How to: Bridge the generation gap

Until recently, all “Sixth Generation” self-etching/priming adhesives contained volatile solvents that must be evaporated prior to light curing to provide consistent bond strengths. Now a solvent-free self-etching, single-bottled system has been introduced by Pentron Clinical Technologies. Bond-1 SF Adhesive uses a proprietary formulation said to eliminate the need for commonly used solvents such as acetone, alcohol and water. This not only reduces the number of steps in application, but removes the ambiguity of air-volatilizing residual solvents prior to light curing.

Because residual solvents can reduce bond strengths and disrupt the hermetic seal needed to eliminate water transportation from the underlying dentin, the potential for “water-treeing” effected by osmosis is reduced. This breakthrough in technology renders an adhesive system that defies the typical label of the self-etching primer/adhesive “generation.”

In-vitro clinical studies indicate that bond strengths exhibited by Bond-1 SF Adhesive are as high as results obtained when using traditional total-etch and self-etch adhesives, and restoration microleakage is comparable or superior when compared to four other bonding agents.^1,2

By eliminating solvents from the formulation, evaporation during storage and before application is prevented. The resulting longer working times provide a greater margin for error compared to similar products. The material is self-leveling and requires only one coat with no air-thinning prior to light curing. Bond-1 SF Adhesive is indicated for use on direct composite restorations, and can be used with dual cure materials when the initial layer of the dual-cure composite is light cured.

Case presentation

A patient presents with the desire to remove an unsightly amalgam restoration on tooth No.19 (Fig. 1).

01. After anesthetization, rubber dam isolation is achieved, and the amalgam is removed (Fig. 2).

02. For this case, the syringe delivery system of Bond-1 SF Adhesive is used. The screw cap is removed and the provided flocked tip is twisted onto the syringe. Because Bond-1 SF Adhesive is a self-etching system, no phosphoric acid conditioning is necessary.

03. Slight pressure is exerted on the plunger of the syringe to begin the flow of material through the flocked needle. The material is applied to dentin (Fig. 3) and the enamel cavosurface with a scrubbing motion for 20 seconds. The handling properties permit a smooth, even coat of material across the interface with a low film thickness. There is no need for air-thinning or volatilization of any solvents (Fig. 4).

04. Using Pentron’s Avante halogen light, Bond-1 SF Adhesive is light cured for 10 seconds (Fig. 5). Fig. 6 shows the cured layer of adhesive.

05. A dentin body shade of composite (Pentron’s Artiste Shade A2 Dentin Body) is applied and filled to the dentinoenamel junction in 2 mm increments without connecting opposing lateral walls to manage polymerization stress on the bond (Fig. 7).

06. This layer is sculpted to replicate the cuspal slopes of the cavosurface and light cured for 20 seconds (Fig. 8).

07. A final layer of enamel composite (Pentron’s Artiste Shade A Enamel) is applied and blended to the margins of the restoration with a ball burnisher to assure full adaptation into the primary and secondary grooves (Fig. 9). This layer is sculpted to match the existing cavosurface anatomy and light cured for 20 seconds (Fig. 10).

08. The rubber dam is removed and the occlusion is adjusted. The final result is shown in Fig. 11.

Closing thought

As the technique and chemical formulations have advanced for the last 60 years, the classification of dental adhesives have been commonly segregated into “generations.” The latest, so called “Sixth Generation” materials, are well accepted for their easy use and reduction in post-operative sensitivity. Until the release of Bond-1 SF Adhesive, other materials in this class have contained solvents that must be completely evaporated before light curing. Bond-1 SF Adhesive bridges the “generation gap” by offering a formulation that defies categorization as any “generation,” dramatically reducing chair time and the chance for post-operative sensitivity.

About the author

Dr. Blank maintains a private practice in Fort Mill, S.C. He is an adjunct instructor in the Dept. of General Dentistry at Medical University of South Carolina, College of Dental Medicine.