This mechanically altered surface is relatively homogeneous with occluded dentinal tubular openings. Achieving a biocompatible bond to moist dentin while preventing bacterial invasion is critical.
Seven and possibly eight distinct generations of dentin bonding agents have evolved. The first generation was developed in the late 1950s and early 1960s and was composed of polyurethanes, cyanoacrylates, glycerophosphoric acid dimethacrylate, and NPG-GMA (N-phenyl glycine and glycidalmethacrylate). All these materials were disappointing clinical failures. In vitro shear bond strengths were only approximately 10 to 20 kg/cm2. Nearly two decades later, second-generation dentin bonding materials were introduced (Scotchbond, Dentin Bonding Agent, Creation Bonding Agent, Dentin-Adhesit, Bondlite, and Prisma Universal Bond). Most were halophosphorus esters of bis-GMA that were designed to adhere to the mineral portion of the dentin as a phosphate-calcium bond. In vitro bond strengths of these materials were reported to be 30 to 90 kg/cm.2, 3 The bond, however, was hydrolyzed over time in the oral environment, which contributed to their poor clinical success.3–7
The third-generation dentin bonding agents flooded the market in the early 1980s. Bowen et al.4 introduced a novel oxalate dentin bonding system in 1982. Originally this system was cumbersome and unpredictable, but it demonstrated a marked improvement, with bond strengths of 100 to 150 kg/cm2. The acidified ferric oxalate in this system was believed to be a source of marginal discoloration, and the complicated series of reagents made the system clinically cumbersome. Bond strengths improved, with modifications close to that of composite resin bonded to etched enamel at 200 to 220 kg/cm2. Nevertheless, clinical success was not satisfactory.
Clinical procedures were simplified by the simultaneous etching of the enamel surface and conditioning of the dentin. This “total etch technique” improved the bond strength to dentin as well.7
Fifth-generation bonding agents are essentially a modification of the fourth generation materials. They are self-priming “one-bottle” systems allowing faster and easier clinical application.8 The self-etching bonding systems demonstrate some chemical bonding but they do not show enough improvement to surpass those of the bond created when etch-and-rinse systems with phosphoric acid etched enamel are used.9
In the late 1990s, sixth-generation “self-etching” primers were introduced. These bonding adhesives incorporated an acidic primer that eliminated a separate acid-etching step.10 Some systems require mixing the primer with an adhesive before placement, whereas others require a separate adhesive to be placed over previously applied primer. Although they reduced the incidence of posttreatment sensitivity11 their bond strengths are lower than those of previous fourth- and fifth-generations systems.12
Introduced in late 2002, seventh-generation “all-in-one” systems combine materials for etching, priming, and bonding in a single solution. Studies show that these agents exhibit bond strengths and margin sealing equal to sixth-generation systems.13 All-in-one bonding solutions are available in bottles and unit doses.
In 2010, VOCO America introduced VOCO, Futurabond DC, a nano-reinforced, self-cured, light-cured, and dual-cured one-step, self-etch adhesive in a single-dose delivery system that they have designated as an eighth generation system.14 With a manufacturer’s reported adhesive strength of more than 30 MPa to both dentin and enamel when used with light-cured composite resins, Futurabond DC exhibits bond strengths similar to those of fourth- and fifth-generation adhesives.15
Ideal characteristics of a dentin bonding agent
The ideal dentin bonding agent should achieve the following:
Despite dramatic improvements in dentin bonding agents, clinical techniques are still confusing, even though research and product information on the subject have dramatically increased. An electronic Medline search using the phrase “dentin adhesive” as of July 2012, lists more than 50 publication abstracts. A Google web search using the keywords “dentin” and “adhesive” produced more than 24,900 scholarly works and 322,000 web search results with up-to-date research, discussion groups, and promotional information.16
Sufficient laboratory and animal data to predict clinical performance of dentin bonding agents are currently lacking. In addition, no large-scale controlled clinical trials comparing the performance of these materials in humans have been done. The most important long-term data include only 100 restorations, but demonstrated a 93% success rate for the three-step bonding approach over a 12-year period.16 This study implies the validity of the three-step approach. Fortunately, however, some progress has been made in attempting to support scientifically the clinical choice between bonding agents. The American Dental Association (ADA) Acceptance Program was extended for professional products that included “Dentin and Enamel Adhesive Materials;” however, this Acceptance Program was discontinued in 2007. The ADA Standards Committee on Dental Products (SCDP) develops standards for dental materials, but standards are still pending for dentin bonding agents. However, the Acceptance Program with guidelines for materials that treat hypersensitivity is still current, and two dentin bonding materials are listed by the ADA (Table 3-1). Even though the Acceptance Program for dentin and enamel adhesive materials was eliminated, the ADA lists current products in the dentin bonding category, as shown in Table 3-2.
|Microprime B||Danville Materials Inc||Microprime B with benzethonium chloride and HEMA, is a formulation that will not burn soft tissues. Reliably eliminate postoperative sensitivity with superior antimicrobial qualities. Use with all total-etch, cements, amalgam and on cervical erosions.|
|G5 All Purpose Desensitizer||Clinician’s Choice Dental Products Inc||G5 helps solve the problem of postoperative sensitivity in a single step. G5 contains 5% glutaraldehyde and 35% HEMA to decrease in sensitivity without affecting bond strength and help prevent bacterial growth in tooth/restoration interface.||None|
Data from ADA Dental Product Guide. www.ada.org/productguide/c/19/Bonding-Agents. Accessed October 2013.
