Influence of oxygen‐inhibited layer on dentin bond strength of chemical‐cured resin composite

Abstract

This study evaluated the influence of an oxygen-inhibited layer on the surface free energies of three single-step self-etch adhesives and on the bond strength of chemical-cured resin. Adhesives were applied to bovine dentin and light irradiated, and the oxygen-inhibited layer was either retained or removed. Surface free energies were determined by measuring the contact angles of test liquids placed on the cured adhesives. Dentin bond strengths of chemical-cured resin with and without the oxygen-inhibited layer were measured. Ultrastructural observation of the restorative-dentin interface was made by scanning electron microscopy. For all surfaces, values of the estimated surface tension component, Lifshitz-Van der Waals force (γS(LW)), were relatively constant. Values for the Lewis acid (γS(+)) component increased slightly when the oxygen-inhibited layer was removed, whereas those of the Lewis base (γS(-)) component decreased significantly. The bond strength of the chemical-cured resin composite was significantly higher in specimens without an oxygen-inhibited layer (7.6-8.0 MPa) than in those with an oxygen-inhibited layer (4.8-5.2 MPa). Small gaps between adhesive and resin composite were found for the group with an oxygen-inhibited layer. These results indicate that the absence of an oxygen-inhibited layer in single-step self-etch adhesives promotes higher dentin bond strength of the chemical-cured resin.

Important compositional characteristics in the clinical use of adhesive systems

“…However, the long-term durability of the resin-dentin interdiffusion zone may be compromised by the presence of some ingredients of adhesives. Challenges for future research include refining the dentin-resin interface to improve adaptation and enhance long-term resistance to hydrolysis (87)(88)(89)(90).…”

Cross‐infection control in clinical training: Development of a device for storing a composite resin in restorative dentistry

“…Although the dappen dish is an option commonly used in developing countries because it allows the control of cross‐infection (Bambace et al, ), its use might interfere with the surface characteristics of the restorative material used (Suh, ), as observed in this study. Conditioning resin in a dappen dish permits contact with ambient oxygen, promoting a chemical reaction and compromising the resin's properties (Yamaji et al, ). Suh () stated that the surface layer of composite resin that comes into contact with air forms a sticky oxygen‐inhibited layer.…”

“…In addition, to date no studies have tested the physical and mechanical properties of this resin. The placement of the necessary portions of composite resin into dappen dishes is an alternative often adopted by students, but is not recommended due to the exposure of the material to light, and other environmental influences (Yamaji, et al, ).…”

Functional dendritic compounds: potential prospective candidates for dental restorative materials and in situ re-mineralization of human tooth enamel

“…This problem originated from the conversion of intermolecular van der Waals distances of the resin monomers to the covalent bond lengths during photopolymerization. [43][44][45][46][47] Thus, many research efforts have been focused to reduce polymerization shrinkage of resin-based dental composites. In this respect, the use of monomers can be polymerized by ring-opening polymerization (e.g., siloranes), [48][49][50] incorporation of bulky cross-linking agents such as (polyhedral oligomeric silsesquioxanes (POSS)), [51][52][53] and thiol-ene or methacrylate-thiol-ene systems 15,[54][55][56] could be reduce the polymerization shrinkage and the associated stress.…”