is,” Zick says.

	As president of the NADL,  Zick says it is crucial to work with certified dental technicians (CDT) and certified dental labs (CDL) in the US rather than overseas labs.  He encourages dentists to seek out certified dental labs in the US, DAMAS (Dental Appliance Manufacturers Audit System) labs or ISO (International Organization of Standardization) labs. These labs and technicians have earned accreditation and have quality systems in place.

	“They know the basics of what they're doing, and they're following proper regulation, protocols, and procedures,” Zick says of accredited labs.  “There's a lot of advantages to working with quality, well-trained domestic dental technicians, especially a CDT that can provide local service, local support and work together, collaboratively on patient care.”

	To locate a CDL in your area, visit the tool on the 

 Howard, Lee. “Lead in Dental Work Prompts Fears About Chinese-Made Crowns, Bridges.” www.Today.uchc.edu. From Article in 

https://today.uchc.edu/headlines/2008/apr08/dental_work.html

 Tan, Sandra. “Were your dentures, crowns made in China? Law would require disclosure.” Buffalonews.com. 11 July 2017. Web. 6 August 2019. < 

https://buffalonews.com/2017/07/11/law-give-patients-info-dental-crowns-bridges-made/

Articles

Overseas labs can make dentures affordable, but dentists learn quickly that you get what you pay for. 

Should You Order Dentures from Overseas?

	Dentures are labor-intensive and time-consuming prostheses for both the lab and the dentist. Our lab expert shares some insight on ways to ease the burden for both of you.

	The most labor-intensive and time-consuming dental prostheses are dentures, for both you and your lab. With more steps and less margin to work with, dentures can also be frustrating. We spoke with a lab expert to get insight on what could make the whole process more comfortable for all involved.

	Josh Gall, General Manager of Axi Dental Lab, says getting the correct bite registration is the most significant challenge for both dentist and lab.  The lab needs the correct bite in a comfortable vertical for the patient to set dentures. Plus, both the lab and the dentist want to ensure that the teeth line up with the midline.

	“There’s a lot of little things that come into play, and yes, the whole, ‘Measuring twice, cut once,’ and ‘It's all in the planning,’ and all of those clichés work for this situation,” Gall says.

	One of the trickiest things is when the lab doesn’t get adequate bite registration back from the dentist. However, Gall says he understands why bite registrations can be less than optimal at times, especially for an existing edentulous patient who is ordering a new set of dentures.

	“How do you take an accurate bite on somebody that has no teeth? How do you articulate something that doesn't have anything opposing it? Because they're not going to bite gums-to-gums, if you will,” Gall says.

	There are some golden rules when it comes to creating a denture concerning ideal spaces and openings for patients. However, for existing denture patients that have been in a denture for a long time, there are other biological factors at work, Gall says. There could be bone resorption or the loss of vertical because their bite collapses over time.

	“How do you accommodate that?  How do you get them back to where they were before they started that previous set of dentures?” Gall says of the dentist’s challenge during bite registration.

	Also, there could be corrective factors at work. The dentist might adjust the opening there because of temporomandibular joint (TMJ) issues or jaw relationship troubles.

	“So, I get it. It's not the easiest thing for the dentist. We try to give them all the tools they can when we start to make that job as easy and predictable as possible,” Gall says.

	A Disclaimer & Problems with Poor Bite Registration

	Gall hasn’t had a significant issue with resets on denture prostheses. He feels fortunate to work with experienced dentists who give his team the proper indication and the right opening.

	However, it isn’t always perfect. Sometimes, the problem doesn’t stem from the doctor at all. Sometimes it’s the patients who don't know where they are supposed to be with their bite.

	Gall gives an example of a worst-case scenario where the patient bites one way on a Tuesday but bites differently at the try-in. So, the lab moves all those teeth to the new bite. At the next try-in, the bite is off again, only this time maybe the teeth aren’t touching the way they were intended or are off the midline. Now, the lab resets again. The process is trial and error.

	The bite problems in Gall’s example do not happen every time. Most cases he receives are excellent., and he has only had a couple of patients that had multiple resets.

	However, when there have been multiple resets, Gall and the team try to figure out how some dentists have improved bite registrations and, as a result, enjoy more predictable outcomes.

	Following are tips and tricks for different bite registration problems. Gall says that taking the extra minutes to do these things could save hours of chair time and additional visits that cost you money.

