Winning the "Restorative Challenge" with the DUO-LINK™ SE System
Keep it Simple...Keep it Sealed!
Water is the clinician's worst enemy, and the use of adhesives and cements that are less than compatible could lead to the clinician's worst nightmare. A recent ADA Product Review stated that adhesive compatibility with the core material or the dual- or self-cure resin cement is the main concern, and that clinicians should be aware that sometimes manufacturers' recommendations for compatible core materials, adhesives, and cements do not quite match even within the same product lines.1
This is a bold statement and begs an answer to the question: "My crowns do not fall off, but are they silently leaking because of incompatibility with less than compatible adhesive systems- including resin cements with lower than expected conversion in self-cure modes?" State-of-the-art adhesive cementation systems are based on a tertiary component hierarchy: self-etch primers/adhesives with chemistries that are compatible with all self- and dual-cure resins; dual-cure resin cement polymerization mechanisms that maximally convert irrespective of the curing mode; and separate primers that covalently bond to either zirconia or lithium disilicate and porcelain internal surfaces.
"Keeping it sealed" in a fast and efficient manner is the restorative challenge, one that requires the clinician to create a water-resistant, hydrophobic, and resin-cement friendly surface on the dentin and enamel as well as the indirect restoration. The DUO-LINK SE System is a simple, universal, predictable means to accomplishing the goal of creating a hydrophobic seal with all indirect materials. DUO-LINK SE consists of ALL-BOND SE® for the tooth, Z-PRIME™ Plus and PORCELAIN PRIMER for the varying indirect substrates, and DUO-LINK™ Resin Cement which provides the flexural strength, fracture toughness, and degree of conversion required to complete a durable hydrophobic link between these two very different primed substrates (Figure 1 and Figure 2).
Bonding to Ceramics
Zirconia and lithium disilicates are considered the "next generation" of indirect esthetic restorative materials. CAD/CAM-processed copings and monolithic restoratives of zirconia and lithium disilicates offer high strength and fracture toughness with opacities and translucencies to allow for single or multiple restorations. With the creation of new innovative primers by BISCO, bonding to the substrates is the new clinical standard.
Adequate retentive designs of 6° to 12° with regular margins are inherently difficult to achieve in the "destroyed dentition." The classification of resin cements known as "self-adhesive resin cements," such as BisCem®, have simplified the bonding process where adequate retention/resistance form is accomplished and provides for adequate immediate retention. Primers used on the indirect substrates in conjunction with BisCem have been shown to significantly improve the bond and potentially reduce hydrolysis of self-adhesive cements to indirect substrates.
Less-than-retentive preparations and irregular preparation designs are the "status quo" in most clinical practices and are thus prone to water degradation when using these hydrophilic self-adhesive resin cements. The uses of hydrophobic resins are indicated in most of these non-retentive clinical situations.
"Keep it Simple...Keep it Sealed" was the mantra behind the creation of BISCO's DUO-LINK SE System. The creation of self-etching primer systems that are compatible and quick to use allow the clinician to incorporate much stronger, stable hydrophobic resin cements in as little time as previous weaker self-adhesive cements. The totality of the DUO-LINK SE System allows the clinician to standardize clinical protocols, which will lead to consistent optimal results and achieve the goal of creating the most hydrophobic seal possible.
The goal was to eliminate the guesswork clinicians currently have by creating an easy-to-use, "ultimate" indirect adhesive system. DUO-LINK SE is a simply displayed, comprehensive adhesive system that is efficient and predictable. It consists of ALL-BOND SE for dentin/enamel, Z-PRIME™ Plus for zirconia/alumina/metal; PORCELAIN PRIMER for lithium disilicate and other glass-based porcelains; and DUO-LINK dual-cure resin cement in an automix delivery, to complete the hydrophobic seal.
BISCO's DUO-LINK SE System
ALL-BOND SE is a highly acclaimed two-bottle self-etching adhesive offering stability, low film thickness, high bond/seal and is dual- and self-cure compatible. The compelling feature of ALL-BOND SE is its low film thickness and dual-cure compatibility, which are the two key components allowing for precise indirect marginal adaptation.
The use of primers to facilitate bonding to ceramics is well documented. Zirconia and lithium disilicates are two very different materials and require different primer formulations. Lithium disilicates/porcelains contain silica; therefore, durable bonds can be achieved through the combined application of hydrofluoric acid-etch and silane primers.2
Silane is ineffective on zirconia/alumina/metal oxides, which are crystalline in nature, do not contain glass, and, thus, cannot be etched.3 Z-PRIME™ Plus is the most predictable means to bond to zirconia. Creating primers that offer separate, specific chemistry to address the needs of these very different, individual indirect substrates has now been accomplished by BISCO.
DUO-LINK Dual-Cured Resin Cement is as consistent in its chemistry as it is in its ratings.
A testament to Dr. Byoung Suh's (BISCO's founder and president) catalyst-activated technology is DUO-LINK's time-tested, highly regarded conversion rate. Conversion rate correlates into impeccable flexural strength and fracture toughness necessary for contemporary indirect materials. Self-cure conversion is critical to the clinician, allowing for immediate clean-up and patient function (Table 1 and Figure 3).
DUO-LINK SE has a clinically advantageous working time of 2 minutes and a clinically effective intraoral setting time of 5.5 minutes. BISCO's chemistry is always compatible, never stored, always made fresh, and directly shipped to the clinician. Stability of the DUO-LINK Catalyst is the defining point of BISCO's DUO-LINK chemistry and is clinically shown by not requiring refrigeration. It is "catalyst-activated technology." DUO-LINK has been delivering for more than 10 years and counting. The creation of the DUO-LINK SE System is a synergistic display of adhesion excellence.
This article was written by Douglas Brown DDS, FAGD, senior manager of clinical affairs for BISCO, Inc.
References
1. ADA Professional Product Review [serial online]. Restorative Materials. Spring 2010;5(2):15.
2. Nagai T, Kawamoto Y, Kakehashi Y, et al. Adhesive bonding of a lithium disilicate ceramic material with resin-based luting agents. J Oral Rehabil. 2005;32(8): 598-605.
3. Cavalcanti N, Foxton RM, Watson TF, et al. Bond strength of resin cements to a zirconia ceramic with different surface treatments. Operative Dentistry. 2009; 34(3):280-287.
