Evaluation of the time-dependent osteogenic activity of glycerol incorporated magnesium oxide nanoparticles in induced calvarial defects

Versatile application of magnesium-related bone implants in the treatment of bone defects

Magnesium-related bone implants have garnered significant attention in the treatment of bone defects. The applications of magnesium in promoting bone repair mainly include degradable magnesium-based scaffolds owing to its special physical properties and composite materials modified by magnesium ions because of its biological activity. Although numerous studies have confirmed the unique application advantages and efficacy of magnesium in promoting bone repair, some obvious shortcomings persist, including the rapid degradation of magnesium-based scaffolds. In this review, the deficiencies of magnesium and its alloys in the construction of orthopedic implants and their key influencing factors were summarized; furthermore, some advanced improvement schemes were summarized and analyzed. Additionally, the application strategies of magnesium-modified bone implants are summarized and discussed. Lastly, this review incorporates the latest research and discoveries on magnesium in orthopedic science, comprehensively exploring the mechanism of magnesium's role in the complex microenvironment of bone defects from multiple dimensions. This paper provides a comprehensive summary and analysis of cutting-edge concepts in the design and development of magnesium-based bone implants, considering various perspectives such as the physical properties and biological functions of magnesium.

Maximizing dental composite performance: Strength and hardness enhanced by innovative polymer-coated MgO nanoparticles

INTRODUCTION

Zein-incorporated magnesium oxide nanoparticles (zMgO NPs) can influence the mechanical properties of dental materials. However, the effect of this addition on the mechanical properties of resin composite has yet to be investigated. The objective of this study was to add various concentrations of zMgO NPs to conventional, flowable, and bulk-fill composite and assess the effect on the compressive strength, flexural strength, and microhardness.

METHODOLOGY

150 samples each of conventional composite, flowable composite, and bulk-fill composite (n = 450) were enhanced with concentrations of zMgO NPs at 0 %, 0.3 %, 0.5 %, 1 %, and 2 % (n = 30). 10 samples of each group were randomly allotted to the compressive strength, flexural strength, or hardness test. Characterization of the specimens was performed by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. Two-way ANOVA test was used to compare between groups, and one-way ANOVA followed by Tukey's test was done at p = 0.05 to determine significance.

RESULTS

Characterization yielded a uniform distribution of nanoparticles in the matrix and the formation of a new hybrid composite that maintained its properties. Composite of all types enhanced with 0.3 % and 0.5 % zMgO NPs demonstrated a statistically significant increase in compressive strength, flexural strength, and hardness when compared to the control (p < 0.05). The bulk-fill composite with zMgO NPs concentrations of all groups demonstrated a statistically significant increase (p < 0.05) in hardness when compared to the control.

CONCLUSION

The modified composites' compressive strength, flexural strength, and hardness improved or remained consistent.

CLINICAL SIGNIFICANCE

An improved dental resin composite will enhance the quality of care and patient experience. The augmented strength and hardness of resin composite is desirable in prolonging the durability of the restoration.

Enhanced Antimicrobial Properties of Polymeric Denture Materials Modified with Zein-Coated Inorganic Nanoparticles

Background

Polymeric denture materials can be susceptible to colonization by oral microorganisms. Zein-coated magnesium oxide nanoparticles (zMgO NPs) demonstrate antimicrobial activity. The aim of this study was to investigate the antimicrobial effect and adherence of different oral microorganisms on hybrid polymeric denture materials incorporated with zMgO NPs.

Methods

Five types of polymeric denture materials were used. A total of 480 disc-shaped specimens were divided by material type (n=96/grp), then subdivided by zMgO NPs concentration: control with no nanoparticles and other groups with zMgO NPs concentrations of 0.3%, 0.5% and 1% by weight. Characterization of the polymeric denture materials incorporating zMgO NPs was done, and the antimicrobial activity of all groups was tested against four types of microorganisms: 1) Streptococcus mutans, 2) Staphylococcus aureus, 3) Enterococcus faecalis and 4) Candida albicans. The samples underwent an adherence test and an agar diffusion test. Experiments were done in triplicates.

Results

The characterization of the hybrid samples revealed variation in the molecular composition, as well as a uniform distribution of the zMgO NPs in the polymeric denture materials. All hybrid polymeric denture materials groups induced a statistically significant antimicrobial activity, while the control groups showed the least antimicrobial activity. The agar diffusion test revealed no release of the zMgO NPs from the hybrid samples, indicating the NPs did not seep out of the matrix.

Conclusion

The zMgO NPs were effective in reducing the adherence of the tested microorganisms and enhancing the antimicrobial activity of the polymeric denture materials. This antimicrobial effect with the polymeric dentures could aid in resisting microbial issues such as denture stomatitis.

