| Abstract [eng] |
1. Abstract Background/Aims: The aim of this study is to investigate and assess the different adhesive systems and their chemical and mechanical properties on the tooth surface in order to preserve as much tooth structure as possible. Adhesive techniques and their efficiency were analyzed. Objectives: 1. To evaluate the technical necessity of adhesive systems. 2. To evaluate the efficiency content of adhesive components. 3. To evaluate the influence of Self-Etch and Etch & Bond systems on long – term duration. 4. To evaluate the nature of the adhesive resin bond to dental materials. Research Methods: An Overview was implemented based on scientific articles including this topic. The databases used were Scientific & Medical ART Imagebase, CINHAL, Dentistry & Oral Sciences Source Alumni Edition using Pubmed and Elsevier. This Overview contains scientific data written in English language. Results: Lower results were found for self -etching adhesives than for Etch & Rinse adhesives. The marginal strength is significantly lower in the enamel of composite fillings after thermal and mechanical stress than for the Etch & Rinse systems. Dentin bond strengths varies according to the acid exposure treatment. With longer etching times, the risk of exposed collagen fibers in deeper layers increases, where it may not be completely penetrated by the components of the bonding system. The exposed collagen fibrils may consequently suffer hydrolytic degradation by matrix metalloproteinase. The pH value of self – etching adhesives determines the effectiveness of penetration and dissolution of the smear layer and thus the quality of the bond to the tooth structure. Conclusion: This Overview discusses the precise bonding techniques needed for long-term clinical effectiveness with different tooth shapes and dental materials. A modern adhesive system consists of a conditioner (acids, complexing agents), a primer (hydrophilic monomer in a solvent) and an adhesive (various monomers). After applying the total-etch technique, a primer-adhesive mixture is applied. The one-bottle systems are intended to make work easier, save time and reduce technique sensitivity. Mixing up different bottles or mixing ratios is impossible. However, these advantages are offset by more difficult moisture management. Water plays the central role here, as it is required on the one hand to set up the hydrophilic collagen fiber mesh of the demineralized dentin for penetration, but on the other hand it impairs bonding to the hydrophobic composite. Overdrying to reveal the etching pattern in the enamel requires "re-wetting". In contrast, Type I adhesives supply sufficient water to the dentin dried after phosphoric acid etching via the hydrophilic primer, whereas Type III and IV Self-Etch systems avoid this problem by simultaneous etching and priming. The solvents ethanol and acetone remove the excess water after infiltration of the adhesive into the dentin. However, in the context of wet bonding, these organic solvents must be prevented from drying out the dentin, as a collapse of the collagen mesh prevents the complete formation of the hybrid layer and leads to nanoleakage and postoperative hypersensitivity. In general, multi-bottle systems are sufficiently hydrated, but single-bottle Total-Etch or Self-Etch systems are not or not sufficiently hydrated for adequate infiltration. 2. Keywords: Adhesive systems, Etch&Rinse-system, Self-Etch system, Enamel, Dentin. |
