OBJECTIVES:Restoring the original composition and properties of damaged tissues is aimed by regenerative medicine. The objective of the study was to assess remineralization and bonding capabilities of etched dentin treated with polymeric nanoparticles (NPs) functionalized with parathyroid hormone related proteins (PTHrP). METHODS:Dentin etched surfaces were treated with NPs and PTHrP-NPs. The created bonded interfaces were stored for 24 h and further submitted to thermal, chemical and mechanical challenging. Interfaces were assessed through microtensile bond strength, nanohardness, Raman analysis, a fluorescent technique with a confocal laser scanning microscopy, and scanning electron microscopy. RESULTS:Surfaces of dentin treated with PTHrP-NPs and load cycling or immersed in collagenase showed higher bond strength than the other groups. PTHrP promoted the highest nanohardness and phosphate peak intensity at the interface when load cycling was applied. Both porosity and nanoleakage were declined after PTHrP-NPs infiltration. Dentinal tubule walls and hybrid layer showed the strongest signals of xylenol orange stain. CONCLUSIONS:The highest dentin bonding efficacy was obtained in samples treated with PTHrP-NPs, as they inducted the greatest remineralization measured by nanoindentation and Raman analysis, high values of bond strength and advanced mineral deposition at the resin-dentin interface and tubules. PTHrP-NPs enabled sealing with scarce nanoleakage and porosity at the interface. SIGNIFICANCE:Etched dentin infiltration with hydrophilic polymeric NPs functionalized with parathyroid hormone related proteins, poses an advance in regenerative dentistry, by developing therapeutic bioactivity.

OBJECTIVES:The aim of this study was to examine the efficacy of self-assembling peptides in promoting remineralization on demineralized dentin surfaces. DATA, SOURCES AND STUDY SELECTION:A comprehensive electronic search was conducted using the MEDLINE via PubMed, EMBASE, Web of Science (WOS), and Scopus databases. The inclusion criteria focused on in vitro investigations using demineralized dentin surfaces from extracted permanent human teeth. These studies applied self-assembling peptides and evaluated tissue remineralization or mechanical properties. A total of 13 manuscripts met the inclusion criteria. The PRISMA guidelines were followed, and the methodological quality and risk of bias were evaluated according to the RoBDEMAT guidelines. Additionally, tables were created for data extraction, comprising outcomes related to dentin remineralization and mechanical properties assessment. CONCLUSIONS:Self-assembling peptides, particularly P11-4, have demonstrated the potential to promote remineralization and enhance the mechanical properties of demineralized dentin surfaces. Self-assembling peptides appear to be a promising approach for achieving intrafibrillar remineralization. CLINICAL SIGNIFICANCE:Dentin remineralization is one of the characteristics that biomaterials used in adhesive dentistry should aim for, as it can prolong the lifespan of restorations. Self-assembling peptides have shown potential to remineralize dentin surfaces.

OBJECTIVE:To evaluate the effect of zinc-doped polymeric nanoparticles application on pain reduction in dentin hypersensitivity (DH). METHODS:This study was a parallel, double-blind, placebo-controlled, single-center randomized clinical trial. Sixty patients with DH were enrolled in the study. Zinc-doped polymeric nanoparticles (NPs) (test group n = 30) and placebo solution (control group n = 30) were applied. Visual analogue scale (VAS) by both air blast and percussion tests, and the Schiff air index were used to follow up the symptoms of DH. Patients were recalled 7 times throughout 21 days for sensitivity screening. Results were analyzed by a mixed ANOVA and Bonferroni corrected pair-wise comparisons (p ≤ 0.05). RESULTS:VAS after air-blast and Schiff sensitivity scores attained significant differences when the NPs were applied if compared to the control group, at any time point. VAS after percussion showed significant differences immediately after treatment and at day 14 after NPs application. CONCLUSIONS:After the 21 days follow-up, VAS after air-blast and Schiff air index scores measured in patients affected with dentin hypersensitivity had a progressive significant reduction in sensitivity after nanoparticles application, and completely disappeared at 21 d time point. Dental percussion was scarcely predictable, as VAS hypersensitivity only marked significant differences between groups initially and at the 14th of the study. SIGNIFICANCE:Zn-doped NPs application on cervical dentin has contributed to the total disappearance of sensitivity after 21 d follow-up, measured as VAS after air-blast and Schiff air index scores. Therefore, the present NPs may be proposed as an effective dentin desensitizer.

