Electric device improves bonds of simplified etch-and-rinse adhesives

Abstract

d e n t a l m a t e r i a l s 2 3 ( 2 0 0 7 ) 513-518 a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . i n t l . e l s e v i e r h e a l t h . c o m / j o u r n a l s / d e m a Objectives. This study investigated the effects of an electric field produced by a new device for the application of etch-and-rinse adhesives on demineralized dentin surfaces. Electric device improves bonds of simplified etch-and-rinse adhesives Methods. Three simplified etch-and-rinse adhesives (Single Bond, Prime&Bond NT and One-Step) were applied with the electric device and compared with controls prepared with disposable sponges. Specimens were processed for microtensile bond strength test and nanoleakage investigation using high resolution SEM.Results. Microtensile testing revealed higher bond strengths (p < 0.05) for all adhesives tested when electricity was used. Adhesive interfaces prepared with electric impulses exhibited very homogenous hybrid layers with minimal nanoleakage compared with the controls.Significance. The use of electricity produced by a new electronic device during the application of dentin adhesives may increase adhesive adaptation to the dentin substrate and improve dentin hybridization due to the substrate modifications induced by an electric field on the demineralized dentin organic matrix. IntroductionDespite the recent developments in adhesive dentistry to reduce the number of working steps and to simplify the clinical procedure, the new simplified adhesives do not produce better results in in vitro tests [1] or improve clinical efficacy [2]. Ironically, the most user-friendly simplified adhesives, the socalled self-etching one-step adhesives, exhibited the lowest bond strengths and the least predictable clinical performances over time when compared with the multi-step etch-and-rinse and self-etch systems [2,3]. Previous reports have shown that one of the major disadvantages of the etch-and-rinse systems is incomplete infiltra- * Corresponding author at: UCO of Dental Sciences, University of Trieste, Via Stuparich, 1, I-34129 Trieste, Italy. Tel.: +39 040 3992192; fax: +39 040 912579.E-mail address: lbreschi@units.it (L. Breschi).tion of the exposed dentin matrix due to the collapse of the collagen fibrils after removal of the mineral phase [4][5][6]. A layer of disrupted collagen fibrils may interfere with adhesive penetration and the formation of the hybrid layer. Incompletely infiltrated voids within these hybrid layers may be revealed with a tracer such as silver nitrate using transmission (TEM) or scanning electron microscopy (SEM). Tracer infiltration in the absence of a physical interfacial gap has been referred to as nanoleakage [4], which may occur in interfaces bonded with either etch-and-rinse or self-etch adhesives. Field emission-SEM (FE-SEM) and TEM studies showed that entrapment of water within adhesive interfaces may create additional voids or tracks that could be revealed by these tracers [7][8][9].

Collagen Fiber Network Infiltration: Permeability and Capillary Infiltration

“…So, it is believed that changing the network into a VERT network can enhance infiltration. Using this idea, Pasquantonio et al (2007) applied an electric field to demineralized dentin and showed that it improved bonding. One of the possible reasons could be that the field is reorienting the network into a VERT network.…”

ElectroBond application may improve wetting characteristics of etched dentine

“…18 Incomplete infiltration by the adhesive resins through the demineralized zone may result in unprotected collagen and carbonated apatite crystallites that are vulnerable to enzymatic degradation and acid dissolution, respectively. 1,9,10,22,23 Nevertheless, despite the finding that the use of continuous electric current during adhesive application increased microtensile bond strength and reduced interfacial nanoleakage expression, [18][19][20][21] no conclusive hypotheses on the mechanisms sustaining the bonding increase were provided. It has been hypothesized that electricity may either affect surface wettability or directly influence adhesive monomer impregnation through iontophoretic forces that are superimposed to the polar monomers contained in the resin blends of the modern adhesive system.…”

“…16,17 Recent studies revealed that a new electric device (ElectroBond; SETI, Rome, Italy) could be useful to improve resin infiltration of etch-and-rinse and self-etch adhesives. [18][19][20][21] The rationale for applying a dentine adhesive under an electric current is to improve adhesive infiltration of the demineralized dentine. 18 Incomplete infiltration by the adhesive resins through the demineralized zone may result in unprotected collagen and carbonated apatite crystallites that are vulnerable to enzymatic degradation and acid dissolution, respectively.…”

The Role of Host‐derived Dentinal Matrix Metalloproteinases in Reducing Dentin Bonding of Resin Adhesives

“…Long-term bonding is threatened by disaggregation of the hybrid layer owing mainly to the activation of dentin MMPs. Several methods have been suggested to achieve superior infiltration of monomers, to inhibit the breakdown of collagen fibrils, and to reduce aging water sorption, for example: using hydrophobic adhesives following the use of all-in-one adhesive primers, which have a low level of water sorption and solubility King et al, 2005), application of multiple layers , lengthening the curing time (Cadenaro et al, 2005;Cadenaro et al, 2006), increasing solvent evaporation (van Landuyt et al, 2005) and using electric current (Pasquantonio et al, 2007).…”