Effect of 4-Acryloxyethyltrimellitic Acid in a Self-etching Primer on Bonding to Ground Dentin

Abstract

To develop a self-etching primer for ground dentin, 4-acryloxyethyltrimellitic acid (4-AET) was newly synthesized, and the effect of concentrations varying from 0 (control) to 56.5wt% 4-AET in the water/ HEMA primer on bonding to the dentin was investigated. Bond strength to the dentin was significantly affected by the inclusion of 4-AET in the primer which also contained N, N-di(hydroxyethyl)-p-toluidine (DEPT) when compared with the control (0% 4-AET) (p<0.01). The optimum 4-AET-concentration and the mean bond strength (SD) were found to be 6.5wt%: 24.2 (3.6)MPa, 37.4wt%: 25.3 (4.4)MPa, 47.2wt%: 26.9 (11.6)MPa and 54.4wt%: 29.7 (12.9)MPa. The role of DEPT in the 4-AET/HEMA primer was assessed, and the optimum DEPT-concentration was found to be 0.154 and 0.307mol%. Regarding the hypothetical bonding mechanism to dentin, it was thought that the ionized 4-AET in water/HEMA would penetrate into dentin substrates, and DEPT as an accelerator in situ would facilitate photo-polymerization at the dentin-resin interface, and result in increased bond strength to ground dentin.

Design of a new self-etching HEMA-free adhesive

“…Preparation of reagents 6-MHPA 19) , 4-AET 20) , and 2,2'-bis[4(2-hydroxy-3 methacryloyloxy propoxy)phenyl]propane (=bisphenol A-diglycidyl methacrylate) (Bis-GMA) 21) were synthesized according to the respective methods previously reported. Ethylene glycol dimethacrylate (EGDMA) and triethylene glycol dimethacrylate (TEGDMA) (EGDMA, TEGDMA: Shin-Nakamura Chemicals Co. Ltd., Wakayama, Japan), DL camphorquinone (CQ) (Tokyo Chemical Industry Co. Ltd., Tokyo, Japan), ethyl-p-dimethylaminobenzoate (EDAB), and 1 mol/l sodium hydroxide (1N NaOH) solution (EDAB, 1N NaOH: Wako Pure Chemicals Industries Ltd., Osaka, Japan) were purchased and used without further purification.…”

“…To circumvent the hydrolytic degradation of selfetching adhesives, however, this study focused on the effect of the degree of ionization of self-etching adhesives on their formulation stability. The aim of this study, therefore, was to investigate the effect of the pH value of single-bottle self-etching HEMA-free adhesives comprising 6-methacryloyloxyhexyl phosphonoacetate (6-MHPA) 19) and 4-acryloyloxyethyltrimellitic acid (4-AET) 20) on adhesion to ground and unetched enamel and dentin, using adhesives artificially aged in air at 50°C for 6 weeks. In addition, micromorphological investigation of the resin-tooth bonding interface was performed.…”

Clinical application of adhesive systems - a critical review: biomimetic approach

“…These were the main factors that led researchers to develop systems which could impregnate the substrate with monomers at the same time as they would promote demineralization of the tissue. These compounds, known as self-etching, were initially presented in two bottles whereby an acid primer was applied and subsequently a hydrophobic acid would perform the hybridization [21][22] . In this way, decalcified, non-mineralized zones would cease to occur, significantly reducing post-operative sensitivity.…”

“…In 1996, Ikemura et al [21][22] presented their study on systems based on self-etching primers (this should be understood as "etching of the substrate promoted by its own adhesive system"). The possibility of the formation of hybrid layers using these systems was demonstrated.…”

Influence of light irradiation on Vickers hardness of dual-cure cement polymerized under restorations

“…This meant that Vaseline did not affect the polymerization of the primer or resin cement. For this reason and in compliance with the clinical practice of phosphoric acid etching of enamel, a separating medium was finally employed on bovine enamel surfaces prior to the application of a selfetching primer 22) (Table 3) which contained DEPT as a polymerization accelerator 23) . Application of the selfetching primer also improved the polymerization of dualcure cement in areas covered by the restoration.…”