	Double and triple check the bite and occlusion record before sending it back for a reset.

	In the worst-case scenario he describes, Gall wouldn’t attribute the problem to a lack of skill on the part of the dentist. It could be that what feels comfortable for the patient today doesn't feel the same the next time.  Gall says if the dentist knows it's a tricky patient and the lab has done more than one reset,  taking the opportunity to double and triple check the bite and occlusion record could help. 

	“So, some dentists maybe don't take the time to do that. Maybe they just put it in kind of visually, line things up and think, ‘Okay, that's great.’ Then, they send it back to us, we reset it, and it's off again,” Gall says.

	Gall says some dentists have the patient put the dentures in and then swallow. This activity tends to put their jaw relation in the most optimal, comfortable centric occlusion point that works. 

	Another suggestion is taking some of the teeth off the try-in prosthesis. Then, instead of trying to get all of it perfect, you can try to get the bite correct on the front teeth, for example.

	Once you remove some of the teeth, the dentist could put the try-in back in, have the patient swallow, and see if the patient can get into their “natural bite.” Sometimes in difficult cases, Gall says, the only way forward is to take a step back.

	Gall says you shouldn’t feel bound by the height the lab has given you. When taking the bite registration between the wax rims, examine it to see if you should shave some wax away because the patient’s open a bit too much.

	“If you don’t feel that’s right for the patient, trim a little wax off of there and maybe use a little bit more of the bite registration material,” Gall says, adding that the height adjustment helps the lab make a better fit.

	“Perpendiculate” in the occlusal rim

	He also suggests using Q-tips or sticks to line up the midline. Put two of them in a crossed perpendicular pattern to show the midline.

	“It shows us that you lined up the midlines and have a horizontal plane that you want to set to,” Gall says of the perpendicular indication of the midline. “Taking a little extra time on that first occlusal rim step would be the best trick that I could recommend.”

	Getting adequate bite registration is a significant challenge of denture production, but it is hardly the only area that can affect the outcome of the prosthesis. Here are a few things outside of the bite registration that you can do that make a big difference to your lab.

	Give the lab more details about the person who will wear them

	Gall isn’t suggesting you send the whole patient record or anything that would violate HIPAA regulations. However, knowing the patient’s age and whether this is their first set of dentures or a replacement makes a difference in how the lab sets up the angle of the teeth.

	“If they had been in dentures for a while, you want a passive, flat-plane occlusion that is very easy for them to move around in,” Gall explains. “Somebody newer to dentures or a younger patient, we could use a little steeper angle on the teeth and give them more intercuspation to chew with.”

	Have conversations about upgraded removable prostheses

	Gall encourages dentists to be more open to doing a preliminary evaluation of the case before determining how to proceed. The lab can help patients who have been in dentures for a while improve their denture retention and restore their smile, he says.

	Implant-retained dentures or “rebuilding” the ridge with a bar-type denture increases the height and can aid denture retention. It also addresses the sunk-in appearance long-time denture wearers often suffer.

	“We're adding a bar in there to restore some of their height and get their jaw back open a little bit and give them a more full-face look again,” Gall says.

	Incorporating implants with removable work is an option for many cases. Moreover, many clinicians can place the implants themselves using today’s technology, which can streamline the process when compared to involving a third-party surgeon.

	“Be open to working with their lab, whomever it may be, to pick the best-suited option for that patient,” Gall says. “Instead of just making a new plastic denture, maybe spice it up a bit and do an aesthetic enhancement while restoring with a better functional appliance for them.”

	Take advantage of advances in denture fabrication

	Along the same lines as the new ways to retain removable dentures, Gall says dentists should consider the new ways to fabricate dentures. Digital dentures have improved a lot and continue to make new breakthroughs.

Up until now, digital dentures had some drawbacks on the material side, Gall says. The materials used in digital fabrication were more brittle than the traditional acrylics that labs use. However, that has changed.

	“Some of those traditional manufacturers have entered the digital age and provide their materials to support a digital workflow,” Gall says. “Now, I could mill a denture today out of a material I trust, like a Lucitone 199.”

	Another early drawback with digital fabrication was that scanning technology was not sufficient. Scanning soft tissues have always been an issue. However, per Gall, scanning technology is also much better.

	“Intraoral scanning cameras these days can get a much more accurate scan of soft tissue, something that you could trust is going to be accurate enough to build a denture on, and that’s going to be comfortable for the patient and retentive, all from a non-physical intangible style of workflow,” Gall says.

