The most overlooked steps of direct restorations

Direct restorations are routine for most dentists. However, some routines have sacrificed vital steps in the interest of time management, which can lead to poor results.

Before passing judgment on anyone too harshly, understand that these omitted parts of the process are often small and perceived as insignificant or even a question of personal preference. But the fact is that the impact of these small steps can have big implications for the success of the direct restoration.

Achieving proper isolation

Dr. Daniel Poticny, DDS, who practices in Grand Prairie, Texas, identifies isolation as the most common area dentists ignore, specifically in adhesive dentistry. Contaminants like blood and saliva can result in post-operative sensitivity, marginal leakage, diminished bond strengths, and composite or amalgam fractures later.

Creating a field that separates the teeth from the mouth is the most reliable way to get a positive result with adhesion dentistry. He explains that isolation is perceived “as just one more thing that they have to do to get it done” and that patients don’t like it. However, it is to the contrary.

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“There are streamlined methods for isolation that they can use. If doctors would use them more routinely, they may get a lot of enjoyment out of doing those restorations because they can complete them probably in significantly less time and maximize the outcome as a result,” Dr. Poticny says.

Dr. Suzanne Haley, DMD, PC, who practices in Saint Simons Island, Ga., agrees that creating a barrier, or isolating the restoration, is an area in which many clinicians cut corners to save time.

“A lot dentists don't realize if you don't isolate the restoration that it is going to become contaminated and that's going to lead to a faulty restoration,” she says.

Isolating with a rubber dam has been the standard of care for a hundred years, but few doctors like using them once they leave dental school. Dr. Poticny suggests having the assistant place them or trying improved products, such as a HandiDam^® by Aseptico minimally with a split dam technique, which can provide 90 to 95 percent of the isolation needed for direct restorations. Dr. Haley suggested Isolite^® for creating the required barrier.

Following the product’s directions for use

Dr. Jason Watts, DMD, who practices in Cape Coral, Fla., asserts that some clinicians do not know the proper procedures or instructions for their material. Moreover, they use them in an improper sequence, which can result in a significant amount of post-op sensitivity and other problems with the restoration. The challenge, Dr. Watts says, is that dentists don’t always see what products their team orders and don’t realize the materials have changed. They proceed as usual and think they are getting the same results.

“On the surface, the dental material might look perfect. But if doctors took a second to X-ray their work, they would see there are either voids or very bad contact,” Dr. Watts says. “They're trying to save time and steps, so they rush through it, but the materials can't be rushed through.”

Dr. Poticny agrees that doctors would benefit from reading the instructions for the application’s materials and then following them, in that order.

“Post-operative tooth sensitivity, which is a frequent complication, is generally a technique issue that doctors often try to solve by using extra products which may or may not be compatible with their own materials. This unnecessarily complicates and often violates manufacturer’s own recommendations for their use and potentially diminishes the outcome as opposed to improving it,” he explains.

Some dentists mix and match their products to cut costs, but Dr. Poticny advises using mated systems from the same manufacturer that they internally test and support.

“Researchers independently test and compare products implicitly following manufacturers’ recommendations, and dentists should do the same. Otherwise you are essentially experimenting on your patient and should not expect them to cover your back if or when it is needed,” Dr. Poticny says.

Up next: More mistakes to avoid when doing direct restorations...

Allowing time to achieve optimal bond surface preparation

Dr. Marc Hayashi, DMD, is an instructor in restorative dentistry at UCLA’s School of Dentistry. He believes that with traditional etch and rinse dental bonding agents, dentists often over dry the tooth surface. Desiccating the dentin surface too much is one of the big causes of restoration failure and eventual post-op sensitivity.

“If you're using the total-etch system, most practicing dentists tend to rush through and over dry after etching, so the dentin surface becomes desiccated.  Then, the bonding agent does not penetrate as well. So, the bond strength diminishes and post-op sensitivity can occur,” Dr. Hayashi says.

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Dr. Hayashi acknowledges that achieving the balance between too dry and too moist is a challenge. His students determine whether they have achieved the balance between the two states for their bond with a shear bond strength test exercise. “The students get to see how dry is dry and how moist is moist,” he explains.