Development and characterization of novel magnesium oxide nanoparticle-impregnated chitosan-based guided tissue regeneration membrane - An in vitro study

Introduction

Although a lot of commercially available guided tissue regeneration (GTR) membranes are used, none of them could actually ensure complete bone regeneration so far and they also have certain limitations. This study aims to explore further and develop a membrane that might overcome these limitations and aid in bone regeneration for the treatment of bony defects.

Materials and Methods

Magnesium oxide nanoparticles (MgONPs) were prepared from magnesium nitrate prepared by calcination at different temperatures and dried using filter paper under specific temperature. Later, 0.3 ml of 0.2 M 1% acetic acid was added to water and placed in the stirrer for at least 1 h. Chitosan (CS) (2%) of two different concentrations containing 0.588 g and 0.576 g of CS, respectively, was prepared and added to the previous mixture. To these concentrations, the prepared MgONPs were added and stirred using a magnetic stirrer for 1 h. Later, it was cast in the mold and dried. The prepared membrane was immersed in 1 M sodium hydroxide to neutralize acetic acid. After preparation, they were subjected to scanning electron microscope (SEM) analysis, energy-dispersive X-ray (EDAX), Fourier transform infrared spectroscopy (FTIR), and contact angle test.

Results

In SEM analysis, spherical in size, uniformly dense, and porous agglomeration was noticed. EDAX and FTIR revealed the formation of MgONPs (magnesium oxide) in the membrane. The average contact angles of the CS with MgONPs and control membranes were 85.48° and 80.80°, respectively. Degradation analysis showed that test membrane showed a slower degradation rate than control collagen membrane at the end of the 28th day.

Conclusion

On comparing membranes with pure CS, membranes with nanoparticles, and control collagen membranes, the membrane incorporated with nanoparticles showed more favorable positive outcomes.

Noninvasive assessment of novel nanohybrid resin cement adaptation using cross-polarization optical coherence tomography

OBJECTIVES

Zein-coated magnesium oxide nanoparticles (zMgO NPs) can potentially improve cement adaptation to the tooth-restoration interface, which would aid in minimizing marginal leakage and secondary caries. The aim of this study was to assess the effect of incorporating zMgO NPs on the adaptation of self-adhesive resin cement using cross-polarization optical coherence tomography (CP-OCT) and scanning electron microscopy (SEM).

METHODS

Resin inlays were fabricated to be cemented in Class-I cavities of extracted human molars. All specimens were randomly divided into five groups (n = 10), and the resin inlays were cemented using self-adhesive resin cement with various concentrations of zMgO NPs (0% [control], 0.3%, 0.5%, 1%, 2%). Characterization was done by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and SEM. The specimens were examined for interfacial adaptation under CP-OCT. Floor and wall adaptation measurements were analyzed by software on 20 B-scans, and samples were sectioned for interfacial measurement by SEM.

RESULTS

Results for CP-OCT and SEM showed a statistically significant increase of adaptation in the floor and wall of resin cement filled with zMgO NPs compared to the control. The samples enhanced with 0.3% and 0.5% showed a statistically significantly better adaptation in floor and wall in CP-OCT and SEM. However, there was no significant difference between the 1%, 2%, and control groups for CP-OCT and SEM analysis.

SIGNIFICANCE

The incorporation of zMgO NPs in self-adhesive resin cement can enhance the cement's properties by significantly improving its wall and floor adaptation.

In Vivo Evaluation of Regenerative Osteogenic Potential Using a Human Demineralized Dentin Matrix for Dental Application

BACKGROUND

The use of a demineralized dentin matrix (DDM) has garnered substantial importance in dentistry. This study was carried out to evaluate the osteoinductive performance of DDM in comparison to nano-hydroxyapatite (n-HA) on calvarial critical-sized bone defect.

METHODS

Two critical-sized defects (CSDs) were bilaterally trephined in the calvarium of sixteen healthy white rabbits. The rabbits were categorized into four groups: in group 1, the defect was left empty; in group 2, defects were filled with sodium alginate (SA) hydrogel as a sole material; in group 3, defects were treated with nano-hydroxyapatite hydrogel (NHH); in group 4, defects were treated using demineralized dentin matrix hydrogel (DDMH). Histological and immunohistochemical analyses were carried out to evaluate the total areas of newly formed bone.

RESULTS

The DDMH group showed that new woven bone tissue progressively bridged the defect area while there was no bone in the control group. Collagen expression was significantly different in the DDMH- and NHH-treated groups compared to in the SA group at 4 and 8 weeks (p < 0.01). OCN expression was significantly higher in the DDMH group in comparison to in the NHH or SA groups at 8 weeks (p < 0.01).

CONCLUSIONS

The DDMH group exhibited significantly higher levels of new bone formation compared to the NHH group at both 4 and 8 weeks post-surgically.