	While digital dentures are a little scary for some dentists, those who embrace technology enjoy many benefits. They can use a digital scanner and send the file without taking physical impressions. Gall says the lab could then produce a digitally mocked-up denture that could take a bite, as well as check tooth and mold size in one visit, reducing the number of visits needed for dentures and speed up the chair time for them, too.

	“It’s up to the lab to be familiar with those options,” Gall says, “but the dentist should get a little experience under his or her belt, too.”

	There are drawbacks still, of course. Not everyone is using the technology for dentures, and the costs are still high for a fully digital workflow. Also, it’s new, and it can be challenging to get used to when you have been doing it the old way. However, Gall says that will change in time.

	“Acknowledging the technology can also help improve this whole process for everybody,” Gall says.

Dentures are labor-intensive and time-consuming prostheses for both the lab and the dentist. Our lab expert shares some insight on ways to ease the burden for both of you.

What Your Lab Tech Wishes You Knew About Your Denture Orders

	Composites are expected to last around ten years. Breaks in the material and secondary caries often contribute to their failures. Polymerization stress contributes to these failures.

	As a result, researchers want to find a way to reduce polymerization stress generation in composite materials. A new study published in 

 earlier this year indicates thioruethane-modified filler interfaces can do that.  

	Polymerization stress is a common problem in 

. For direct restorations, the composite material bonded to the tooth surface during polymerization shrinks. The shrinkage pulling on the bond creates shrinkage stress, which contributes to gaps at the margin.  

	The marginal gaps allow bacteria and saliva into the area and start the clock ticking to restoration failure. If there was a way to reduce the polymerization stress caused by shrinkage of composite materials during curing, then it could have positive effects on the restoration’s longevity. 

“Toughening of Dental Composite with Thiourethane-Modified Filler Interfaces”

 that suggests adding thiourethane-silanized inorganic fillers to resin composites reduced stress by 35 percent in composite materials.

 Also, these thiourethane-modified composites doubled the mechanical properties of the material.

	The following summarizes the study from who the researchers are to how they did it to what they discovered.  

Related reading: How you can make your composite restorations last longer

, Department of Restorative Dentistry, Division of biomaterials and Biomechanics, Oregon Health & Science University, Portland, Oregon, USA â¨

, UNINGA, Maringa University Center, IN Maringa PR, Brazil â¨

, Department of Restorative Dentistry, Division of Biomaterials and biomechanics, Oregon Health & Science University, Portland, Oregon, USA â¨

, Department of Restorative Dentistry, Division of Biomaterials and Biomechanics, Oregon Health & Science University, Portland, Oregon, USA â¨

Trending article: Light curing: What you can't afford to be in the dark about

	Why did they test the thiourethane-modified filler interfaces? 

	Reducing composite polymerization shrinkage and the resulting stress would decrease one of the most significant problems with the material. The researchers cite several studies that reported adding a small amount of thiourethane oligomers (polymers with a low molecular weight that have fewer units that repeat and whole physical properties are associated with the length of that chain) to the matrix of resin composites reduced stress by 50 to 60 percent, as well as increased the resistance to fracture.

	The only drawback was that if you add too much of the thiourethane oligomers, it makes the material thicker (or even too thick), which changes handling for dentists. Also, concerns exist that if you put in more than 20 wt% of thioruethanes, it could decrease the elastic modulus.

	To overcome these concerns, the researchers chose to silanize the surface of the inorganic fillers with thiourethanes and see what happens to the mechanical properties and the rate of change for the chemical process during curing. By attaching the thiourethanes to the filler particles rather than replacing them, researchers posited that the thioruerthanes’ presence should not affect the monomer matrix’s viscosity. 

	1. The thiourethane-oligomer-silanized filler particles can distribute through the resin matrix without causing problems with polymerization and depth of cure. â¨

	2. It will improve resistance to breaking and polymerization stress in the finished restoration. â¨

Continue to the next page to see how the tests were performed and what the researchers discovered.

