A Comparative Evaluation on Antimicrobial Effect of Honey, Neem Leaf Extract and Sodium Hypochlorite as Intracanal Irrigant: An Ex-Vivo Study

Poly(Lysine)-Derived Carbon Quantum Dots Conquer Enterococcus faecalis Biofilm-Induced Persistent Endodontic Infections

Introduction

Persistent endodontic infections (PEIs) mediated by bacterial biofilm mainly cause persistent periapical inflammation, resulting in recurrent periapical abscesses and progressive bone destruction. However, conventional root canal disinfectants are highly damaging to the tooth and periodontal tissue and ineffective in treating persistent root canal infections. Antimicrobial materials that are biocompatible with apical tissues and can eliminate PEIs-associated bacteria are urgently needed.

Methods

Here, ε-poly (L-lysine) derived carbon quantum dots (PL-CQDs) are fabricated using pyrolysis to remove PEIs-associated bacterial biofilms.

Results

Due to their ultra-small size, high positive charge, and active reactive oxygen species (ROS) generation capacity, PL-CQDs exhibit highly effective antibacterial activity against Enterococcus faecalis (E. faecalis), which is greatly dependent on PL-CQDs concentrations. 100 µg/mL PL-CQDs could kill E. faecalis in 5 min. Importantly, PL-CQDs effectively achieved a reduction of biofilms in the isolated teeth model, disrupting the dense structure of biofilms. PL-CQDs have acceptable cytocompatibility and hemocompatibility in vitro and good biosafety in vivo.

Discussion

Thus, PL-CQDs provide a new strategy for treating E. faecalis-associated PEIs.

Recent progress in carbon dots for anti-pathogen applications in oral cavity

Background

Oral microbial infections are one of the most common diseases. Their progress not only results in the irreversible destruction of teeth and other oral tissues but also closely links to oral cancers and systemic diseases. However, traditional treatment against oral infections by antibiotics is not effective enough due to microbial resistance and drug blocking by oral biofilms, along with the passive dilution of the drug on the infection site in the oral environment.

Aim of review

Besides the traditional antibiotic treatment, carbon dots (CDs) recently became an emerging antimicrobial and microbial imaging agent because of their excellent (bio)physicochemical performance. Their application in treating oral infections has received widespread attention, as witnessed by increasing publication in this field. However, to date, there is no comprehensive review available yet to analyze their effectiveness and mechanism. Herein, as a step toward addressing the present gap, this review aims to discuss the recent advances in CDs against diverse oral pathogens and thus propose novel strategies in the treatment of oral microbial infections.

Key scientific concepts of review

In this manuscript, the recent progress of CDs against oral pathogens is summarized for the first time. We highlighted the antimicrobial abilities of CDs in terms of oral planktonic bacteria, intracellular bacteria, oral pathogenic biofilms, and fungi. Next, we introduced their microbial imaging and detection capabilities and proposed the prospects of CDs in early diagnosis of oral infection and pathogen microbiological examination. Lastly, we discussed the perspectives on clinical transformation and the current limitations of CDs in the treatment of oral microbial infections.

Can natural irrigants replace sodium hypochlorite? A systematic review

CONTEXT

Sodium hypochlorite, a gold standard for irrigation in endodontics, has disadvantages like toxicity and root dentin weakening. Alternatives derived from natural products are being explored.

AIMS

This systematic review was done to understand the clinical benefits of natural irrigants when compared with a standard irrigant, sodium hypochlorite.

SETTINGS AND DESIGN REGISTRATION

This systematic review was registered with PROSPERO (2018 CRD42018112837) METHODS AND MATERIAL: This review was done in conformation to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA 2020) statement. In vivo studies using at least one natural irrigant and sodium hypochlorite (NaOCl) were included. Studies using them as medicaments were excluded. PubMed, Cochrane and SCOPUS were searched. RevMan tool for Risk of Bias 2 (RoB 2) and risk-of-bias tool to assess non-randomized studies of interventions (ROBINS-I) were used. GRADEpro was used to assess certainty of evidence.

RESULTS

Ten articles (6 RCTs and 4 clinical studies) on approximately 442 patients were included. Seven natural irrigants were evaluated clinically. Due to the heterogeneity, meta-analysis could not be conducted. Antimicrobial efficacy was found to be similar for castor oil, neem, garlic-lemon, noni, papaine and NaOCl. Neem, papaine-chloramine, neem-NaOCl and neem-CHX were superior, while propolis, miswak and garlic were inferior to NaOCl. Post-operative pain was less for neem. There was no significant difference between papaine-chloramine, garlic extract and sodium hypochlorite in clinical/radiographic success.

CONCLUSIONS

The studied natural irrigants are not more efficacious than NaOCl. At the moment, they cannot replace NaOCl routinely and may only substitute in select cases.

What Are the Cleaning and Disinfection Methods for Acrylic Orthodontic Removable Appliance? A Systematic Review

(1) Background: The use of removable orthodontic appliances, which is common in early ages, requires careful hygiene, as several different microorganisms are found on their surface during the orthodontic treatment. (2) Methods: Comprehensive electronic searches were conducted up to May 2021. Randomized controlled trials (RCTs) or controlled clinical trials (CCTs), prospective or retrospective, evaluating the efficacy of cleaning and disinfection methods for acrylic removable orthodontic appliances, redacted in the English language, were included. Three independent blinding review authors were involved in study selection, data extraction, and bias assessment. (3) Results: A total of 2491 records were screened and eight studies (six RCTs and two CCTs) fulfilled the inclusion criteria. Among the overall cleaning and disinfection methods described in the included studies, four categories could be defined: liquid antimicrobial agents, commercial tablet cleansers, natural plant extracts and incorporation of quaternary ammonium methacryloxy silicate, all of which demonstrated superior efficacy compared to the placebo/negative control. However, the different methods were not compared with each other. (4) Conclusions: Biofilm control on acrylic orthodontic removable appliances can be performed using the different cleaning and disinfection methods considered in the included studies. Further studies are needed to define the most effective technique. Registration: PROSPERO CRD 42021269297.

Enhanced Eradication of Bacterial/Fungi Biofilms by Glucose Oxidase-Modified Magnetic Nanoparticles as a Potential Treatment for Persistent Endodontic Infections

Bacterial/fungal biofilm-mediated persistent endodontic infections (PEIs) are one of the most frequent clinical lesions in the oral cavity, resulting in apical periodontitis and tooth damage caused by loss of minerals. The conventional root canal disinfectants are poorly bio-safe and harmful to teeth and tissues, making them ineffective in treating PEIs. The development of nanomaterials is emerging as a promising strategy to eradicate disease-related bacteria/fungi. Herein, glucose oxidase (GOx)-modified magnetic nanoparticles (MNPs) were synthesized via a facile and versatile route for investigating their effects on removing PEI-related bacterial/fungal biofilms. It is found that GOx was successfully immobilized on the MNPs by detecting the changes in the diameter, chemical functional group, charge, and magnetic response. Further, we demonstrate that GOx-modified MNPs (GMNPs) exhibit highly effective antibacterial activity against Enterococcus faecalis and Candida albicans. Moreover, the antibacterial/fungal activity of GMNPs is greatly dependent on their concentrations. Importantly, when placed in contact with bacterial/fungal biofilms, the dense biofilm matrix is destructed due to the movement of GMNPs induced by the magnetic field, the formation of reactive oxygen species, and nutrient starvation induced by GOx. Also, the in vitro experiment shows that the as-prepared GMNPs have excellent cytocompatibility and blood compatibility. Thus, GMNPs offer a novel strategy to treat bacteria/fungi-associated PEIs for potential clinical applications.