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Research with nanoparticles for the treatment and prevention of dental caries is of special interest given the high prevalence of the disease worldwide. Several studies support the use of nanoparticles associated with materials given their antimicrobial properties and potential demineralization reduction. This study aimed to evaluate the impact of the application of silver nanoparticles (AgNPs) and chitosan gel in combination with commercial fluoride varnish on the remineralization of dental enamel. Ninety-six tooth blocks were macroscopically evaluated via stereomicroscopy, ICDAS II, and laser fluorescence. Enamel blocks were subjected to artificial demineralization and divided into four exposure groups (24, 48, 120, and 168 h), and five different remineralizing agents were applied, namely, FV (fluoride varnish), FV + CG (fluoride varnish + chitosan gel), FV + AgNPs (fluoride varnish + AgNPs), FV + AgNPs + CG (fluoride varnish + AgNPs + chitosan gel), and AgNPs + CG (AgNPs + chitosan gel). Enamel surface changes were evaluated via laser fluorescence, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Laser fluorescence results obtained from demineralized blocks and subsequently exposed to remineralizing treatment indicate significant differences. After exposure to remineralizing agents, hydroxyapatite and modified apatite phases were identified mainly in the samples treated with FV + AgNPs + CG in the groups exposed for 24, 48, and 120 h. The FV + AgNPs + CG and AgNPs + CG indicate good performance in terms of the Ca/P ratio in in vitro demineralization compared to the group treated with fluorine varnish. [ABSTRACT FROM AUTHOR]

This study evaluated push-out bond test (POBT), surface roughness, and antimicrobial properties against Enterococcus faecalis of bioceramic sealers supplemented with silver nanoparticles (AgNPs). The sealers tested were CeraSeal®, EndoSequence® BC SealerTM, and Bio-C® Sealer. The POBT was measured with a Universal Testing Machine, and the type of failure was evaluated with a stereomicroscope. The roughness average (Sa) and peak–valley height (Sy) values were evaluated by atomic force microscopy. The bacterial growth inhibition was evaluated using a disk diffusion test, and antimicrobial activity was determined with the plate microdilution method. The POBT showed no significant difference between sealers with and those without NPs in cervical and apical thirds (p > 0.05). In the middle third, the adhesion force was significant for Endosequence BC Sealer® (p < 0.05). The results showed that the Sa and Sy parameters, when AgNPs were added, did not show a statistically significant difference compared to the groups without nanoparticles (p > 0.05). All tested sealers showed bacterial growth inhibition, but no significant difference was found. Their efficacy, in descending order of antibacterial activity when AgNPs were added, is as follows: EndoSequence® BC SealerTM > Bio-C® Sealer > CeraSeal®. The incorporation of AgNPs into bioceramics improves antimicrobial activity without affecting mechanical properties. [ABSTRACT FROM AUTHOR]

Introduction: Nanoparticles (NPs) have been widely studied as an alternative to antibiotic use due to their antimicrobial properties at lower concentrations. Enterococcus faecalis is a facultative Gram‐positive microorganism inhabiting the gastrointestinal tract of humans and animals. It can also be present in other environments such as the oral cavity, water, sewage, soil and food. Aims: We evaluated whether E. faecalis could develop resistance to silver NPs (AgNPs) after exposure to sublethal concentrations of the NPs. Methods and Results: Proteomic analyses revealed that different pathways were activated during the acquired resistance under sublethal concentrations, and selected genes were validated by qPCR. Conclusions: The results of this study showed that E. faecalis is capable of generating resistance to AgNPs. Significance and Impact of the Study: To avoid the generation of resistance against AgNPs, future use of these NPs should be combined with other NPs prepared with different metals to prevent the dissemination of resistant strains. [ABSTRACT FROM AUTHOR]

