Polyethylene-glycol coated maghemite nanoparticles for treatment of dental hypersensitivity
Introduction
Dental hypersensitivity is defined as “a short sharp pain arising from exposed dentin in response to stimuli typically thermal, evaporative, tactile, osmotic, or chemical and which cannot be ascribed to any other form of defect, pathology, or disease” [1]. In other words, it means a painful response to stimuli(s) that is not normally associated with pain [2]. The main cause of dental hypersensitivity is open dental tubules (microscopic channels in the dentin), which serve as direct links between the external environment and the pulp. Previous studies have demonstrated that the dental tubules in hypersensitive dentins are larger in both number and diameter compared to non-sensitive dentin [3]. Therefore, it can correctly be assumed that the severity of dental hypersensitivity is related to the number and width of dental tubules.
Dental tubule occlusion is one of the principal strategies for the treatment of dental hypersensitivity which involves the use of compounds that can precipitate inside the tubules and plug their orifices. However, the micron-sized diameter of dental tubules presents a physiological limitation for diffusion of large therapeutic compounds. Therefore in this protocol, fine particle size is crucial as it allows a faster and deeper deposition of particles inside the dental tubules. Based on this fact, several biomaterials have been synthesized in the nanoscale for treatment of dental hypersensitivity, including gold [4], hydroxyapatite [5], carbonate apatite [6], calcium oxide–mesoporous silica [7], and nanolipid carriers [8]. Although these agents have yielded promising results, the navigation of such nanoparticles inside the tubules remains a challenge [9].
In this research, we have studied the possibility of using polyethylene-glycol coated maghemite nanoparticles (PEG-MNPs) for treating dental hypersensitivity. We assumed that the maghemite nanoparticles (MNPs) could be navigated inside the tubules via an external magnetic field. The PEG coating acts as a protective layer for minimizing the aggregation and biofouling of MNPs in physiological conditions for long periods [10], [11], [12]. The biocompatibility of both PEG and maghemite compounds makes the PEG-MNPs attractive candidates for the fast and effective treatment of dental hypersensitivity.
Section snippets
Materials and methods
Maghemite nanoparticles were synthesized via the modification of the recipes described in literature [13], [14]. In our method, the synthesis was performed in an aqueous medium and air atmosphere (instead of nitrogen) for a more facile production of nanoparticles. In a typical synthetic process, 1.0 mL of 2 M ferrous sulfate heptahydrate (FeSO4·7H2O) and 3.5 mL of 1 M ferric chloride (FeCl3) were mixed in 25 mL of distilled water, and then 25 mL of ammonium hydroxide (NH4OH, 33% NH3 in water)
Results and discussion
Fig. 1a shows a TEM image of the synthesized nanoparticles. The diameter of the nanoparticles was mostly smaller than 25 nm, which was suitable for filling the dental tubules. The photomicrograph of a typical untreated specimen is shown in Fig. 1b, which presents a smooth dentin surface without any smear layer covering the tubules׳ orifices.
Fig. 2 shows the SEM images of the M60 samples before rinsing with water. This figure presents two significant modes of tubular occlusion by PEG-MNPs before
Conclusion
In this study, the permeability of polyethylene-glycol coated maghemite nanoparticles into dental tubules was examined via an external magnetic field. Moreover, the effect of exposure time to external magnetic field on the occlusion ratio of the tubules was also investigated. The results of this study provide a confirmation of the research hypothesis that polyethylene-glycol coated maghemite nanoparticles are able to occlude the open dental tubules, and could be used in dental hypersensitivity
Acknowledgments
We wish to thank the Ministry of Science, Technology and Innovation (MOSTI) Malaysia (Science fund: 06-01-03-SF0587) and University of Malaya (Research Grant No: RG055/09HTM) for financing this project. The authors state no conflict of interest.
References (14)
- et al.
Preparation of PEG-grafted silica particles using emulsion method
Mater Lett
(2005) - et al.
