Bisco’s DUO-LINK™ Composite Luting Cement

Bisco’s DUO-LINK composite luting cement is a dual-cured, highly filled cement and competes in a very crowded and often confusing product niche in restorative dentistry. DUO-LINK is not a newly introduced product, but one that has had a long history of producing excellent clinical results.

So why is this product of such great interest today? Selecting the ideal cement from the pure resin, self-adhesive resin, glass ionomer categories with all-ceramic, metal ceramic and post cementation procedures is a challenge and most clinicians use multiple materials in their day-to-day treatment. DUO-LINK shines as a versatile cement for numerous clinical indications when the doctor demands a dual-cured chemistry for the clinical procedure. It is suited for adhesive cementation of metal supported porcelain-fused-to-metal crowns and bridges, crowns, inlays and onlays fabricated from metal, composite resin or ceramics, and metal and fiber-reinforced endodontic posts.

In looking at what makes DUO-LINK stand out as a luting material, it is important to understand that many cements do not cure equally as well in the purely light-cured mode compared to the self-cured mode. For many clinical situations it is not possible to get light penetration through the restoration to the deepest part of the cement layer. The integrity of the cement (and the restoration itself) then is dependent on the chemical curing components to achieve a high degree of conversion (cure) without light exposure. DUO-LINK achieves a very high degree of conversion in both the self- and light-cure modes, independent of each other. The physical properties of DUO-LINK also are excellent and balance a high filler content for marginal wear resistance with a low film thickness and flow to ensure ease of cementation.

Catapult evaluators listed the two most important characteristics of a luting material as the ease of removing excess cement and the durability of the cement margin. These characteristics were closely followed by the working time and the intrinsic physical properties of the cement.

Findings from the Catapult Evaluation
95% of the Catapult evaluators would use Bisco DUO-LINK cement for at least some clinical indications in their practices. In situations where adhesive cementation is required, such as with single all-ceramic restorations made from a feldspathic or leucite ceramic (i.e. Empress I) or when there is a compromised retention form, this material (in conjunction with a compatible adhesive system) would be a material of choice.
81% of the evaluators rated the flow characteristics of the cement as “just right” with less than 5% feeling the working time was too short. This characteristic is critical to ensure full and complete seating of the restoration to achieve the best marginal adaptation. The film thickness of the cement was rated either very good or excellent by more than 75% of the evaluators.

The majority of evaluators rated the automix delivery system as close to ideal in terms of extrusion force and the quantity of material in the delivery system. The delivery system was especially noted for creating a minimal amount of wasted material. 62% of the evaluators found the cement working time to be “just right” with fewer than 5% who felt the working time was too short. Favoring a slightly longer working time is better in most clinical situations to eliminate the chance for incompletely seating a restoration.

Clean-up of the excess cement also was rated very highly by the Catapult evaluators. On a 1-7 scale where 1 represented ‘easy’ and 7 ‘very difficult,’ clean-up in the self-cure mode was rated 2.8 and in the light- cure mode 2.9-both excellent scores. As with all resin based cements, the timing of cement removal in the light-cured mode is dependent on the power of the light used. A bench trial of the cement and the light to be used clinically can help the clinician gauge the appropriate clean-up timing.

DUO-LINK is available in a translucent shade and as such would not provide significant color modification to the final restoration. While certainly this cement can be used for cementing veneers, for achieving significant color stability a light-cure only cement such as CHOICE 2 would be preferred.

The very high percentage (95%) of evaluators that would incorporate this cement into their practices is impressive and reflects the very good physical properties and the well accepted handling characteristics of this cement. While certainly it would not be the definitive choice for cementing all indirect restorations, it represents a terrific option when an adhesive cementation technique is indicated.

Key tips to this product
DUO-LINK is designed for use with universal adhesive systems such as ALL-BOND 2, ALL-BOND 3, ONE-STEP PLUS or ALL-BOND SE. Some incompatibilities may occur with dual-cured resin cement systems and some adheesive systems, especially adhesives that are low in pH, such as most self-etching systems. Prior to using DUO-LINK with other adhesives, check with the manufacturer to be sure there are not unexpected interactions that could inhibit chemical curing of the cement.

At room temperature the working time for DUO-LINK is 2 minutes and the setting time is 5 minutes 30 seconds for dual-syringe mixed material. Both working and setting times will be accelerated by mouth temperature, and by coming into contact with some adhesive system primers, depending on the adhesive system used. When used for the first time, careful attention to the intraoral setting behavior is important to prevent the cement from setting to a point that makes removal of the excess difficult.

Promotion of adhesion of DUO-LINK to the restoration surface can be accomplished by the appropriate preparation of the metal, ceramic or composite surface and the use of a suitable bonding primer for the specific material being cemented.

This review represents a summary of the findings amongst the Catapult evaluators, who used this product to cement a wide variety of restorations. While a small minority would have preferred the cement to have a slightly shorter work/set time, the survey results show that overall there was wide acceptance of this cement, especially for adhesive cementation of ceramic restorations.