ABSTRACT Aim To study the differential presence of amyloid‐β and bacterial lipopolysaccharide (LPS) in freshly extracted titanium implants, either affected by peri‐implantitis (PI) or explanted by other causes, and to address a method for removal LPS and amyloid‐β from contaminated surfaces. Methods Twenty‐four explanted implants were harvested from patients with ( n = 12) or without ( n = 12) peri‐implantitis, and their surfaces were analyzed by attenuated total reflectance (ATR) and Fourier transform infrared spectroscopy (FTIR) to localize amyloid‐β and LPS. Presence of amyloid‐β on the implants surfaces was further analyzed by light microscopy after specific amyloid staining with Congo red. Titanium discs were contaminated with LPS and amyloid‐β, these discs as well as six contaminated implants were treated with 0.25% NaOCl to assess its decontamination ability. Results LPS and amyloid‐β were observed at PI affected implant surfaces, but not in implants extracted by other causes. 0.25% NaOCl application was an efficient method for removing LPS and amyloid‐β from titanium surfaces. Conclusions The concurrent presence of LPS and amyloid‐β on the surface of implants affected by PI was demonstrated and it may act as potential comediators of PI inflammatory process. Eliminating these products from implants surfaces is possible after a proteolytic agent (0.25% NaOCl) application.

Collagen-based membrane is the most commonly used biomaterial for guided bone and tissue regeneration; however, its barrier function can be threatened by its rapid degradation pattern, affecting the success of the regeneration process. Differences in the origin and functionalization of the membrane to obtain better properties can alter the degradation rate. The objective of this study was to examine the biodegradation pattern of two commercially available collagen membranes (Jason® and Collprotect®) manufactured using porcine pericardium or dermis, doped or not with zinc-ions or doxycycline, in a period up to 21 days. The membrane specimens were subjected to hydrolytic and bacterial degradation tests. The different immersion times were carried out from 12 h up to 21 days. At each time point, quantitative measurements of thickness and weight were made using a digital caliper and an analytic microbalance, respectively. ANOVA and Student–Newman–Keuls tests were carried out for comparison purposes (p < 0.05). The differences between time-points within the same membranes and solutions were assessed by pairwise comparisons (p < 0.001). Unfunctionalized Jason membrane made of porcine pericardium attained the highest resistance to both degradation tests. The functionalization of the membranes did not alter the biodegradation patterns. All the membranes completely degraded before 48 h in the bacterial collagenase solution, which was the most aggressive test.

Objectives Tideglusib (Tx) is known for its osteogenic potential, yet its effects on the interplay between osteoblasts and M1 macrophages remain underexplored. This in vitro study aimed to isolate and evaluate both the individual and combined roles of M1 macrophages and osteoblasts in macrophage differentiation and osteoblast function, specifically focusing on how these interactions influence protein expression of osteogenesis and osteoclastogenesis in the presence or absence of Tx. Methods Osteoblast and macrophage cells were co-cultured in direct contact for 24 and 48 h, with or without the presence of Tx. ALP activity, the expression of inflammatory-related genes using RT-qPCR, and histological analyses were performed. Results Co-culturing osteoblasts and M1 macrophages with Tx increased alkaline phosphatase production, indicative of enhanced osteoblast activity. Histological assessments revealed that Tx treatment contributed to the stability and maintenance of cell morphology within the scaffold, suggesting a supportive environment for cell viability and function. Tx significantly reduced the expression of pro-inflammatory markers, such as TNF-α and IL-1β, in the co-culture at both 24 and 48 h. Tx also effectively inhibited osteoclastogenic differentiation in macrophages, thereby diminishing their pro-inflammatory phenotype. Conclusions Tx increased ALP activity and produced a significant up-regulation of RANKL expression, indicating enhanced osteoblast differentiation and osteoclast activation. Tx mitigates macrophage-driven inflammation. Clinical significance Tx may enhance bone regeneration by modulating inflammatory responses and preserving cell integrity.