Background and Objectives: Orthodontic tooth movement is associated with inflammatory responses. The aim of this study was to identify gingival microcirculation using laser Doppler flowmetry in patients with orthodontic treatment. Materials and Methods: A longitudinal pilot study was performed. The participants were selected using a non-probability consecutive sampling. Of the twenty-five subjects, a total of six (four women and two men) complied with the criteria. Before and during the treatment, the oral hygiene index, gingival index, probing depth, level of epithelial attachment, and gingival microcirculation were evaluated with laser Doppler flowmetry (integrated parameters: 1. integrated primary basal flow (IPBF), 2. integrated total secondary real flow (ITSRF), and 3. difference between integration (DBI)) in all of the participants). Results: (a) An increase in gingival blood flow was identified at all time intervals with different arches during orthodontic treatment. (b) The IPBF and ITSRF (with treatment) identified after 20 min (treatment initial stage) were compared with the different time intervals, and we observed an increase in gingival perfusion at the 24th, 48th, and 72nd hours in some arches. (c) In the DBI, we found statistically significant differences (p < 0.005) in the Nitinol group of 0.016 inches among all the time intervals (24 h, 48 h, and 72 h) within the 30-day interval, observing a flow increase three times greater than the basal flow after 30 days. Conclusions: Healthcare professionals must identify the inflammatory processes in treatment to observe and discontinue use of harmful methods in clinical practice. [ABSTRACT FROM AUTHOR]

Biofilms are matrices synthesized by bacteria containing polysaccharides, DNA, and proteins. The development of biofilms in infectious processes can induce a chronic inflammatory response that may progress to the destruction of tissues. The treatment of biofilms is difficult because they serve as a bacterial mechanism of defense and high doses of antibiotics are necessary to treat these infections with limited positive results. It has been demonstrated that photothermal therapy using gold nanorods (AuNRs) is an attractive treatment because of its anti‐biofilm activity. The purpose of this work was to generate a novel chitosan‐based hydrogel embedded with AuNRs to evaluate its anti‐biofilm activity. AuNRs were synthesized by the seed‐mediated growth method and mixed with the chitosan‐based hydrogel. Hydrogels were characterized and tested against two bacterial strains by irradiating the produced biofilm in the presence of the nanoformulation with a laser adjusted at the near infrared spectrum. In addition, the safety of the nanoformulation was assessed with normal human gingival fibroblasts. Results showed that a significant bacterial killing was measured when biofilms were exposed to an increase of 10°C for a short time of 2 min. Moreover, no cytotoxicity was measured when normal gingival fibroblasts were exposed to the nanoformulation using the bactericidal conditions. The development of the reported formulation can be used as a direct application to treat periodontal diseases or biofilm‐produced bacteria that colonize the oral cavity. [ABSTRACT FROM AUTHOR]

Background:  In large-scale molecular studies, a protocol that generates high yields and quality DNA for future polymerase chain reaction (PCR) assays is needed. The collection of buccal cells by cytobrush may represent an efficient, noninvasive, and inexpensive method for obtaining genetic material from school populations. The aim of this study was to develop a method to obtain genomic DNA from buccal cells of schoolchildren, and the DNA was extracted immediately after collecting the buccal cell samples and after storing the samples for 8 months at -20 °C to establish the feasibility of the method for epidemiological studies., Methods:  Forty-five Salvadoran schoolchildren aged between seven and fifteen years participated. Two samples of buccal cells were collected with cytobrush from each subject. The yield of the extracted DNA was evaluated by spectrophotometry, and purity was measured using optical density (OD) 260/280. The functional quality was assessed by PCR and established by amplifying the 536 bp region of the β-hCG gene., Results:  The yield was 65.70 μg for the immediate extraction group and 47.63 μg for the extraction group after eight months of storage at -20°C. The purity measured was 2.0 for immediate extraction and 1.9 for extraction after eight months. The functional quality was greater than 90% for both groups., Conclusion:  This protocol can be used to obtain DNA of high yield, purity, and functional quality from schoolchildren for genetic epidemiological studies based on PCR. This method is effective whether DNA is extracted immediately after collection or after buccal cell samples have been stored at 20°C for eight months., Competing Interests: Human subjects: Consent for treatment and open access publication was obtained or waived by all participants in this study. Ethics Committee of the Faculty of Dentistry of the University of El Salvador issued approval CEI-FOUES-2022-012. We declare that this research has been approved by the Ethics Committee of the Faculty of Dentistry of the University of El Salvador, according to the resolution CEI-FOUES-2022-012. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Escobar de González et al.)