Dentin Bond Integrity of Hydroxyapatite Containing Resin Adhesive Enhanced with Graphene Oxide Nano-Particles-An SEM, EDX, Micro-Raman, and Microtensile Bond Strength Study.

Yasser F Alfawaz,Hiba F Kattan,Muhammad S Zafar,Fahim Vohra,Basil Almutairi,Tariq Abduljabbar,Mustafa Naseem,Imran Farooq

doi:10.3390/polym12122978

Abstract

The aim was to synthesize and characterize an adhesive incorporating HA and GO nanoparticles. Techniques including scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), micro-tensile bond strength (μTBS), and micro-Raman spectroscopy were employed to investigate bond durability, presence of nanoparticles inside adhesive, and dentin interaction. Control experimental adhesive (CEA) was synthesized with 5 wt% HA. GO particles were fabricated and added to CEA at 0.5 wt% (HA-GO-0.5%) and 2 wt% GO (HA-GO-2%). Teeth were prepared to produce bonded specimens using the three adhesive bonding agents for assessment of μTBS, with and without thermocycling (TC). The adhesives were applied twice on the dentin with a micro-brush followed by air thinning and photo-polymerization. The HA and GO nanoparticles demonstrated uniform dispersion inside adhesive. Resin tags with varying depths were observed on SEM micrographs. The EDX mapping revealed the presence of carbon (C), calcium (Ca), and phosphorus (P) in the two GO adhesives. For both TC and NTC samples, HA-GO-2% had higher μTBS and durability, followed by HA-GO-0.5%. The representative micro-Raman spectra demonstrated D and G bands for nano-GO particles containing adhesives. HA-GO-2% group demonstrated uniform diffusion in adhesive, higher μTBS, adequate durability, and comparable resin tag development to controls.

Highlights

Dental resin composites are among the most utilized restorative materials in dentistry due to superior aesthetics and improved mechanical properties [1]
A mixture of monomers comprising of bisphenol A glycol dimethacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA), 2-hydroxyethyl methacrylate (HEMA), and ethyl 4-dimethylamino benzoate and camphorquinone (Esstech Inc., Essington, PA, USA) were used
The nano-HA particles demonstrated

Summary

Introduction

Dental resin composites are among the most utilized restorative materials in dentistry due to superior aesthetics and improved mechanical properties [1]. Dentin adhesives are employed to bond hydrophobic resin composites to hydrophilic dentin tissue, for dentin preservation and caries resistance [2]. Adhesion with dentin is more challenging for dental adhesives as dentin is less mineralized with high water content compared to enamel, warranting more technique sensitivity [3]. One major reason for the composite restorative failure is loss of adhesive bond over a period of time [5]. This loss of bond leads to the formation of nano-gaps resulting in bond failure and development of secondary caries [6]

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