ObjectiveTo evaluate whether nanoparticles (NPs) functionalized with Tideglusib (TDg, NP-12), and deposited on titanium surfaces, would counteract the effect of bacterial lipopolysaccharide (LPS) on osteoblasts.MethodsExperimental groups were: (a) Titanium discs (TiD), (b) TiD covered with undoped NPs (Un-NPs) and (c) TiD covered with TDg-doped NPs (TDg-NPs). Human primary osteoblasts were cultured onto these discs, in the presence or absence of bacterial LPS. Cell proliferation was assessed by MTT-assay and differentiation by measuring the alkaline phosphatase activity. Mineral nodule formation was assessed by the alizarin red test. Real-time quantitative polymerase chain reaction was used to study the expression of Runx-2, OSX, ALP, OSC, OPG, RANKL, Col-I, BMP-2, BMP-7, TGF-β1, VEGF, TGF-βR1, TGF-βR2, and TGF-βR3 genes. Osteoblasts morphology was studied by Scanning Electron Microscopy. One-way ANOVA or Kruskal-Wallis and Bonferroni multiple comparisons tests were carried out (p < 0.05).ResultsTDg-NPs enhanced osteoblasts proliferation. Similarly, this group increased ALP production and mineral nodules formation. TDg-NPs on titanium discs resulted in overexpression of the proliferative genes, OSC and OSX, regardless of LPS activity. In the absence of LPS, TDg-NPs up-regulated Runx2, COL-I, ALP, BMP2 and BMP7 genes. OPG/RANKL gene ratios were increased about 2500 and 4,000-fold by TDg-NPs, when LPS was added or not, respectively. In contact with the TDg-NPs osteoblasts demonstrated an elongated spindle-shaped morphology with extracellular matrix production.SignificanceTDg-NPs on titanium discs counteracted the detrimental effect of LPS by preventing the decrease on osteoblasts proliferation and mineralization, and produced an overexpression of proliferative and bone-promoting genes on human primary osteoblasts.

ObjectivesThis study targets to assess the remineralization capability of conditioned dentin infiltrated with polymeric nanoparticles (NPs) doped with tideglusib (TDg) (TDg-NPs).MethodsDentin conditioned surfaces were infiltrated with NPs and TDg-NPs. Bonded interfaces were created, stored for 24 h and submitted to mechanical and thermal challenging. Resin-dentin interfaces were evaluated through nanohardness, Masson's trichrome staining microscopy, and Raman analysis.ResultsDentin surfaces treated with TDg-NPs and load cycled produced higher nanohardness than the rest of the groups at the hybrid layer. At the bottom of the hybrid layer, all samples treated with TDg-NPs showed higher nanohardness than the rest of the groups. Active remineralization underneath the hybrid layer was detected in all groups after TDg application and load cycling, inducting new dentinal tubuli formation. After thermocycling, remineralization at the hybrid layer was not evidenced in the absence of NPs. Raman analysis showed increase mineralization, enriched carbonate apatite formation, and improved crosslinking and scaffolding of the collagen.ConclusionsMechanical loading on the specimens obtained after TDg-NPs dentin infiltration inducts an increase of mineralization at the resin/dentin interface, indicating remineralization of peritubular and intertubular dentin with augmented crystallographic maturity in crystals. Enriched collagen quality was produced, generating an adequate matrix organization to promote apatite nucleation, after tideglusib infiltration.Clinical significanceAt the present research, it has been proved the creation of reparative dentin, at the resin-dentin interface, after tideglusib dentin infiltration. Chemical stability, to favor integrity of the resin-dentin interface, is warranted in the presence of the TDg-NPs in the demineralized dentin collagen.

Objective Drug-loaded non-resorbable polymeric nanoparticles (NPs) are proposed as an adjunctive treatment for pulp regenerative strategies. The present in vitro investigation aimed to evaluate the effectiveness of tideglusib-doped nanoparticles (TDg-NPs) in mitigating the adverse effects of bacterial lipopolysaccharide endotoxin (LPS) on the viability, morphology, migration, differentiation and mineralization potential of human dental pulp stem cells (hDPSCs). Methods Cell viability, proliferation, and differentiation were assessed using a MTT assay, cell migration evaluation, cell cytoskeleton staining analysis, Alizarin Red S staining and expression of the odontogenic related genes by a real-time quantitative polymerase chain reaction (RT-qPCR) were also performed. Cells were tested both with and without stimulation with LPS at various time points. One-way ANOVA and Tukey's test were employed for statistical analysis (p < 0.05). Results Adequate cell viability was encountered in all groups and at every tested time point (24, 48, 72 and 168 h), without differences among the groups (p > 0.05). The analysis of cell cytoskeleton showed nuclear alteration in cultures with undoped NPs after LPS stimulation. These cells exhibited an in blue diffuse and multifocal appearance. Some nuclei looked fragmented and condensed. hDPSCs after LPS stimulation but in the presence of TDg-NPs exhibited less nuclei changes. LPS induced down-regulation of Alkaline phosphatase, Osteonectin and Collagen1 gene markers, after 21d. LPS half-reduced the cells production of calcium deposits in all groups (p < 0.05), except in the group with TDg-NPs (decrease about 10 %). Significance LPS induced lower mineral deposition and cytoskeletal disorganization in hDPSCs. These effects were counteracted by TDg-NPs, enhancing osteogenic differentiation and mineralization.

