Great Chemistry: The Key to Posterior Restoration Success With Kerr’s SonicFill™
Dentists who find performing posterior restorations challenging may very well appreciate the science behind a unique solution that makes the process faster, more predictable, and more profitable. Kerr National Field Trainer Tony Bilotto is well versed in how Kerr was able to overcome “the volumetric shrinkage effect” that occurs with composites—which are made of glue-like resin and glass particle filler. “Composites shrink away from the sides of the tooth when the resin hardens; it pulls the tooth cusps in and potentially causes fractures on the outside of the tooth,” he explains.
Efforts to reduce this shrinkage effect have included: the 2-mm layering method, bulk-fill flowable composites, and the addition of more glass to the restorative—all of which have issues of their own, Bilotto insists. “Adding more glass made the material too firm to adapt well to the proximal box, and layering the less viscous higher-resin materials was not only time consuming, it also increased potential for phase separation between layers, which can cause voids where bacteria can hide and cause further damage to the tooth. Even bulk-fill flowables still need a capping layer, so phase separation is still a challenge.”
Kerr, he says, took a scientific approach to solving this dilemma. “In the past, the only way to achieve the flowability that enables the restorative to fill in the point angles of the proximal box was with a higher-resin–based composite for which the challenge was high volumetric shrinkage. But SonicFill™ is able to offer the best of both—flowability and low shrinkage—by maximizing the amount of glass (84%) and minimizing resin (16%); so, when curing, there’s much less resin to shrink and pull.”
This, Bilotto says, was achieved by adding a rheological modifier to the chemistry that enables the highly filled, firm composite to temporarily change viscosity—via a proprietary handpiece included in the product kit that delivers a sonic vibration—and with this comes the ability to handle like a flowable composite momentarily. “When the energy is removed, the viscosity becomes more wax-like and then extremely hard like tooth structure when cured.”
What this means for dentists, he notes, is that they can use SonicFill 2 to fill a posterior cavity with a single 5-mm layer, with no liner or capping layer, and still achieve a fully cured material. This material is, thus, able to transform a tedious, repetitive procedure into one that is faster and more reliable, Bilotto asserts. “Doing a full quadrant at once, the doctor could save a half-hour of chairtime.”
As for light curing, Bilotto says there are many excellent curing lights available on the market, but points out special features in the Kerr Demi™ Ultra in particular that enable it to maximize power while keeping the tooth cooler than other lights, thus avoiding complications such as pulpitis. “The beams of light are more like columns, which enable the light to penetrate deeper into the composite,” he says, adding that heat is also minimized by what the company calls “periodic level shifting” and by placement of the LED into the tip. Minimizing the heat output is important clinically to avoid any irreversible damage or sensitivity. Further, he says, the Demi Ultra is able to store energy using not a battery, but an ultracapacitor. “Recharging—which would take 3 hours with a battery—takes only 30 seconds and is sufficient for about 40 cures.”
Bilotto concludes that although both SonicFill and the Demi curing light can be easily mastered using provided instructions and materials (SonicFill comes with a DVD showing procedures), he stresses that Kerr is committed to education that goes far beyond mastery of its products. “Kerr Professional Education, which was launched this year, focuses on education to doctors in multiple settings. There are hundreds of courses for which doctors can sign up and get CE credits,” he says.
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