Does Modification of Amalgomer with Propolis Alter Its Physicomechanical Properties? An In Vitro Study

A self-healing crosslinked-xanthan gum/soy protein based film containing halloysite nanotube and propolis with antibacterial and antioxidant activity for wound healing

Traumatic multidrug-resistant bacterial infections are the most threat to wound healing. Lower extremity wounds under diabetic conditions display a significant delay during the healing process. To overcome these challenges, the utilization of protein-based nanocomposite dressings is crucial in implementing a successful regenerative medicine approach. These dressings hold significant potential as polymer scaffolds, allowing them to mimic the properties of the extracellular matrix (ECM). So, the objective of this study was to develop a nanocomposite film using dialdehyde-xanthan gum/soy protein isolate incorporated with propolis (PP) and halloysite nanotubes (HNTs) (DXG-SPI/PP/HNTs). In this protein-polysaccharide hybrid system, the self-healing capability was demonstrated through Schiff bonds, providing a favorable environment for cell encapsulation in the field of tissue engineering. To improve the properties of the DXG-SPI film, the incorporation of polyphenols found in PP, particularly flavonoids, is proposed. The synthesized films were subjected to investigations regarding degradation, degree of swelling, and mechanical characteristics. Additionally, halloysite nanotubes (HNTs) were introduced into the DXG-SPI/PP nanocomposite films as a reinforcing filler with varying concentrations of 3 %, 5 %, and 7 % by weight. The scanning electron microscope (SEM) analysis confirmed the proper embedding and dispersion of HNTs onto the DXG-SPI/PP nanocomposite films, leading to functional interfacial interactions. The structure and crystallinity of the synthesized nanocomposite films were characterized using Fourier Transform Infrared Spectrometry (FTIR) and X-ray diffraction (XRD), respectively. Moreover, the developed DXG-SPI/PP/HNTs nanocomposite films significantly improved cell growth of NIH-3T3 fibroblast cells in the presence of PP and HNTs, indicating their cytocompatibility. The antibacterial activity of the nanocomposite was evaluated against Escherichia coli (E. Coli) and Staphylococcus aureus (S. Aureus), which are commonly associated with wound infections. Overall, our findings suggest that the synthesis of DXG-SPI/PP/HNTs nanocomposite scaffolds holds great promise as a clinically relevant biomaterial and exhibits strong potential for numerous challenging biomedical applications.

Development of Newly Formulated Nanoalumina-/Alkasite-Based Restorative Material

Purpose

Nanotechnology offers considerable scope in dentistry to improve dental treatment, care, and prevention of oral diseases through the use of nanosized biomaterials. This study assessed the effect of incorporating alumina nanoparticles (Al₂O₃ NPa) to the recently introduced alkasite-based restorative material (Cention N) on its mechanical properties and surface topographical features.

Materials and Methods

Alumina nanopowder was incorporated into the powder component of Cention N at 5 and 10% (w/w). The unblended powder was used as a control. Compressive strength was assessed using a universal testing machine. Surface microhardness and roughness were evaluated using the Vickers microhardness test and surface profilometer, respectively. Surface topography was inspected using a scanning electron microscope (SEM). Data were analyzed by ANOVA and Tukey's test (P < 0.05).

Results

Incorporation of either 5 or 10% (w/w) Al₂O₃ NPa into alkasite-based restorative materials (Cention N) increased both its compressive strength and surface microhardness. This increase was significant with the use of lower concentration Al₂O₃ NPa (5% w/w). Meanwhile, there was an increase in surface roughness values of Cention N modified with either 5 or 10% (w/w) Al₂O₃ NPa. This increase was only significant in the case of 10% (w/w) Al₂O₃ NPa.

Conclusion

Incorporation of 5% (w/w) Al₂O₃ NPa into the newly introduced alkasite-based restorative material (Cention N) seems to produce a promising restorative material with high compressive strength and surface hardness without adversely affecting its surface roughness properties. Thus, nanotechnology implementation into Cention N restorative material may be strongly helpful for a diversity of clinical applications.

Surface Analysis and Spectrophotometric Evaluation of Different Esthetic Restorative Materials Frequently Exposed to a Desensitizing Agent

Background

Patients with tooth sensitivity are frequently exposed to desensitizing agents on a regular basis. These agents might have an impact on the surface properties and color of existing oral restorations. Accordingly, this study aimed to investigate the color stability, surface microhardness, and surface roughness of resin-modified glass ionomer (RMGIC), amalgomer CR, nanohybrid, and bulk-fill resin composites restorative materials after frequent exposure to a desensitizing agent. Materials and Methods. One hundred and twenty specimens were prepared; 10 specimens for each restorative material were equally subdivided into control and desensitizing-agent-exposed groups in each test. Surface microhardness and surface roughness were evaluated using the Vickers microhardness tester and surface profilometer, respectively. The color change was measured by using a spectrophotometer using the CIE L^∗a^∗b^∗ formula. Surface topography was analyzed using a scanning electron microscope (SEM). The collected data were analyzed with Student's t-test, one-way ANOVA, and Tukey post hoc tests for pairwise comparison at a level of significance of 0.05.

Result

The frequent use of a desensitizing agent significantly decreased surface hardness of RMGIC, amalgomer, and bulk-fill composite materials. However, nanohybrid composite exhibited a significant surface hardness increase. The surface roughness of RMGIC, amalgomer, and nanohybrid composite increased significantly. Meanwhile, the bulk-fill resin composite showed a nonsignificant decrease. Both RMGIC and amalgomer exhibited significantly higher values of color change in comparison to those of nanohybrid and bulk-fill composites.

Conclusion

The bulk-fill composite seems to be more resistant to discoloration and surface topographical changes than other tested materials on frequent exposure to the desensitizing agent. However, this exposure may pose a negative impact on its surface hardness. Bulk-fill resin composite may be the most suitable esthetic restorative in patients who frequently use desensitizing agents.