Development of antibacterial composite resin containing chitosan/fluoride microparticles as pit and fissure sealant to prevent caries

Novel pit and fissure sealant with nano-CaF2 and antibacterial monomer: Fluoride recharge, microleakage, sealing ability and cytotoxicity

Conventional resin-based sealants release minimal fluoride ions (F) and lack antibacterial activity. The objectives of this study were to: (1) develop a novel bioactive sealant containing calcium fluoride nanoparticles (nCaF2) and antibacterial dimethylaminohexadecyl methacrylate (DMAHDM), and (2) investigate mechanical performance, F recharge and re-release, microleakage, sealing ability and cytotoxicity. Helioseal F served as commercial control. The initial F release from sealant containing 20% nCaF2 was 25-fold that of Helioseal F. After ion exhaustion and recharge, the F re-release from bioactive sealant did not decrease with increasing number of recharge and re-release cycles. Elastic modulus of new bioactive sealant was 44% higher than Helioseal F. The new sealant had excellent sealing, minimal microleakage, and good cytocompatibility. Hence, the nanostructured sealant had substantial and sustained F release and antibacterial activity, good sealing ability and biocompatibility. The novel bioactive nCaF2 sealant is promising to provide long-term F ions for caries prevention.

Biological Effects of PMMA and Composite Resins on Human Gingival Fibroblasts: An In Vitro Comparative Study

The use of temporary resin for provisional restorations is a fundamental step to maintain the position of prepared teeth, to protect the pulpal vitality and the periodontal health as well as the occlusion. The present study aimed at evaluating the biological effects of two resins used in dentistry for temporary restorations, Coldpac (Yates Motloid) and ProTemp 4™ (3M ESPE ™), and their eluates, in an in vitro model of human gingival fibroblasts (hGFs). The activation of the inflammatory pathway NFκB p65/NLRP3/IL-1β induced by the self-curing resin disks was evaluated by real-time PCR, Western blotting and immunofluorescence analysis. The hGFs adhesion on resin disks was investigated by means of inverted light microscopy and scanning electron microscopy (SEM). Our results suggest that hGF cells cultured in adhesion and with eluate derived from ProTemp 4™ (3M ESPE ™) resin evidenced a downregulation in the expression of the inflammatory mediators such as NFκB p65, NLRP3 and IL-1β compared to the cells cultured with Coldpac (Yates Motloid) after 24 h and 1 week of culture. Furthermore, the cells cultured with ProTemp 4™ (3M ESPE ™) after 24 h and 1 week of culture reported a higher cell viability compared to the cells cultured with Coldpac (Yates Motloid), established by MTS cell analysis. Similar results were obtained when hGFs were placed in culture with the eluate derived from ProTemp 4™ (3M ESPE ™) resin which showed a higher cell viability compared to the cells cultured with eluate derived from Coldpac (Yates Motloid). These results highlighted the lower pro-inflammatory action and improved cell biocompatibility of ProTemp 4™ (3M ESPE ™), suggesting a better performance in terms of cells-material interaction.

Antibacterial Agents for Composite Resin Restorative Materials: Current Knowledge and Future Prospects

Resin composites became the material of choice for direct restorations in anterior and posterior teeth. Despite the revolutionary improvement in the material, restoration failure is still a major drawback due to the material's inherent negative properties, including a lack of antibacterial effects. Therefore, many attempts have been made to incorporate antibacterial agents into resin composite materials to improve their antimicrobial properties and prevent secondary caries formation. Multiple laboratory studies have been conducted using different antibacterial agents, such as quaternary ammonium compounds, methacryloyloxydodecylpyridinium bromide, magnesium oxide nanoparticles, chlorhexidine, and chitosan. This review provides a glance at the current status of these materials and the research directions needed in the future.

Evaluation of flexural strength, degree of conversion, and demineralization-prevention properties in adjacent tooth structures of an experimental fissure sealant containing nano-calcium-phosphate compounds

BACKGROUND

The present study aimed to evaluate the flexural strength, degree of conversion, and demineralization-prevention ability of an experimental fissure sealant containing nano-calcium-phosphate compounds.

METHODS

An experimental sealant was formulated using silica and nano hydroxyapatite filler particles. The control group consisted of the DENU Seal (n = 10, each group). The flexural bond strength was evaluated by UTM. DC was evaluated by FTIR. To evaluate the demineralization-prevention ability, Cl V cavities in 10 third molar teeth restored with two sealant products, followed by an acid challenge then the Vickers microhardness test was carried out.