Background'Periodontitis' refers to periodontal destruction of connective tissue attachment and bone, in response to microorganisms forming subgingival biofilms on the root surface, while 'apical periodontitis' refers to periapical inflammatory processes occurring in response to microorganisms within the root canal system. The treatment of both diseases is based on the elimination of the bacterial challenge, though its predictability depends on the ability of disrupting these biofilms, what may need adjunctive antibacterial strategies, such as the next-generation antibacterial strategies (NGAS). From all the newly developed NGAS, the use of polymeric nanotechnology may pose a potential effective approach. Although some of these strategies have only been tested in vitro and in preclinical in vivo models, their use holds a great potential, and therefore, it is relevant to understand their mechanism of action and evaluate their scientific evidence of efficacy.ObjectivesTo explore NGAS based on polymeric nanotechnology used for the potential treatment of periodontitis and apical periodontitis.MethodA systemic search of scientific publications of adjunctive antimicrobial strategies using nanopolymers to treat periodontal and periapical diseases was conducted using The National Library of Medicine (MEDLINE by PubMed), The Cochrane Oral Health Group Trials Register, EMBASE and Web of Science.ResultsDifferent polymeric nanoparticles, nanofibres and nanostructured hydrogels combined with antimicrobial substances have been identified in the periodontal literature, being the most commonly used nanopolymers of polycaprolactone, poly(lactic-co-glycolic acid) and chitosan. As antimicrobials, the most frequently used have been antibiotics, though other antimicrobial substances, such as metallic ions, peptides and naturally derived products, have also been added to the nanopolymers.ConclusionPolymeric nanomaterials containing antimicrobial compounds may be considered as a potential NGAS. Its relative efficacy, however, is not well understood since most of the existing evidence is derived from in vitro or preclinical in vivo studies.

Objectives: Tideglusib has shown great performance in terms of dentin regenerative properties. This study aims to evaluate bonding ability, of demineralized dentin infiltrated with polymeric nanoparticles (NPs) doped with tideglusib (TG) (TG-NPs). Methods: Dentin conditioned surfaces were infiltrated with NPs and TG-NPs. Bonded interfaces were created and stored for 24 h and then submitted to mechanical, chemical and thermal challenging. The resin-dentin interface was evaluated through a doubled dye fluorescent technique and a calcium chelator fluorophore under a confocal laser scanning microscopy, and by field emission scanning electron microscopy. Results: Dentin surfaces treated with TG-NPs and load cycled produced higher bond strength than the rest of the groups. Immersion of dentin specimens treated with undoped-NPs in collagenase solution attained the lowest microtensile bond strength (MTBS) values. Both porosity and nanoleakage decreased when dentin was infiltrated with TG-NPs, that revealed strong signals of xylenol orange stain at both hybrid layer and dentinal tubules. The presence of NPs, in general, inducted the presence of mineralized interfaces after mechanical loading and thermocycling. Conclusions: Nanoparticles doped with tideglusib promoted the highest dentin bonding efficacy among groups, as they facilitated the maximum bond strength values with creation of mineral deposits at the hybrid layer and dentinal walls. Tideglusib enabled scarce porosity, nanoleakage and advanced sealing among dentin groups. Significance: Doping hydrophilic polymeric NPs with tideglusib, infiltrated in etched dentin represents a reproducible technique to create reparative dentin at the resin-dentin interface, by inducing therapeutic bioactivity.

