Interface evaluation of experimental dental adhesives with nanostructured hydroxyapatite incorporation

Abstract

The aim of this study was to evaluate the adhesive interface with dentin of an experimental adhesive resin with nanostructured hydroxyapatite addition. The organic phase of the adhesive resin was produced by mixing 50 wt.% Bis-GMA, 25 wt.% TEGDMA and 25 wt.% HEMA. CQ and EDAB were added at 1 mol% to all groups, according to the monomer moles. HA nano was added at the following two concentrations: 0 and 2 wt%. One commercial adhesive system was used as control. Nine lower incisor bovine teeth were used to produce interfaces of adhesive resin and dentin. Tooth slices were analysed using the following micro-Raman parameters: a 100 mW diode laser with 785 nm wavelength and spectral resolution of~3-5 cm -1 . One-dimensional mapping was performed over a 150 μm line across the adhesive-dentine interface at 1 μm intervals using a computerized XYZ stage. These areas covered the composite resin, adhesive layer, hybrid layer, partially demineralised and un-affected dentine and were visualised and focused at x500 magnification. Raman analysis showed the penetration of experimental and commercial adhesive systems into dentin. HA nano was observed into the hybrid layer. Based on results of the present study, is possible to observe resin and nanostructured hydroxyapatite penetration at the hybrid layer.

The Use of Montmorillonite Clays as Reinforcing Fillers for Dental Adhesives

“…11,12 Although some researchers have reported the possible use of nanofillers in dental adhesives, their use remains a challenge due to the still limited number of fillers used for this purpose. 6 Therefore, the aim of this study was to investigate the effect of the concentration and type of organomodified montmorillonite clays in the adhesion layer on the mechanical properties of dental adhesives.…”

“…8,9 Besides this, because of their small sizes, nanoparticles are able to penetrate into the tooth micropores, providing a bond layer with improved properties. 6,10 Clay-polymer systems can show improvement of many properties of polymeric matrixes, such as elastic modulus, flexural and tensile properties and heat resistance. Clay systems have many possible morphologies, which include: (1) agglomerated particles, where the layers remain joined and polymer chains only interact with their surface; (2) intercalated, when the polymer chains are between the clay platelets; and (3) exfoliated, when the silicate platelets are isotropically dispersed in the polymeric matrix.…”

“…[3][4][5] Nowadays, inorganic particles are used in their formulation because this improves some physical and mechanical properties. 6,7 Nanoparticles are widely used as reinforcing fillers in composites, since they have a strong impact on properties when incorporated in smaller amounts in comparison with macro/micro fillers. 8,9 Besides this, because of their small sizes, nanoparticles are able to penetrate into the tooth micropores, providing a bond layer with improved properties.…”

A Brief Review on Biomedical Applications of Hydroxyapatite Use as Fillers in Polymer

“…These main class polymers comprise bioresorbable compounds known as alpha-polyesters or poly(alpha-hydroxy) acids [85], and poly (acrylonitrile-co-butadiene-co-styrene) (ABS) [86]. Many studies reported that polymers modified with HA filler improve the mechanical properties, such as tensile strength, flexural strength, impact energy and hardness, as well as biocompatibility of composites [23,27,[87][88][89][90]. This finding can be ascribed to the excellent biocompatibility of HA [91].…”

Mineral deposition at dental adhesive resin containing niobium pentoxide

“…Niobium pentoxide (Nb 2 O 5 , Companhia Brasileira de Metalurgia e Mineração, Araxá, MG, Brazil) was added at 2.5 and 5 wt%, in relation to the mass of the experimental adhesives, and one adhesive without Nb 2 O 5 was used as a control. Nb 2 O 5 was previously silanized using γ-methacryloxypropyltrimethoxysilane (γ-MPTS, Aldrich Chemical Co., Milwaukee, WI, USA) [17]. Reagents were hand mixed and sonicated for 180 s.…”