Nanoleakage Inhibition Within Hybrid Layer Using New Protective Chemicals and Their Effect on Adhesion

Abstract

Hybrid-layer degradation occurs because of acidic properties of currently used adhesive systems. Titanium tetrafluoride couples with tooth surface, and titanium compounds are not substituted. Caffeic acid phenethyl esther inhibits endogenous matrix metalloproteinases that cause hybrid-layer degradation. It was hypothesized that titanium tetrafluoride and caffeic acid phenethyl esther application on exposed dentine surfaces before adhesive applications would inhibit nanoleakage and hybrid-layer degradation without compromising the bond strength of the adhesives. In ultracut thin sections, human dentinechemical agent-adhesive composite interfaces were observed under transmission electron microscope with complementary scanning electron microscopy. Microtensile bond strength tests were also accomplished. Titanium tetrafluoride and titanium tetrafluoride + caffeic acid phenethyl esther applications decreased bond strength values. Caffeic acid phenethyl esther showed decreased silver nitrate penetration for cements based on Bisphenol glycydilmethacrylate and methyl methacrylate, whereas cement based on 4-methacryloyloxyethyl trimellitate anhydride methyl methacrylate showed almost no infiltration. Caffeic acid phenethyl esther application before cementation could inhibit nanoleakage and biodegradation of the hybrid layer. ABSTRACT Hybrid-layer degradation occurs because of acidic properties of currently used adhesive systems. Titanium tetrafluoride couples with tooth surface, and titanium compounds are not substituted. Caffeic acid phenethyl esther inhibits endogenous matrix metalloproteinases that cause hybrid-layer degradation. It was hypothesized that titanium tetrafluoride and caffeic acid phenethyl esther application on exposed dentine surfaces before adhesive applications would inhibit nanoleakage and hybridlayer degradation without compromising the bond strength of the adhesives. In ultracut thin sections, human dentine-chemical agent-adhesive composite interfaces were observed under transmission electron microscope with complementary scanning electron microscopy. Microtensile bond strength tests were also accomplished. Titanium tetrafluoride and titanium tetrafluoride + caffeic acid phenethyl esther applications decreased bond strength values. Caffeic acid phenethyl esther showed decreased silver nitrate penetration for cements based on Bisphenol glycydilmethacrylate and methyl methacrylate, whereas cement based on 4-methacryloyloxyethyl trimellitate anhydride methyl methacrylate showed almost no infiltration. Caffeic acid phenethyl esther application before cementation could inhibit nanoleakage and biodegradation of the hybrid layer.

Nanomechanical properties, SEM, and EDS microanalysis of dentin treated with 2.5% titanium tetrafluoride, before and after an erosive challenge

“…Titanium tetrafluoride and CA solution preparation The 2.5% TiF 4 solution of pH 1.2 was prepared as suggested by D€ undar et al 9 and used by Bridi et al 11 A portion of 2.5 g of titanium tetrafluoride powder (Sigma Aldrich, Saint Louis, MO) was weighed and mixed in 100 mL of ultra pure water. The pH of the solution was measured by a pH electrode (Seven Multi, Mettler Toledo GmbH, Schwerzenbach, Switzerland).…”

“…For the control group, specimens were left undisturbed until the acidic challenge was performed. For the specimens from the experimental group, the TiF 4 solution was applied on the dentin surfaces with a disposable brush for 60 s, actively, 9,11,22 and then washed with distilled water for 30 s to remove any residues that could interfere with the nanohardness measurements. Next, all specimens were submitted to the erosive challenge with the 0.3% CA solution.…”

“…[9][10][11] Its beneficial effects on dentin can be attributed to the formation of an acid-stable surface layer, by providing mechanical protection to the surface and also by reducing demineralization of dental hard tissues. 12 Sen and B€ uy€ ukyilmaz 13 reported that the presence of a modified layer of TiF 4 after application on dentin may reduce microleakage by preventing further dissolution and disintegration of the smear layer.…”

“…D€ undar et al 9 hypothesized that TiF 4 application as a dentin pretreatment before adhesive application would prevent the effect of enzymatic activity on dentin and inhibit nanoleakage and hybrid layer degradation. With this in mind, a mixed layer with the diffusion of a self-adhesive concomitantly to TiF 4 in dentin could form the hybrid layer.…”

Nanotechnology in dentistry: prevention, diagnosis, and therapy

“…The MMP inhibitor has been used as a separate dentin preconditioning step or included within the resin adhesive monomer. Examples of these inhibitors include benzalkonium chloride, 8 galardin, 26 BB94 and GM6001, 27 chlorhexidine digluconate 28,29 and ZnO particles, 30 ethylenediaminetetraacetic acid, 31 sodium oxalate, 32 titanium tetrafluoride and caffeic acid phenethyl ether, 33 and phosphoric acid/sodium hypochlorite (NaOCl) mixture. 34 Self-healing adhesives, capable of closing micro-or nanocracks before destroying the integrity of resin-dentin bonds, have been also introduced.…”