	• They created the thiourethane-modified resins, and prepared the control groups.  â¨

	• For fracture toughness (KIC), the researchers used the single-edge notch beam method. They made samples in a split steel mold with a 2.5 mm notch in the middle and photoactivated for two minutes per side using a radiometer to ensure they had the proper irradiance (800mW/cm

).  They tested using the universal test machine.  â¨

	• For polymerization stress, researchers use a cantilever beam apparatus. The cylindrical samples were light-cured for 40 seconds (at 280 mW/cm

). Then, researchers recorded the data digitally for 10 minutes to calculate the shrinkage. â¨

	• For degree of conversion, three specimens were laminated between glass slides, cured, and measured with near-infrared spectroscopy.  â¨

	• For polymerization kinetics, researchers observed samples for 300 seconds at two scans per spectrum with 4 cm

	• For depth of cure, specimens were made in silicon molds, photocured, and stored for seven days. After a week, they embedded them in slow-curing epoxy resin and cut them to measure the depth of cure.  â¨

	• For viscosity, they measured unpolymerized resin in a cone-plate rheometer.  â¨

Related reading: The evolution of resin composites for direct restorations

	• Thermogravimetric analysis revealed that the thiourethane fillers had 48.5 percent more organic content than the control groups. â¨

	• KIC increased with the thiourethane-silanized particles, except for one that had similar values to the control. â¨

	• Polymerization stress decreased significantly with the thiourethane-modified composites, except two that had similar values to the control. â¨

	• When compared to the controls, there was not a significant change to the depth of cure or an increase in the viscosity when researchers added thiourethane-silanized filler particles to the material. â¨

	• Rate of polymerization was statistically different. At the onset of vitrification, the DC at Rp max (degree of conversion at a rate of polymerization) was 7 to 14 percent, and highest in the groups that had benzene as the isocyanate.  â¨

	• All materials had a depth of cure 3.5 mm at least, which was the full depth of the samples. The thiourethane-silanized filler groups had similar or higher degrees of conversions as the controls. 

Trending article: How to break out of your restorative rutâ¨

	The past studies that had shown improved results for reducing polymerization stress and increasing fracture toughness using thiourethane oligomers had limitations. They couldn’t add too many oligomers or it would increase the viscosity too much, which would keep out the inorganic fillers needed to facilitate the mechanical properties of the composite restorations. The past studies suggested that silanization of the oligomer to the surface of the filler particle could overcome this limitation. The researchers for this study wanted to test it and see if they could harness the same benefits without suffering the drawbacks of adding the oligomers directly to the resin matrix.  

	When researchers added thiourethane-silanized filler groups to the composite, there was as much as 35 percent less stress, and the mechanical property values doubled. Furthermore, this did not alter the viscosity of the material and did not require a complicated photoactivation process.  

Continue to page three to see what more needs to be learned.

	One interesting finding from the research was something the results did not show. In previous studies, the addition of thiourethane to the resin matrix led to events that delayed gelation and vitrification. Specifically, the thiourethane-modified composites delay in the point of conversion where the “monomer mobility limitations hamper polymerization and, thus, allow higher final conversion and delayed modulus development, ultimately delaying and reducing stress development.”  

	However, here, researchers silanized the thiourethane to the surface of the inorganic fillers, and the reaction rate was the equivalent to or higher than the maximum rate of polymerization as the controls. At the same time, the degree of conversion at the maximum rate of polymerization was either equal or significantly lower than the controls. They also did not see significant correlations between these factors and measurements of stress. Furthermore, they didn’t see the same monomer mobility limitations with the thiourethane-silanized filler composites because they did not change the viscosity of the material.  

	In the discussion, researchers attribute these findings to the fact that thiourethane was less concentrated than it was in the composites observed in the previous studies. In other words, because thiourethane was not added directly to the matrix, it reduced the effects on these outcomes. Also, the researchers suggest that gelation and vitrification did not play a role in decreased stress observed, and it must be explained by something else. More research might reveal these explanations. 

Click here to read the entire study from 

	Composites have wonderful qualities for direct restorations. However, they have always fallen short on longevity, at least when compared to materials like amalgam. One of the main culprits that leads to eventual failure is polymerization stress caused by shrinkage during curing, which pulls on the bonded surface. If there were a way to decrease that stress, composite restorations could last longer.  

	Like all research, however, more needs to be done on this essential finding. However, this study shows promise for using thiourethane-modified-silanized fillers to reducing stress, and all the related consequences of it, in direct composite restorations. 

Composites filled with thiourethane-silanized inorganic fillers had up to 35% lower stress, study says. 

Study finds new way to toughen composite restorations

Resin composite materials are a popular restorative material, but when compared to other materials, their longevity leaves something to be desired. However, there are things you can do to make composite restorations last longer. 

