Assessment of Hydroxyapatite Nanospheres Incorporated Dentin Adhesive. A SEM/EDX, Micro-Raman, Microtensile and Micro-Indentation Study

Rana S Al-Hamdan,Hiba F Kattan,Saad Alresayes,Fahim Vohra,Tariq Abduljabbar,Basil Almutairi

doi:10.3390/coatings10121181

Rana S Al-Hamdan, Hiba F Kattan + Show 4 more

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https://doi.org/10.3390/coatings10121181

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Abstract

Hydroxyapatite (HA) delivery with resin adhesives has potential for re-mineralization of resin–dentin interface. The study prepared an adhesive containing HA and confirmed its presence in adhesive and interaction with the dentin using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Micro-Raman spectroscopy. The aim was to assess the influence of HA incorporation in dentin adhesive on its microtensile bond strength (μ-tbs) and Knoop microhardness (KHN). Thirty teeth each were bonded with CA and HA adhesive using a 10-s smear and photo-polymerized. The specimens in each adhesive group (CA and HA) were divided into sub-groups of 24 h, 8 weeks, and 16 weeks (n = 10) aging durations. μ-tbs was assessed at a crosshead speed of 0.5 mm/minute and bonded interface was analyzed using SEM (n = 20) and Raman spectroscopy (n = 10). Softening of HA adhesive and CA was assessed using KHN. HA adhesive presented higher μ-tbs compared to CA. With an increase in storage time, HA adhesive presented with 100% adhesive failure. Softening was less and KHN was higher for HA adhesive compared to CA (p < 0.05). KHN reduction was higher in CA [19.6 (5.1)%] compared to the HA adhesives [9.7 (4.5)%]. HA adhesive showed superior μTBS and microhardness compared to CA. In the absence of nanoleakage, HA modified adhesive exhibited enhanced bond integrity and better durability of resin dentin bond compared to control adhesive.

Highlights

In recent times, the incorporation of nanofillers has led to a change in the paradigm of restorative dentistry
Coatings 2020, 10, 1181 understanding of dentin bonding, incorporation of fillers in the adhesive systems is recommended to reduce water sensitivity, solubility and enhance the mechanical properties of the adhesive and hybrid layer [3]
The HA particles can be regarded as nanospheres with crystal size ranging on the observation, the HA particles can be regarded as nanospheres with crystal size ranging well well below

Summary

Introduction

The incorporation of nanofillers has led to a change in the paradigm of restorative dentistry. The addition of organic and inorganic fillers has shown distinct alteration in the mechanical and adhesive properties of the material, such as microhardness, wear resistance, water sorption, and solubility [1]. Dentin adhesives are resin-based, formulated with monomers including, 2-hydroxyethyl methacrylate (HEMA), bisphenol A glycol dimethacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) without additional fillers [2]. Coatings 2020, 10, 1181 understanding of dentin bonding, incorporation of fillers in the adhesive systems is recommended to reduce water sensitivity, solubility and enhance the mechanical properties of the adhesive and hybrid layer [3]. The bond strength of the adhesive to dentin is weaker compared to enamel due to lower organic content in the dentin. Tooth adhesion critically depends on the dentin substrate and the quality of adhesive polymer [4]

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