Nanocurcumin Release from Self-Cured Acrylic Resins; Effects on Antimicrobial Action and Flexural Strength

Impact of photodynamic therapy based on modified orthodontic self-cured acrylic resin containing titanium dioxide nanoparticles against Candida albicans

BACKGROUND

This in vitro study was conducted to evaluate the impact of photodynamic therapy (PDT) using modified acrylic resin with titanium dioxide nanoparticles (TiO2NPs) on Candida albicans biofilm, physico-mechanical properties, and pro-inflammatory gene expression.

MATERIALS AND METHODS

The biofilm inhibition test was used to assess the antimicrobial effectiveness against C. albicans biofilm. The levels of gene expression for TNF-α and IL-6 in human gingival fibroblast (HGF) cell line were examined using quantitative real-time polymerase chain reaction (qRT-PCR). The roughness, flexural strength, and microhardness of modified acrylic resin with different concentrations of TiO2NPs (0%, 1%, 2%, and 3%) were measured using a profilometer, a universal testing machine, and a digital hardness tester, respectively.

RESULTS

The C. albicans biofilm was most effectively reduced by 0.2% chlorhexidine (CHX), showing the lowest colony count (5.94 ± 0.46 × 106 CFU/mL). Comparable results were observed with 3% TiO2NPs-PDT (7.37 ± 1.34 × 106 CFU/mL, P = 0.300). The colony counts from 2% TiO2NPs-PDT (9.21 ± 1.25 × 106 CFU/mL) was not significantly different from 3% TiO2NPs-PDT (P = 0.529) but was notably higher than that of 0.2% CHX (P=0.004). The expression of TNF-α and IL-6 genes decreased significantly in HGF cell line when exposed to 2% and 3% TiO2NPs-PDT. Microhardness and flexural strength demonstrated a direct correlation with the concentration of TiO2NPs, while roughness showed an inverse correlation. Additionally, all groups exceeded the ISO standards for flexural strength.

CONCLUSION

3% TiO2NPs-PDT reduced C. albicans biofilm and downregulated the pro-inflammatory gene expression without adversely affecting the properties of the acrylic resin, making it suitable for clinical use.

Biological and mechanical properties of a self-curing acrylic resin enriched with AgNPs as a proposal for orthopedic aparatology

Polymethylmethacrylate (PMMA) is widely used in dentistry, but its inherent characteristics, such as roughness and porosity, can facilitate the formation of bacterial biofilms. However, the integration of silver nanoparticles (AgNPs) can provide antimicrobial properties. Ongoing research endeavors aim to preserve post-nanoaggregation biocompatibility without compromising the mechanical integrity of the material. In this study, we investigated the biological and mechanical attributes of a PMMA nanocomposite infused with AgNPs biosynthesized from Pelargonium × hortorum. A method has been described to incorporate nanoparticles into the polymer at minimum concentrations. In the results, LC-MS-MS revealed the presence of 56 biochemical compounds. UPLCHRESIMS-MS/MS was used to compare the phytochemical profiles of the leaf extract of Pelargonium × hortorum before and after the formation of AgNPs, which were identified with spherical morphology, an absorbance of 28.5 ± 8.16 nm and a particle size of 415 nm. The MIC of AgNPs was 10 μg mL-1. In bacterial MTT, a decrease to 18.2 ± 2.5% with PMMA-10 μg mL-1 was observed (p < 0.05). Decreased cell viability was found only in PMMA-0 μg mL-1 at 89.1 ± 6.7%, indicating no cytotoxicity. These findings suggest a promising bionano material that is suitable for orthodontic and orthopedic devices and warrants further research.

