Bulk-Fill Work in Dental Composite

Dental composites have been successfully in use for several years now, and one of the on-going debates is whether the bulk-fill technique works or not. C-Shape is the new instrument system that is giving a new perspective to this conversation. C-Shape is the perfect composite instrument that leads to less tooth sensitivity, more patient comfort, and a higher level of cosmetic dentistry while keeping costs low. These results are largely based on the instrument’s ability to tightly pack composite into the cavity and seal the margins better.

Relying on Traditional Techniques for Successful Fillings

The idea is to follow the traditional, basic principles of r estorative dentistry that used to govern amalgam fillings and other restorations made of metal alloys. The focus is on the condensability of the material and the ability to burnish the filling. With this technique, we can improve the patient experience and improve the quality of fillings that we are providing for our patients.

Before, it wasn’t possible for us to incorporate this technique, as composite and its relationship with the instrument would not really allow it. However, with the C-Shape instrument, that goal is more attainable, and the results are once again proving that if we can follow those principles a little closer, we will have more success. This system is also making it significantly easier for the operator to perform the work.

Understanding Traditional Metal and Alloy Dental Materials

Let’s review the basic principles that can be applied to metals and alloys, and not to resin-based materials.

The first factor to consider is condensation of filling material. With metal and alloy fillings, dentists were able to really pack the material into the cavity, which made the actual restoration stronger in its body. This increases the compressive strength of the material. The difference comes in two forms:

  • The body of the filling is stronger because the same space is now filled with a higher volume of the same material, and the molecules are more tightly packed into it. This has many advantages, but for the topic at hand, the strength of the body of the material is increased.

  • Voids in the body of the material are not there or are greatly minimized.

  • Voids between the material and the bonded prepped wall of the cavity are also avoided.

If sensitivity can be overcome with bulk-fill, the advantages are obvious: time saved and congruence of the material body. The sensitivity is related to dimensional stability—and that is the factor that C-Shape minimizes the effect of.

The tightly-packed molecules are less likely to shrink, and at a lower percentage, than loosely packed molecules. This is the first factor that we are going back to with this system. If we can pack our materials at a physical level more tightly, then the material is more stable.

The second principal is marginal adaptability. With the traditional materials, we were able to simply burnish the margins where we could instrument, and if placed in a self-cleansing or easily-to-clean areas, those areas could be possibly burnished there after a band was removed.

With the composite filling, if the composite can be really pushed in with pressure into a cavity (class I, II, or III), and you get some level of extrusion of excess material (which should be kept at a minimum), then we can reasonably expect that the cavity walls were tightly adept with the material and the margins as well. A micro-mechanical retention forming at that time should have a greater surface area to bond to and be a less-strained bond under curing and be more intimate.

On the occlusal or workable margins, the gliding and burnishing motion which can be employed lets there be a fine, perfectly formed contact between the composite and the enamel surface that does not require much finishing after cure, and the junction can remain without trauma by hand instrument or handpiece work.

"Composites are easier to place since there is no pull back"

- Dr. G. Felen

"Works very well! It makes resins much more efficient to complete"

- K. Ducote (dental student)

"I can't believe how much I love the instrument. I'm ready to order more!"

- I. Renieris

"I have added it to my composite placement instruments."

- C. Kerbaugh