Composite materials have many advantages for restorative dentistry. Most importantly, you preserve as much healthy tooth as possible when you restore caries with composite. In addition, composite restorations are undetectable because the materials blend in with the tooth. Resin composites also bond to the patient’s tooth quickly. 

That said, resin composite restorations have one main disadvantage. They don’t last as long as other fillings. 

Most experts agree that composite restorations last from five to seven years. Some say 10 years. That sounds like a decent length of time until you compare to other restoration materials. For example, amalgam can last from 10-15 years, and the same goes for ceramics and gold. 

Sure, these other restorative materials have disadvantages, too. For example, amalgam requires you to remove more healthy tissue from the patient’s natural tooth, and gold and ceramic fillings are expensive. However, when compared to the durability of composite resin, longevity is not one of their problems. 

Part of the reason composite resin restorations have shorter life spans has to do with execution. Using composite is technique sensitive and product-specific. Tim Bizga, DDS, FAGD, a private practice general dentist in Cleveland has adopted a saying that he uses when he trains in seminars and when he runs his practice: “Complexity is the enemy of execution.” 

Dr. Bizga says that however the product is formulated, the difference in the dentist’s experience often has to do with the clinical situation and the patient in the chair. Composite resin materials have many steps that are precise in their execution and that vary by manufacturer. While that isn’t a problem by itself, when you take into account that the patient in the chair could be a child or a patient with special needs, it complicates the situation. 

“Now you have less than ideal circumstances, which is what most dentists encounter,” Dr. Bizga explains. “Everybody is trying to do the right thing. It just doesn’t always work out because that’s life.”

The popularity of composite resins for restorations shows that the advantages outweigh the disadvantages in most dentists’ minds. So, what can clinicians do to prolong the lifespan of our resin composite restorations? A few things, according to our experts. Here’s what they had to say. 

Sarah Jebreil, DDS, AAACD, has a private practice in Newport Beach, California, that specializes in cosmetic dentistry. She says for both anterior and posterior restorations with resin composite, one of the most significant factors in composite longevity is isolation because of the adhesion required. 

“If you are not in a dry environment, and you have any moisture, that will definitely decrease the bond strength,” Dr. Jebreil says. 

“All resin systems to my knowledge require good isolation. That’s the hallmark,” Dr. Bizga agrees. “If you look at the case and don’t know if you can get it, you have got to have alternatives in the office.”

Of course, isolation has many challenges in the oral environment. Dr. Jebreil says that some patients have more moisture than others in their mouths. Also, the type of isolation a dentist uses can affect how dry the area is. Rubber dams are ideal but also time-consuming. Dr. Jebreil says that can mean dentists in a hurry might choose a different way to isolate that isn’t as effective as the dam. 

“There is a multitude of factors,” she explains.

 Isolation System. He says that it helps him get the isolation he needs to facilitate the bond. However, he says while Dry Shield takes care of saliva, it doesn’t help with bleeding around the tooth itself. 

One way to help with bleeding is using dental lasers to cauterize the area. Sometimes it means packing cord. However, you choose to control the bleeding, Dr. Bizga says it is essential.  

Sometimes restorations are compromised at the margins because of staining and bacteria accumulation there. One way to help prevent this situation per Dr. Jebreil is to polish the margins properly.  Margins need a smooth finish to make the surface less hospitable to bacteria and other contaminants. 

“When you are done with the restoration, you always want to check the margins and make sure they are adequately polished,” Dr. Jebreil says. 

As a dentist who practices much cosmetic dentistry, Dr. Jebreil has many cases where esthetics are a priority in the treatment. She finds that in the anterior, having an adequate prep design is vital. 

For example, when a patient has a chip in the front, Dr. Jebreil likes to design her anterior preps with a wide bevel and chamfer to facilitate retention of the material as well as protecting the enamel margins from leakage. Proper angling of the bevel is crucial depending on the type of material you are using and how you are using it. 

“If you don’t have enough surface area, the restoration can just pop right off,” Dr. Jebreil says. 

Dr. Jebreil is also a fan of maintaining the fundamentals of occlusion as well to extend the life of your restorations. The three determining factors of occlusion include the temporomandibular joint or TMJ (the posterior determinant), the teeth (the anterior determinant), and the overall neuro-masticatory system.

