# A Literature Review of Adhesive Systems in Density: Key Components and Their Clinical Applications
## 6 Resin Adhesive Systems
### Self-Etch Adhesive Strategy
For instance, some of these products are: One Coat 7.0 (Coltene, Altsattaten, Switzerland), Xeno IV (Dentsply Sirona, York, PA, USA), G-BOND (GC Corporation, Tokyo, Japan), OptiBond All-In-One (Kerr Corporation, Orange, CA, USA), Clearfil S3 Bond Plus (Kuraray Co., Ltd., Tokyo, Japan), Adper Easy One (3M ESPE Dental Products, St. Paul, MN, USA), Clearfill DC Bond (Kuraray Co., Ltd., Tokyo, Japan), Xeno DC IV (Dentsply Sirona, York, PA, USA), and Futurabond DC (VOCO GmbH, Cuxhaven, Germany) [9]. The SE I and ER II adhesives are simpler versions of the ER III and SE II adhesives [9; 33]. It should be emphasized that simplified adhesives are user-friendly and have gained popularity as clinicians prefer easier-to-use dental materials [9; 33]. Despite its ease of use and reduced technique sensitivity, the simplified adhesive approach has led to a decrease in effectiveness and durability [15]. Because of their hydrophilicity and the absence of  
Figure 18: Illustrative steps of the in vivo analysis of the permeability of adhesives [283; 284]. A cavity was prepared and bonded (**a**), and an impression of the cavity floor was obtained (**b**). After pouring a cast with epoxy resin, specimens analyzed under a scanning electron microscope revealed water droplets emanating from the adhesive surface (**c**). These droplets are the morphological evidence of water that seeped from the adhesive layer during the setting time of the hydrophobic impression material, forming major droplets as well as minor droplets (pointing finger) over the adhesive [267]. hydrophobic bonding resin coating, cured adhesive films can act as permeable membranes, enabling water to move across the adhesive layer [9]. Based on the existing literature, dental adhesives with a hydrophobic bonding resin as the last stage of the clinical procedure, such as ER III adhesives and SE II adhesives, are more stable and provide longer-lasting restorations compared to their simplified equivalents [15; 33]. Certain suppliers provide hydrophobic liners paired with the SE I adhesive (All-Bond SE/All-Bond SE liner (Bisco, Schaumburg, IL, USA)) [15]. Furthermore, simplified adhesives are not compatible with dual or chemically activated resin composites. Once chemical-cure and dual-cure resin composites are combined with simplified adhesives, leftover uncured acidic monomers from the cured adhesives' oxygen-inhibited layer (not covered by a hydrophobic bonding resin) come into direct contact with the composite material [285]. The acid deactivates the aromatic tertiary amines in the dual-cure or self-cure compound, preventing their polymerization [286; 287; 288]. This could become more troublesome if clinicians employ composites and adhesives from various suppliers. Some simplified adhesives are specifically designed to be used in conjunction with their patented dual-cure or self-cure composites, with the adhesive requiring independent photopolymerization (for example, Clearfil S3 Bond Plus/Clearfil DC Core Plus (Kuraray Co., Ltd., Tokyo, Japan)). Other SE bonding systems address the issue of incompatibility with self-cured or dual-cured composites by mixing the adhesive with a dual-cure or self-cure activator (for example, AdheSE/AdheSE DC (Ivoclar Vivadent, Schaan, Liechtenstein)) [15]. SE adhesives, including SE II and SE I, offer several advantages [9; 15; 33]. Mild SE adhesives achieve shallow hybridization of around 1 \(\upmu\)m, allowing for easy resin diffusion in a short clinical period. This results in a high-quality HL rather than focusing on its thickness. The dental substrate is only moderately demineralized, permitting micro-mechanical interlocking. Limited collagen exposure makes it more resistant to enzymatic destruction. SE adhesives, especially SE II, have a proven track record, with products like CSE (Kuraray Noritake Dental, Tokyo, Japan) being reliable for over 20 years. Functional monomers like 10-MDP enhance chemical interactions and long-term bonding.