Dynamics of the oral microbiome during orthodontic treatment and antimicrobial advances for orthodontic appliances

The oral microbiome plays an important role in human health, and an imbalance of the oral microbiome could lead to oral and systemic diseases. Orthodontic treatment is an effective method to correct malocclusion. However, it is associated with many adverse effects, including white spot lesions, caries, gingivitis, periodontitis, halitosis, and even some systematic diseases. Undoubtedly, increased difficulty in oral hygiene maintenance and oral microbial disturbances are the main factors in developing these adverse effects. The present article briefly illustrates the characteristics of different ecological niches (including saliva, soft tissue surfaces of the oral mucosa, and hard tissue surfaces of the teeth) inhabited by oral microorganisms. According to the investigations conducted since 2014, we comprehensively elucidate the alterations of the oral microbiome in saliva, dental plaque, and other ecological niches after the introduction of orthodontic appliances. Finally, we provide a detailed review of recent advances in the antimicrobial properties of different orthodontic appliances. This article will provide researchers with a profound understanding of the underlying mechanisms of the effects of orthodontic appliances on human health and provide direction for further research on the antimicrobial properties of orthodontic appliances.

The flexural strength of orthodontic acrylic resin containing resveratrol nanoparticles as antimicrobial agent: An in vitro study

OBJECTIVE

This study aimed to evaluate how the addition of resveratrol nanoparticles (RNPs), which act as an antimicrobial agent, affects the strength of acrylic resin used in orthodontics.

METHODS

According to ISO 20795-1-2013, 76 cold cure acrylic resin samples (65×10×3.3mm) were prepared. The samples were divided into four groups (19 samples in each group) based on RN concentrations added to 1mL acrylic monomer (0 for control, 256, 512, and 1024μg/mL). Flexural strength was assessed in megapascal (MPa) using a universal testing machine. Data analysis involved nonparametric Kruskal-Wallis analysis of variance and pairwise post-hoc Dunn's test.

RESULTS

The flexural strength decreased as the concentration of RNPs increased, with the lowest value observed at 1024μg/mL (63.06±5.33MPa). The control group exhibited the highest mean of flexural strength (88.43±4.41MPa), followed by the groups with RNPs at the concentrations of 256μg/mL (82.69±4.41MPa) and 512μg/mL (76.02±4.59MPa).

CONCLUSION

In conclusion, the addition of RNs to orthodontic acrylic resin had a dose-dependent impact on its flexural strength. Based on the findings, we recommend incorporating RNs at a concentration of 256μg/mL as an antimicrobial agent in orthodontic acrylic resin. However, further research is necessary to assess the long-term effects and clinical applications of this approach.

The effects of antimicrobial photocatalytic nanoparticles on the flexural strength of orthodontic acrylic resins: A systematic review and meta-analysis

BACKGROUND/PURPOSE

Orthodontic acrylic resins containing antimicrobial photocatalytic nanoparticles aims to reduce oral lesions including denture stomatitis and white spot lesions but they should not imperil its mechanical properties. This systematic review was done to evaluate the effect of various photocatalytic nanoparticles on the flexural strength (FS) of acrylic resins.

MATERIALS AND METHODS

We systematically searched the PubMed/Medline, Cochrane Library, and Scopus databases from January 2018 to October 2023. The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the quality of the studies was evaluated using the QUIN tool, which is specifically designed to assess the risk of bias in vitro studies.

RESULTS

Following screening of 1016 initial records, 23 studies were deemed eligible for inclusion. The addition of photocatalytic nanoparticles, such as emodin (Emo), curcumin (Cur), Cur nisin (CurNis), zeolite/zinc oxide (Zeo/ZnO), and Ulva lactuca (U. lactuca), to acrylic resins resulted in a reduction in FS, with the extent of reduction dependent on the nanoparticle concentration. Specifically, the addition of Emo (≥0.5 %), Cur (≥0.5 %), CurNis (≥5 %), Zeo/ZnO (≥2), and U. lactuca (≥1 %) to acrylic resins significantly decreased FS. Conversely, the inclusion of ZnO and titanium dioxide (TiO2) in acrylic resins improved FS, but higher concentrations (≥5 % for TiO2) had a limited positive effect.

CONCLUSION

Our study supports the use of low concentrations of photocatalytic nanoparticles, such as ZnO (≤2 %), TiO2 (≤3 %), Emo (≤0.5 %), Cur (≤0.5 %), CurNis (≤5 %), and U. lactuca (≤1 %), in orthodontic acrylic resins without compromising FS.