 They work together in a patient’s mouth to determine the occlusal relationship. Each one must complement the other to keep things running smoothly when the patient chews.

Dentists can only change one part of these three, the teeth.

 Therefore, it is essential to understand and remember the basics of how these three factors work together when practicing restorative dentistry to increase the longevity of your restoration. If any part of the restored tooth is off from the natural shape, it could create interference or excessive force on one of the determinants, which could then lead to earlier restorative failure. 

To avoid this outcome, experts agree that dentists should include an examination of the TMJ, the teeth and soft tissue, and the periodontium before you start treatment. Also, you should review all the factors involved that could influence the movements while chewing that could affect how the three parts work together.

Dr. Jebreil says another reason that some restorations do not last as long as they could is that the clinician didn’t understand the materials they were using well enough. She emphasizes that when using composite, it is crucial to follow the manufacturer’s guidelines. 

She also recommends finding the material that “works best in your hands.” When you follow the manufacturer’s guidelines that you know by heart, it makes a significant impact on the bond strength as well. 

“I always use the BISCO ALL-BOND UNIVERSAL

. I love it. I use it because it works well in my hands and I know how to use it,” Dr. Jebreil says. “But if I were to switch to something else, I would have to read exactly how to use it and make sure my team knows how to use it.”  

Dr. Bizga advises dentists to come up with a system that you have in place where you and your assistant are on the same page. Dr. Bizga says that sometimes patients comment on how well he and his assistant work together.  

“They’ll sit up and go, ‘You guys are a great team. Like, you didn’t even say a word, and she knew exactly what you wanted next,’” Dr. Bizga says. “And it does happen. Sometimes when you are intensely focused, the conversation stops.” 

Dr. Bizga says having that focus and routine allow you to rise to the occasion when you encounter difficulties. For example, if the isolation is beginning to get compromised, you can work through the procedure quickly, so you don’t suffer the consequences of that. 

“If you are efficient in knowing what step is next, that every single one counts, and you do them to the best of your ability, you can get through it,” Dr. Bizga says.  

Dr. Jebreil encourages dentists to consider the patient and the placement when choosing materials. The best chance of survival for the restoration might have more nuances than a one-size-fits-all approach.

For example, if you are working on a patient that has a high risk for caries and you are working on a subgingival restoration where you can’t get sound isolation, maybe you should reconsider a direct restoration in this case. Dr. Jebreil suggests switching to an indirect restoration to get a better seal in this case. 

Another example might be a patient who bruxes and needs restoration on the second molar. Many materials might not be suited for this placement, so choose a material that can stand up to the wear the patient will likely apply to it. 

“A lot of it is a case-by-case basis,” Dr. Jebreil says. “You should ask yourself, ‘Is this the right material for this tooth in this patient at this time?”

“We have to control moisture, fluid, and contaminants, and if we can’t do that, then you have to look to alternative materials to complete the restoration,” Dr. Bizga says. 

Dr. Bizga says some alternative materials can be glass ionomer or amalgam. However, both might not have the esthetic results you and the patient desire.  Also, in most situations, glass ionomer has a shorter life span than composite, so it may not be the best alternative if longevity is your goal.

Resin composite restorations have a shorter lifespan than other restorative materials. We talk to experts to learn how clinicians can prolong the life of their restorations.  

How you can make your composite restorations last longer

	Some patients think once they get dentures, they never have to worry about their teeth again. It is up to you to set them straight. Here’s what the experts had to say about the care and maintenance you need to communicate to patients about their dentures.

	Sometimes when a patient gets a denture, they think, “That's it for dental care for the rest of my life.” However, you know that is not the case and that their expectations for the appliance are already too high.

 dentures last between five and ten years.

 However, Raymond Choi, DDS, a mini-implant dentist and educator for Glidewell Laboratories, says many times patients hold onto them for longer than that.

	“I heard or read somewhere that the average age of dentures in America is about 12 to 18 years,” Dr. Choi says.

	So, how do you set proper expectations for care and maintenance of a denture once you deliver a prosthesis? We spoke to denture experts to see what they had to say.

	Dr. Choi says the best time to go over the expectations for care and maintenance is right from the start. He does it when he meets patients rather than when he is finished with treatment.

	“I always find that to be more effective to do it upfront. Patients are more receptive and rather than doing it at the end or afterward when they have some issues. So that's a good time or at least at the delivery appointment,” Dr. Choi says.