Understanding Bulk Fill Composites (Part 1)

April 15, 2022 Lee Ann Brady DMD

For years and years, we were trained to not use bulk fill composites. We were well trained to layer composites to improve the success of their longevity. For years, it was smaller layers and angled layers. What was that about? The primary issue we were trying to overcome was the shrinkage of the composite material. Shrinkage stress could destroy adhesion and fracture enamel. Another issue was depth of cure. Traditional composites couldn’t be cured in bulk. Between shrinkage and polymerization, layering became important. We would also layer to ensure we condensed the fill.

In time, scientists and manufacturers looking at this were able to alter the chemistry of the composite to alter the impact of polymerization shrinkage. When bulk fill composites first came on the market, despite what the manufacturers told me, I felt some internal resistance and it took me a while to step into the bulk fill arena. What drove me to take that leap of faith was looking into the science behind bulk fill composites.

The Science

I spoke with different scientists, from different manufacturers, and with independent scientists who created these materials. What I came to understand is that bulk fill composites are an improvement in composite technology.

The manufacturers learned how to direct shrinkage away from the bonded interface. Across the category of bulk fill materials, all these materials have a lower shrinkage stress numbers than the categories of composites that came before them. They do better at maintaining the integrity of the interfaces between the composite and dentin adhesive and the dentin adhesive and the walls of the cavity preparation.

The manufacturers increased translucency to increase the depth of cure. In general, when a manufacturer says they have a bulk fill composite, what they mean is that the depth of cure is somewhere between 4 to 6 mm. I often hear the complaint that bulk fill composites are not as esthetic as traditional composites. Each of us must answer individually for ourselves how exact and perfect we want to make the match of the composite to the surrounding tooth. Manufacturers have attempted to address this and now offer bulk fill composites that become opaquer as they cure.

Multiple Choices

Like everything else in dentistry, there are many choices. There are multiple types of bulk fill composite, even from single manufacturers, with variances in the specific depth of cure they recommend. When evaluating bulk fill composites, consider these questions:

  • What is recommended depth of cure for that specific composite?
  • Is the composited graded high enough to withstand occlusal loading and wear, or does the manufacturer recommend you use a different composite to create a 1 to 2 mm cap layer (typically, a more traditional nano category of composite)? The silver lining is that this provides an option when esthetics are of high concern.
  • Is the composite condensable, requiring you to use condensing instruments, or is the composite more flowable and referred to as self-leveling, because it flows perfectly across to perfectly fill the preparation cavity? Self-leveling composites have a chemistry that allows them to have less initial viscosity and then thicken after they have flowed.
  • Among your choices are bulk fill composites that come in small containers to go in composite guns, compules, and syringes. The less viscous, flowable composites come in a syringe that looks like a flowable and you can put a flowable tip on it.

I’ll be back with Part 2 of this blog to present more about bulk fill composites. To leap ahead, you may want to visit the Pankey YouTube channel to view the webinar I presented on this topic in 2020. You can view it here.

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E3: Restorative Integration of Form & Function

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Location: The Pankey Institute

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Lee Ann Brady DMD

Dr. Lee Ann Brady is passionate about dentistry, her family and making a difference. She is a general dentist and owns a practice in Glendale, AZ limited to restorative dentistry. Lee’s passion for dental education began as a CE junkie herself, pursuing lots of advanced continuing education focused on Restorative and Occlusion. In 2005, she became a full time resident faculty member for The Pankey Institute, and was promoted to Clinical Director in 2006. Lee joined Spear Education as Executive VP of Education in the fall of 2008 to teach and coordinate the educational curriculum. In June of 2011, she left Spear Education, founded leeannbrady.com and joined the dental practice she now owns as an associate. Today, she teaches at dental meetings and study clubs both nationally and internationally, continues to write for dental journals and her website, sits on the editorial board of the Journal of Cosmetic Dentistry, Inside Dentistry and DentalTown Magazines and is the Director of Education for The Pankey Institute.

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Using Air Abrasion for Composite Repair

March 28, 2022 Lee Ann Brady DMD

A while ago, I had the opportunity to repair a small bubble in an old composite restoration, and I got to thinking you might like to know how I use air abrasion to do this type of repair.

I don’t know how many times you see this, but I frequently see small holes in old composite restorations. In many cases, the margins look good. Everything looks good about the restoration except where there was an air bubble when the composite was placed and now there is a little hole on the occlusal surface. Food can get trapped and staining can occur in the hole, but the hole doesn’t descend into the tooth. And sometimes I see a little gap on the margin of an old composite with staining or early decay. In both cases, I don’t want to remove the entire restoration.

I use a lot of air abrasion in my practice, and in particular, I find it is wonderful for repairing old composite. I have the EtchMaster® from Groman. It’s a little handpiece that is super easy and convenient. It makes using air abrasion chairside something you will want to do every day.

Use 50-micron aluminum oxide air abrasion to clean out the stain, etch the old composite, and etch the tooth. If any tooth structure is to be etched, this air abrasion is a replacement for phosphoric acid. So, in one easy step, you have prepped the tooth and the composite. A plus of this technique is that local anesthetic is not needed if the hole does not extend into the tooth.

Now you can go in and use your dentin adhesive and replace your repair composite. Today, dentin adhesives contain MDP or PMMA which is the chemistry we need for the new composite to bond to the old composite. If I were to repair a composite restoration with a handpiece and a burr, I would not get the same bonded interface between the new resin and the old resin.

For both ease, patient comfort, and the best bond, I choose to treat previously polymerized resin with air abrasion and then some sort of resin that contains either MDP or PMMA.

Related Course

E3: Restorative Integration of Form & Function

DATE: January 12 2025 @ 8:00 am - January 16 2025 @ 2:30 pm

Location: The Pankey Institute

CE HOURS: 41

Dentist Tuition: $ 7400

Single Occupancy with Ensuite Private Bath (per night): $ 345

THIS COURSE IS SOLD OUT Understanding that “form follows function” is critical for knowing how to blend what looks good with what predictably functions well. E3 is the phase of…

Learn More>

About Author

User Image
Lee Ann Brady DMD

Dr. Lee Ann Brady is passionate about dentistry, her family and making a difference. She is a general dentist and owns a practice in Glendale, AZ limited to restorative dentistry. Lee’s passion for dental education began as a CE junkie herself, pursuing lots of advanced continuing education focused on Restorative and Occlusion. In 2005, she became a full time resident faculty member for The Pankey Institute, and was promoted to Clinical Director in 2006. Lee joined Spear Education as Executive VP of Education in the fall of 2008 to teach and coordinate the educational curriculum. In June of 2011, she left Spear Education, founded leeannbrady.com and joined the dental practice she now owns as an associate. Today, she teaches at dental meetings and study clubs both nationally and internationally, continues to write for dental journals and her website, sits on the editorial board of the Journal of Cosmetic Dentistry, Inside Dentistry and DentalTown Magazines and is the Director of Education for The Pankey Institute.

FIND A PANKEY DENTIST OR TECHNICIAN

I AM A
I AM INTERESTED IN

VIEW COURSE CALENDAR