Facilely dispersible magnetic nanoparticles prepared by a surface-initiated atom transfer radical polymerization
Mater Lett
(2008) - et al.
Synthesis and characterization of stable dicarboxylic pegylated magnetite nanoparticles
Mater Lett
(2013) - et al.
Synthesis of magnetite (Fe3O4) nanoparticles without surfactants at room temperature
Mater Lett
(2007) Synthesis of maghemite (γ-Fe2O3) nanoparticles by wet chemical method at room temperature
Mater Lett
(2010)- et al.
Guidelines for the design and conduct of clinical trials on dentine hypersensitivity
J Clin Periodontol
(1997) - et al.
Clinical dentin hypersensitivity: understanding the causes and prescribing a treatment
J Contemp Dent Pract
(2001)
Cited by (13)
Smart dental materials for antimicrobial applications
2023, Bioactive MaterialsCitation Excerpt :In the presence of an external magnetic field, the microemulsion can be driven to penetrate deep sites inside the biofilms, resulting in an improved antimicrobial activity against S. mutans and saliva-derived multispecies biofilm compared with only photodynamic disinfection [301]. The transport of PEG/Fe3O4 NPs inside the dental tubules via an external magnetic field showed successful results in occluding dentinal tubules to treat dental hypersensitivity [302]. The SPION was also employed in adhesive dentistry for bonding optimization.
Advances in the Development of Biodegradable Polymeric Materials for Biomedical Applications
2022, Encyclopedia of Materials: Plastics and PolymersRecent advances of gold nanoparticles as biomaterial in dentistry
2020, International Journal of PharmaceuticsCitation Excerpt :Polymeric and Chitosan nanoparticle delivery systems have been used for release of chlorhexidine for antibacterial effects and bone morphogenic proteins for regeneration of tissues (Chronopoulou et al., 2016)(Bastami et al., 2017). These have also been used to as drug carriers to treat hypersensitive teeth and periodontal regeneration(Dabbagh et al., 2014). Porcelain’s fracture resistance is increased by addition of platinum and silver nanoparticles(Fujieda et al., 2012).
The use of nanoparticles as biomaterials in dentistry
2019, Drug Discovery TodayCitation Excerpt :The specimens that were treated with these MNPs for 2 h showed the highest occlusion of tubules. Thus, PEG-MNPs can be used to treat dental hypersensitivity because they tightly seal the tubules with relatively fast diffusion [89]. Priyadarshini et al. analyzed the in vitro and ex vivo effects of novel PCL nanocapsules (nano-PCL) loaded with CHX in various ratios compared with unloaded nanocapsules.
Controlled release of chlorhexidine from a HEMA-UDMA resin using a magnetic field
2018, Dental MaterialsCitation Excerpt :Recent studies have demonstrated that by using a magnetic field superparamagnetic iron oxide nanoparticles are able to target infection sites, inhibit several bacterial functions and penetrate biofilms; thereby overcoming the therapeutic barrier often encountered when using traditional antibiotics or other antibacterial agents [3,9]. In dentistry, magnetic nanoparticles have been incorporated into polymeric scaffolds or cement composites to enhance cell adhesion and osteogenic differentiation [15–17] and have been navigated inside dental tubules via an external magnetic field for treating dental hypersensitivity [18]. Magnetic nanoparticles are also combined with other components to enhance their antibacterial performance.
Penetration of sub-micron particles into dentinal tubules using ultrasonic cavitation
2017, Journal of DentistryCitation Excerpt :The majority of the SMPs had deposited on the surface of the dentine and many tubules were partially or completely occluded. Although complete occlusion would be ideal, partial occlusion is also likely to reduce pain because the fluid flow inside the tubules is proportional to the tubule radius to the power 4 (r4) [19]. Doubling the tubule radius therefore causes a 16-fold increase in the fluid flow rate in the tubule, so partial occlusion of the tubule may increase the potential to significantly reduce the pain experience of the patient.