Objectives The aim of this study was to determine the viscoelastic performance and energy dissipation of conditioned dentin infiltrated with polymeric nanoparticles (NPs) doped with tideglusib (TDg) (TDg-NPs). Methods Dentin conditioned surfaces were infiltrated with NPs and TDg-NPs. Bonded interfaces were created, stored for 24 h and submitted to mechanical and thermal challenging. Resin-dentin interfaces were evaluated through nano-DMA/complex-loss-storage moduli-tan delta assessment and atomic force microscopy (AFM) analysis. Results Dentin infiltrated with NPs and load cycled attained the highest complex modulus at hybrid layer and bottom of hybrid layer. Intertubular dentin treated with undoped NPs showed higher complex modulus than peritubular dentin, after load cycling, provoking energy concentration and breakdown at the interface. After infiltrating with TDg-NPs, complex modulus was similar between peri-intertubular dentin and energy dissipated homogeneously. Tan delta at intertubular dentin was higher than at peritubular dentin, after using TDg-NPs and load cycling. This generated the widest bandwidth of the collagen fibrils and bridge-like mineral structures that, as sight of energy dissipation, fastened active dentin remodeling. TDg-NPs inducted scarce mineralization after thermo-cycling, but these bridging processes limited breakdown zones at the interface. Significance TDg-based NPs are then proposed for effective dentin remineralization and tubular seal, from a viscoelastic approach.

Objective: The aim of this study was to determine the effect of titanium micro particles (TiP) previously functionalized with nanoparticles doped with dexamethasone (Dex) and doxycycline (Dox), on macrophage polarization and activity. Methods: Macrophages RAW264.7 were cultured in the presence TiP loaded with dexamethasone -NPs (Dex)- and doxycycline -NPs (Dox)-, and as control, TiP with or without doped NPs. Cells were tested with and without previous bacterial lipopolysaccharide endotoxin (LPS) stimulation. Their morphology, proliferation, cytotoxicity, phenotypic change, and cytokines release were assessed by LIVE/DEAD, DNA release, metabolic activity, brightfield and scanning electron microscopy. The test Kruskall-Wallis was used for comparisons, while the cytokine expression profiles were examined by hierarchical clustering (p < 0.05). Results: Upon exposure with TiP macrophages were activated and polarized to M1, but without depicting cytotoxic effects. The particles were phagocytised, and vacuolized. When exposed to functionalised TiP with NPs(Dex) and NPs(Dox), the ratio M1/M2 was up to forty times lower compared to TiP alone. When exposed to LPS, TiP reduced cell viability in half. Functionalised TiP with NPs(Dex) inhibited the cytokine release exerted by TiP on macrophages. When macrophages were exposed to functionalised TiPs with NPs(Dex) with and without LPS, the effect of TiP on cytokine secretion was inhibited. Significance: Functionalised TiPs with NPs(Dex) and NPs(Dox) may potentially have beneficial effects on modulating titanium and LPS-related inflammatory reactions.

Objectives The aim of this systematic review was to demonstrate the efficacy of topical application of corticosteroids in remineralization of dental pulp tissues to preserve their vitality and function. Data, Sources and Study Selection An electronic search was performed using MEDLINE by PubMed, EMBASE, Web of Science (WOS), and Scopus databases. The inclusion criteria were in vitro studies that employed dental pulp tissue obtained from extracted healthy permanent human teeth and were subjected to topical administration of corticosteroids and evaluated tissue remineralization by performing any mineralization assay. A total of 11 studies were selected for inclusion. PRISMA guidelines were followed, and the methodological quality and risk of bias of the included studies were evaluated using the RoBDEMAT guidelines. Also, tables were designed for data extraction, including tissue mineralization and osteogenic differentiation as primary and secondary outcomes, respectively. Conclusions Alizarin Red S (ARS) has been able to demonstrate a possible mineralizing power of corticosteroids, applied at an adequate dose. The up-regulation of Alkaline phosphatase (ALP), osteocalcin (OCN), osteopontin (OSP), sialophosphoprotein (DSPP), runt-related transcription factor 2 (RUNX2), collagen type 1 alpha 1(COL1α1) and dentin matrix protein 1 (DMP-1) induced the osteogenic/odontogenic differentiation of dental pulp stem cells (DPSCs). Clinical Significance Deep carious lesions treatment is still challenging in restorative dentistry. Some treatments have been focused on dental pulp tissue remineralization to maintain the function and vitality. After corticosteroids topical application, mineral deposition and osteogenic differentiation have been detected.