|ACE ALL-BOND SE||BISCO Dental Products||ACE ALL-BOND SE is a self-etching bonding agent that combines etching, priming, and bonding in a dual-chamber cartridge dispensing system.|
|ACE ALL-BOND TE||BISCO Dental Products||ACE ALL-BOND TE is a single drop universal dental adhesive dispensing system that lets you prime and bond in one application. ALL-BOND TE is based on proven ALL-BOND 3 technology. It is an ethanol-based, dual-cured, total-etch adhesive system that combines outstanding performance, versatility, and durability for all dental applications.|
|Adper Easy Bond Self-Etch Adhesive||3M ESPE||Adper Easy Bond Self-Etch Adhesive is a one-bottle, one-coat solution. For those who prefer using a total etch adhesive, a new “selective etch” technique allows dental professionals to etch cut and uncut enamel surfaces.|
|Adper Single Bond Plus Adhesive||3M ESPE||Adper Single Bond Plus Adhesive incorporates a nanofiller technology that contributes to high dentin bond strength performance. The nanoparticles will not clump or settle, so no shaking is required before use. The adhesive is available in a convenient, transparent bottle or an easy-to-use unit-dose delivery system.|
|ALL-BOND 2||BISCO Dental Products||ALL-BOND 2, the original three-step adhesive, is still unsurpassed in its comprehensive ability to bond to a multitude of substrates. ALL-BOND 2 has a dual-cured primer for higher conversion rates, and contains BISCO’s own patented hydrophilic monomer (BPDM).|
|ALL-BOND 3||BISCO Dental Products||ALL-BOND 3 micro-mechanically bonds to all substrates, is used for all bonding procedures and is compatible with light-, dual-, and self-cured materials. The ALL-BOND 3 system offers increased hydrophobicity for a long-lasting adhesive bond. The HEMA-free, radiopaque ALL-BOND 3 resin reduces the chance of misdiagnosing caries.|
|ALL-BOND UNIVERSAL||BISCO Dental Products||BISCO’s ALL-BOND UNIVERSAL is a single-bottle bonding agent that combines self- and total-etch bonding, plus the resin layer and an activator into one universal bottle. As a universal adhesive, it is designed to work with light-, dual-, and self-cured composite resin and cement materials for all direct and indirect procedures.|
|BeautiBond||Shofu Dental Corporation||New seventh-generation bonding agent has an exclusive chemistry with unique dual adhesive monomers that deliver equal bond strength to enamel and dentin.|
|Bond-1 SF Solvent Free SE Adhesive||Pentron Clinical||Bond-1 SF Solvent-Free SE Adhesive is a light-cure, one-coat, self-etch adhesive that is truly in a league of its own! Bond-1 SF forms an interactive bond between the minerals of the tooth structure and the resins of the bonding agent, without the use of acetone, water, or alcohol, providing a superior bond to both dentin and enamel.|
|Clearfil SE Bond||Kuraray America, Inc.||Kuraray, after inventing the self-etching technique with CLEARFIL LINER BOND 2 in 1993, has surpassed their universally accepted total-etch technology with a new product—a new-generation self-etching primer and bonding system called CLEARFIL SE BOND. CLEARFIL SE BOND is a simplified, light-cure bonding system containing a water-based primer.|
|Clearfil SE Protect||Kuraray America, Inc.||CLEARFIL SE PROTECT provides the same defining properties that have made CLEARFIL SE BOND the market leader plus two other clinically significant technologies—fluoride release and newly developed MDPB monomer.|
|Futurabond DC||VOCO America, Inc.||Self-etch dual-cured bonding agent for all light-, dual-, and self-cured resin materials. Futurabond DC is unique in that it is reinforced with nano-particles, which increases the bond values and marginal integrity. It is moisture tolerant, needs no refrigeration, and gets more than 30 MPa to dentin and enamel with light-cured composite resins.|
|G-ænial Bond||GC America, Inc.||G-ænial Bond is a one-step, self-etch, seventh-generation bonding agent. Its improved design, HEMA-free formulation, improved bond strengths and easy application make it the bonding agent of choice. Designed specifically for “selective etching” technique to give the professional the maximum advantages.|
|G-BOND||GC America, Inc.||G-BOND is a revolutionary seventh-generation (single component) adhesive that takes the guesswork out of bonding. The unique combination of phosphoric acid ester monomer and 4-MET adhesive technology creates superior etch and adhesion to enamel in addition to providing chemical and mechanical seal to dentin—referred to as the Nano Interaction Zone.|
|ONE-STEP||BISCO Dental Products||ONE-STEP is a light-cured, single component adhesive that, unlike others, bonds to a multitude of dental substrates, including self- and dual-cured materials. Its proprietary chemistry makes it an exceptional adhesive for metal bonding, including implant abutments|
|Oxford Bond SE||Oxford Scientific Dental|