RESULTS

The mean flexural strength in the commercial group was higher than the experimental group. However, the mean flexural modulus was not significantly different between the two groups. In the experimental group, DC was significantly higher than the commercial group. Adjacent to the interface, the decrease in microhardness in the experimental group was significantly less than the commercial group. However, on the tooth surface, there were no significant differences between the two groups. In the experimental group, the decrease in microhardness at the interface was less than at the tooth surface, however the situation was opposite in the commercial group.

CONCLUSIONS

Incorporating hydroxyapatite into the sealant structure might prevent demineralization, without adverse effects on flexural modulus and degree of conversion.

Do nanofillers provide better physicomechanical properties to resin-based pit and fissure sealants? A systematic review

The purpose of this study was to systematically review the impact of nanofillers on the physicomechanical properties of resin-based pit and fissure sealants (RBS). This review included in vitro studies with full-length English-language articles reporting on the physicomechanical properties of nanofilled RBS until February 2023. PubMed, Web of Sciences, Scopus, and LILACS databases were accessed for literature searches. The review was formulated based on the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines and used the Consolidated Standards of Reporting Trials (CONSORT) guidelines and risk of bias Cochrane tool for quality assessment. The search resulted in 539 papers, of which 22 were eligible to be included in the review. Inorganic, polymeric, core-shell, and composite nanomaterials were used to reinforce the studied RBS. The inherent nature of the nanomaterial used, its morphology, concentration, and volume used were the primary parameters that determined the nanomaterial's success as a filler in RBS. These parameters also influenced their interaction with the resin matrix, which influenced the final physicomechanical properties of RBS. The use of nanofillers that were non-agglomerated and well dispersed in the resin matrix enhanced the physicomechanical properties of RBS.

Effect of Zinc Oxide Incorporation on the Antibacterial, Physicochemical, and Mechanical Properties of Pit and Fissure Sealants

This study aimed to evaluate the antibacterial, physicochemical, and mechanical properties of pit and fissure sealants containing different weight percentages of zinc oxide nanoparticles (ZnO NPs). The following amounts of ZnO NPs were added to a commercially available pit and fissure sealant (BeautiSealant, Shofu, Japan) to prepare the experimental materials: 0 wt.% (commercial control (CC)), 0.5 wt.% (ZnO 0.5), 1 wt.% (ZnO 1.0), 2 wt.% (ZnO 2.0), and 4 wt.% (ZnO 4.0). The antibacterial effect against S. mutans was confirmed by counting the colony-forming units (CFUs) and observing live/dead bacteria. In addition, ion release, depth of cure, water sorption and solubility, and flexural strength tests were conducted. When compared with the CC, the experimental groups containing ZnO NPs showed zinc ion emission and significantly different CFUs (p < 0.05) with fewer live bacteria. ZnO NP addition reduced the depth of cure and water solubility and increased water sorption in comparison with the CC (p < 0.05). However, all groups showed similar flexural strength (p > 0.05). The pit and fissure sealants containing ZnO NPs exhibited antibacterial activity against S. mutans with no negative effects on physicochemical and mechanical properties, and thus, these sealants can be ideal secondary caries prevention material.

Chitosan-Heparin Polyelectrolyte Multilayer-Modified Poly(vinyl alcohol) Vascular Patches based on a Decellularized Scaffold for Vascular Regeneration

Vascular patches play an important role in vascular reparation and cardiovascular diseases therapy. Recently, decellularized scaffold (DCS)-based vascular patches have drawn attention for their good biocompatibility and blood compatibility. In this work, we developed a poly(vinyl alcohol)-coated DCS as a vascular patch for vascular regeneration. Polyelectrolyte multilayers (PEMs) were further decorated on the surface via layer-by-layer (LbL) self-assembly to improve the biocompatibility of the vascular patch. According to the in vitro experiment, the vascular patch exhibited rapid endothelialization and good hemocompatibility. Compared with unmodified poly(vinyl alcohol)/DCS, the PEM-modified vascular patch possesses improved hemocompatibility, for example, enhanced anti-platelet adhesion ability, prolonged in vitro coagulation time, and decreased hemolysis rate. Therefore, this vascular patch is conducive to the proliferation and attachment of endothelial progenitor cells. Meanwhile, the in vivo performance in a porcine model was investigated with the in vivo computed tomography angiography and B ultrasound was used to further confirm the vascular regeneration. Excitedly, the porcine artery could remain unblocked for 5 months after implantation. Our current research provides a potential strategy for treating diseased blood vessels in clinical surgery.