Objectives To investigate the effect of dentin infiltration with polymeric nanoparticles (NPs) doped with tideglusib (TDg) (TDg-NPs) on hydroxyapatite formation, crystallinity and elasticity of conditioned resin-dentin interfaces. Methods Dentin conditioned surfaces were infiltrated with NPs or TDg-NPs. Bonded interfaces were created, stored for 24 h and submitted to mechanical and thermal challenging. Resin-dentin interfaces were evaluated through nanoindentation to determine the modulus of elasticity, X-ray diffraction and transmission electron microscopy through selected area diffraction and bright-filed imaging. Results TDg-NPs provoked peaks narrowing after the diffraction-intensity analysis that corresponded with high crystallinity, with an increased modulus of Young after load cycling in comparison with the samples treated with undoped NPs. New minerals, in the group of TDg-NPs, showed the greatest both deviation of line profile from perfect crystal diffraction and dimension of the lattice strain, i.e, crystallite, grain size and microstrain and 002 plane-texture. The new minerals generated after TDg-NPs application and mechanical loading followed a well defined lineation. Undoped NPs mostly produced small hydroxyapatite crystallites, non crystalline or amorphous in nature with poor maturity. Conclusions Tideglusib promoted the precipitation of hydroxyapatite, as a major crystalline phase, at the intrafibrillar compartment of the collagen fibrils, enabling functional mineralization. TDg-NPs facilitated nucleation of crystals randomly oriented, showing less structural variation in angles and distances that improved crystallographic relative order of atoms and maturity. Nanocrystals inducted by TDg-NPs were hexagonal prisms of submicron size. Thermal challenging of dentin treated with TDg-NPs have provoked a decrease of functional mineralization and crystallinity, associated to immature hydroxyapatite. Clinical significance New polycrystalline lattice formation generated after TDg-NPs infiltration may become correlated with high mechanical performance. This association can be inferred from the superior crystallinity that was obtained in presence of tideglusib. Immature crystallites formed in dentin treated with undoped NPs will account for a high remineralizing activity.

In periodontitis, the bone remodeling process is disrupted by the prevalent involvement of bacteria-induced proinflammatory macrophage cells and their interaction with osteoblast cells residing within the infected bone tissue. The complex interaction between the cells needs to be deciphered to understand the dominant player in tipping the balance from osteogenesis to osteoclastogenesis. Yet, only a few studies have examined the crosstalk interaction between osteoblasts and macrophages using biomimetic three-dimensional (3D) tissue-like matrices. In this study, we created a cell-laden 3D tissue analog to study indirect crosstalk between these two cell types and their direct synergistic effect when cultured on a 3D scaffold. The cell-specific role of osteoclast differentiation was investigated through osteoblast-and proinflammatory macrophage-specific feedback studies. The results suggested that when macrophages were exposed to osteoblasts-derived conditioned media from the mineralized matrix, the M1 macrophages tended to maintain their proinflammatory phenotype.Further, when osteoblasts were exposed to secretions from proinflammatory macrophages, they demonstrated elevated receptor activator of nuclear factor-kB ligand (RANKL) expression and decreased alkaline phosphate (ALP) activities compared to osteoblasts exposed to only osteogenic media. In addition, the upregulation of tumor necrosis factor-alpha (TNF-a) and c-Fos in proinflammatory macrophages within the 3D matrix indirectly increased the RANKL expression and reduced the ALP activity of osteoblasts, promoting osteoclastogenesis. The contact coculturing with osteoblast and proinflammatory macrophages within the 3D matrix demonstrated that the proinflammatory markers (TNF-a and interleukin-1b) expressions were upregulated. In contrast, anti-inflammatory markers (c-c motif chemokine ligand 18 [CCL18]) were downregulated, and osteoclastogenic markers (TNF receptor associated factor 6 [TRAF6] and acid phosphatase 5, tartrate resistant [ACP5]) were unchanged. The data suggested that the osteoblasts curbed the osteoclastogenic differentiation of macrophages while macrophages still preserved their proinflammatory lineages. The osteoblast within the 3D coculture demonstrated increased ALP activity and did not express RANKL significantly different than the osteoblast cultured within a 3D collagen matrix without macrophages. Contact coculturing has an anabolic effect on bone tissue in a bacteria-derived inflammatory environment.