Stripping the tooth prep surface clean

Dr. Haley recommends using chlorhexidine on the bonding surface before the bonding agent is applied. Eliminating microbials or other contaminants will set up the direct restoration for its best chance of success.

“Wait about 30 to 45 seconds and let it sit there and then clean it off. You stripped the tooth surface of any bacteria, any blood, any saliva, anything that may interfere with the bonding process,” Dr. Haley says. “That's something that doctors don’t always do, but it makes a huge difference for the overall success of the bonding.”

Dr. Hayashi agrees that using chlorhexidine is crucial to getting the best bond possible. It can help manage the denatured collagens and proteins that result from the etching process. The proteinases in the tooth can become activated and work their way to the interface over time, damaging the hybrid layer. Using chlorhexidine solutions, such as Cavity Cleanser (Bisco) or Consepsis^® (Ultradent Products), can counteract this degradation and improve the bond durability.

“What the chlorhexidine is doing is adhering to the tooth,” Dr. Hayashi says. “It's acting like another primer and re-wetting the collagen. It allows your subsequent bonding agent to bind to the tooth, into the dentin. Chlorhexidine is a longer acting chemical, so once it's in the tooth, it stays there and it preserves its action over a longer period.”

Dr. Haley and Dr. Hayashi say another option is applying GLUMA on the prepped surface. In addition to mitigating microbial activity, it also desensitizes the tooth.

“GLUMA is interesting in that it does both; it's a desensitizer and it also has this antibacterial effect. GLUMA has also recently been shown to mitigate MMP [Matrix Metalloproteinases] activity as well. But there has not been as much research on this aspect of GLUMA as compared to chlorhexidine,” Dr. Hayashi explains.

Considering the best materials for the job

When it comes to direct restorations, all materials are not created equal, and they certainly aren’t intended for all cases. It’s incumbent on the dentist to determine which material will get the best result. For Dr. Poticny, he would recommend that clinicians “consider the newer generation of bulk fills for posterior teeth, which are a significant development with respect to composites.”

In the past, the larger the increment of traditional composite material placed, the more likely once polymerized it would strain the adhesive interface and/or the tooth itself due to shrinkage of the material. Additionally, incomplete polymerization can occur in deeper areas where light intensities begin to drop off at around the 3 mm mark. Cumulatively, issues such as micro cracking in tooth structure, margin staining, leakage and voids were common findings. Hence, many clinicians instituted “layering or sandwiching” techniques, which while helpful to a degree, involve more time and are not error-proof.

Dr. Poticny thinks the latest bulk fill materials have come a long way in streamlining the procedure for placing and contouring direct restorations. He worked with 3M’s FilTek™ Bulk Fill Posterior Restorative, which will cure up to 5 mm, and it looks as good to him as his normal composite.

“For posteriors, it’s one of the best-looking materials on the market for this class of product,” he says. “I've even used it in select anterior situations.”

Dr. Watts likes using sectional matrices for direct restoration work to recreate the perfect contact, an area where conventional matrices often fail. A conventional matrix is an easy, one-step process that wraps around the tooth, but per Dr. Watts, it creates a poor contact.

“I don’t care what they say; food will get stuck underneath the restoration, whether it’s from going underneath the contact around the tooth and in the embrasures or they wind up polishing it too much and there’s not enough contact to begin with,” he says of the restorations resulting from the use of conventional matices. “Just because it looks good on the outside doesn’t mean the press is good. There’s a lot of air space that’s trapped underneath, causing imbalances to the nerves in the dental tubules, which can then cause the patient a lot of post-op pain.”

Dr. Haley also believes that dentists could think twice about attempting extensive restorations. Conserving the tooth is admirable, but not if it doesn’t work. She advises dentists to consider indirect restorations when restoring four or more surfaces.

"You might think you're doing the patient a favor by not doing a crown on everything, but the case might require it,” she says.

Our experts agree that more attention to these areas of direct restorations can create better outcomes for patients. For Dr. Poticny, it comes down to the right products from reputable manufacturers.

“Isolate, follow manufacturer’s instructions and improve your technique, which makes for predictable outcomes, eliminating the need to experiment. Look at bulk fills that reduce procedure time by 30 percent with no apparent shortcomings in terms of outcomes functionally and now esthetically,” Dr. Poticny says.