How to place predictable, esthetic posterior restorations

Placing posterior composite restorations always has been a tedious procedure requiring precision and time. But in today’s economic climate, most clinicians must look for procedural efficiencies while still maintaining a high standard of care. The first challenge clinicians face, particularly with large Class II restorations, is assurance that the interproximal contact is adapted well to keep food and possible decay from reoccurring. The second is identifying a quick yet efficient means to restore the tooth. This would include sealing the interproximal box and placing a durable restoration. There are numerous composite restorative material choices on the market and Kerr is an organization with a long heritage of developing innovative resins and adhesives. Most recently, Kerr announced a new bulk fill restorative resin called SonicFill™.

What it does
SonicFill is a sonic-activated, single-step bulk fill composite system like no other. The system is comprised of a specially designed handpiece and a new composite material in unidose delivery. The resin is a highly filled proprietary resin with special modifiers that react to sonic energy. As sonic energy is applied through the handpiece, the modifiers cause the composite viscosity to drop up to 87%, increasing the flowability. This allows easy placement and precise adaptation to the cavity walls. Once the sonic energy is stopped the composite returns to a more firm non-slumping state that will allow the clinician to easily carve, contour and finish the restoration.

Because of SonicFill’s ultra-efficient curing characteristics, clinicians can place up to a 5 mm increment without the need for a final capping layer. This single step bulk fill material takes only a 20 second cure for the 5 mm placement.

Clinical case
A 56-year-old male was complaining about thermal sensitivity on tooth No. 20 (Fig. 1). Upon examination there was a large disto-occlusal amalgam with recurrent decay around the occlusal margin. This case is very common yet it introduces the following repair challenges and concerns for the dentist: obtaining interproximal contact, avoiding excessive volumetric shrinkage and sensitivity because of the size of the cavity, and determining if the material has the physical properties to clinically perform long term.Even though there are numerous options, one more factor that is seldom mentioned is the amount of time a restoration of this size will take to complete. The concerns about shrinkage, time and strength of a composite restoration can easily be answered with SonicFill.

The amalgam was removed and a rubber dam was placed to ensure isolation of the prepared tooth during the adhesive process as well as placing the composite  (Fig. 2). I cleaned the preparation with a 2% chlorhexidine for 15 seconds and then rinsed. This is to ensure the tooth is clean before the adhesive process.

There are many adhesive techniques for the clinician to choose from to prepare the tooth for the composite restoration. These include total-etch and self-etch adhesives. I chose Optibond XTR self-etching light-cured universal adhesive. This adhesive allows maximum bond strength to dentin and even uncut enamel without phosphoric acid. The Optibond XTR primer is first placed over the entire preparation for 20 seconds and then evaporated. Then the adhesive is placed over the enamel and dentin for 15 seconds and the solvent is evaporated and light cured for 10 seconds (Fig. 3).

What makes it different
SonicFill’s uniqueness resides in the composite material that is dispensed using a sonic handpiece. The proprietary rheological modifiers in the composite react to the sonic energy from the handpiece reducing the viscosity almost 90%. This allows the composite to adapt in the most difficult to reach areas of the prepared tooth when it is in its lowest viscosity (Fig. 4). Once the preparation is filled up to 5 mm and the sonic energy is stopped, the composite returns to a non-slumping state that allows the clinician to easily carve and contour the composite. Once the appropriate contours are obtained a 20 second cure is all that is needed to properly cure up to a depth of 5 mm. Because SonicFill is so highly filled (83.5%) there is very little shrinkage with good polishability (Fig. 5).

The advantage
With increasing time constraints on the clinician, SonicFill offers a consistent, predictable solution for quality posterior restorations. When a patient has a deep Class I or Class II posterior restoration the dentist can place a rapid flow of composite into the cavity preparation quickly and effortlessly knowing SonicFill will have superior adaptation. With SonicFill, the dentist can restore a tooth from start to finish in less than 3 minutes in most cases. Saving chair time for the clinician and the patient with a strong adaptable esthetic restoration is a win-win for both the dentist and patient.