Objective: To investigate the effect of novel polymeric nanoparticles (NPs) doped with dexamethasone (Dex) on viscoelasticity, crystallinity and ultra-nanostructure of the formed hydroxyapatite after NPs dentin infiltration.Methods: Undoped-NPs, Dex-doped NPs (Dex-NPs) and zinc-doped-Dex-NPs (Zn-Dex-NPs) were tested at dentin, after 24 h and 21 d. A control group without NPs was included. Coronal dentin surfaces were studied by nano-dynamic mechanical analysis measure-ments, atomic force microscopy, X-ray diffraction and transmission electron microscopy. Mean and standard deviation were analyzed by ANOVA and Student-Newman-Keuls multiple comparisons (p < 0.05). Results: At 21 d of storage time, both groups doped with Dex exhibited the highest com-plex, storage and loss moduli among groups. Zn-Dex-NPs and Dex-NPs promoted the highest and lowest tan delta values, respectively. Dex-NPs contributed to increase the fibril diameters of dentin collagen over time. Dentin surfaces treated with Zn-Dex-NPs attained the lowest nano-roughness values, provoked the highest crystallinity, and produced the longest and shortest crystallite and grain size. These new crystals organized with ran-domly oriented lattices. Dex-NPs induced the highest microstrain. Crystalline and amor-phous matter was present in the mineral precipitates of all groups, but Zn and Dex loaded NPs helped to increase crystallinity.Significance: Dentin treated with Zn-Dex-NPs improved crystallographic and atomic order, providing structural stability, high mechanical performance and tissue maturation. Amorphous content was also present, so high hydroxyapatite solubility, bioactivity and remineralizing activity due to the high ion-rich environment took place in the infiltrated dentin.(c) 2022 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

To evaluate the in vitro biocompatibility of dexamethasone-doped polymeric nanoparticles (Dex-NPs) to be employed as immunomodulator agent aiding in the treatment of peri-implantitis. Polymeric nanoparticles (NPs) were obtained through a polymerization precipitation technique. The NPs are composed of 2-hydroxyethyl methacrylate as the backbone monomer, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate acting as a cross-linker. NPs were doped with dexamethasone (Dex) through immersion in a Dex aqueous solution for 2 h, at room temperature and under constant shaking, in order to reach the Dex adsorption equilibrium. Subsequently, the suspensions were centrifuged and the particles were detached from the supernatant. Different eluates of NPs were prepared at concentrations (0.1,1,10 and 100 µg•mL-1). Undoped nanoparticles were also included in the study. Bone marrow mesenchymal stromal cells (BMMSC) were cultured. The cell cytotoxicity and viability was assessed by analyzing the resazurin-based assays after 24, 48, 72 and 168 h of culture, light absorbance per well was recorded by means of a microplate reader. Phalloidin staining was used to analyze changes in cell morphology and in the actin cytoskeleton structure and organization. Cell cycle analysis was performed by flow cytometry to evaluate cells viability after exposure to the different NPs. Statistical differences were assessed by ANOVA and Tukey's test (p<0.05). Cytotoxicity was only produced on cells cultured in the presence of Dex-NPs and undoped NPs when using concentrations of 10 or 100 µg•mL-1, after 7d (Graphic 1). Phalloidin staining demonstrated cells' structural integrity, except when NPs were used at 100 µg•mL-1. In this case nuclei alterations were evidenced. After cells' cycle analysis, none of the NPs used disturbed the cell cycle, there being a similar percentage of cells in each of the stages of the cell cycle; except for NPs at 100 µg•mL-1, it was shown that cell division was interrupted and cells remained at DNA synthesis stage (Figure 1). Favorable in vitro cytocompatibility has been demonstrated when NPs were used at 0.1 and 1 µg•mL-1. Biological activity of doped NPs at these concentrations has to be demonstrated in order to facilitate the clinical use of this new therapeutic tool. Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (FEDER), grants numbers [PID2020-114694RB-I00 and PID2020-115887GB-I00 MINECO/AEI/FEDER/UE]. M. Toledano-Osorio holds a FPU fellowship from the Ministry of Universities [FPU20/00450].Download : Download high-res image (201KB)Download : Download full-size image