Eicosanoid profiles in an arthritis model: Effects of a soluble epoxide hydrolase inhibitor.

Rheumatoid arthritis is a common systemic inflammatory autoimmune disease characterized by damage to joints, inflammation and pain. It is driven by an increase of inflammatory cytokines and lipids mediators such as prostaglandins. Epoxides of polyunsaturated fatty acids (PUFAs) are lipid chemical mediators in a group of regulatory compounds termed eicosanoids. These epoxy fatty acids (EpFA) have resolutive functions but are rapidly metabolized by the soluble epoxide hydrolase enzyme (sEH) into the corresponding diols. The pharmacological inhibition of sEH stabilizes EpFA from hydrolysis, improving their half-lives and biological effects. These anti-inflammatory EpFA, are analgesic in neuropathic and inflammatory pain conditions. Nonetheless, inhibition of sEH on arthritis and the resulting effects on eicosanoids profiles are little explored despite the physiological importance. In this study, we investigated the effect of sEH inhibition on collagen-induced arthritis (CIA) and its impact on the plasma eicosanoid profile. We measured the eicosanoid metabolites by LC-MS/MS-based lipidomic analysis. The treatment with a sEH inhibitor significantly modulated 11 out of 69 eicosanoids, including increased epoxides 12(13)-EpODE, 12(13)-EpOME, 13-oxo-ODE, 15-HEPE, 20-COOH-LTB4 and decreases several diols 15,6-DiHODE, 12,13-DiHOME, 14,15-DiHETrE, 5,6-DiHETrE and 16,17-DiHDPE. Overall the inhibition of sEH in the rheumatoid arthritis model enhanced epoxides generally considered anti-inflammatory or resolutive mediators and decreased several diols with inflammatory features. These findings support the hypothesis that inhibiting the sEH increases systemic EpFA levels, advancing the understanding of the impact of these lipid mediators as therapeutical targets.

Sema4D is diminished in leukocyte platelet-rich fibrin and impairs pre-osteoblastic MC3T3-E1 cells' functionality.

OBJECTIVE: Semaphorin 4D (Sema4D) is a coupling factor expressed on osteoclasts that may hinder osteoblast differentiation. Since the leukocyte platelet-rich fibrin (L-PRF) membrane promotes growth factor concentration, this study aims to quantify the amount of Sema4D in L-PRF membranes, and analyze the impact of Sema4D on osteoblast cell function in vitro. DESIGN: Enzyme-linked immunosorbent assay (ELISA) was used to quantify the levels of Sema4D in both L-PRF and whole blood (serum). To analyze the impairment of Sema4D on osteoblasts, MC3T3-E1 cells were induced to osteogenic differentiation and exposed to Sema4D ranging from 10 to 500 ng/ml concentrations. The following parameters were assayed: 1) cell viability by MTT assay after 24, 48, and 72 h; 2) matrix mineralization by Alizarin Red staining after 14 days, 3) Runt-related transcription factor 2 (RUNX-2), osteocalcin (OCN), osteonectin (ONC), bone sialoprotein (BSP) and alkaline phosphatase (ALP) gene expression by qPCR. For all data, the significance level was set at 5%. RESULTS: The amount of Sema4D in the whole blood (serum) was higher than in L-PRF. Osteoblasts exposed to Sema4D at all tested concentrations exhibited a decrease in matrix mineralization formation as well in RUNX-2, OCN, ONC, BSP, and ALP gene expression (p < 0.05). CONCLUSION: The presence of Sema4D, a molecule known for suppressing osteoblast activity, diminishes within L-PRF, enhancing its ability to facilitate bone regeneration.

Experimental traumatic occlusion drives immune changes in trigeminal ganglion.

We previously demonstrated that experimental traumatic occlusion (ETO) induces a long-lasting nociceptive response. These findings were associated with altered neuronal patterns and suggestive satellite glial cell activation. This study aimed to elucidate the activation of satellite glial cells following ETO in the trigeminal ganglion. Moreover, we explored the involvement of resident and infiltrating cells in trigeminal ganglion in ETO. Finally, we investigated the overexpression of purinergic signaling and the CX3CL1/CX3CR1 axis. RT-qPCR and electrophoresis showed overexpression of GFAP in the trigeminal ganglion (TG), and immunohistochemistry corroborated these findings, demonstrating SGCs activation. ELISA reveals enhanced levels of TNF-α and IL-1ß in TG after 28 d of ETO. In trigeminal ganglia, ETO groups improved the release of CX3CL1, and immunohistochemistry showed higher CX3CR1+ -immunoreactive cells in ETO groups. Immunohistochemistry and electrophoresis of the P2X7 receptor were found in ETO groups. The mRNA levels of IBA1 are upregulated in the 0.7-mm ETO group, while immunohistochemistry showed higher IBA1+ -immunoreactive cells in both ETO groups. The expression of CD68 by electrophoresis and immunohistochemistry was observed in the ETO groups. For last, ELISA revealed increased levels of IL-6, IL-12, and CCL2 in the TG of ETO groups. Furthermore, the mRNA expression revealed augmented transcription factors and cytokines associated with lymphocyte activation, such as RORγt, IL-17, Tbet, IFNγ, FOXP3, and IL-10. The findings of this study suggested that ETO activates SGCs in TG, and purinergic signaling and CX3CL1/CX3CR1 axis were upregulated. We uncovered the involvement of a distinct subtype of macrophages, named sensory neuron-associated macrophage activation (sNMAs), and detected an expanded number of infiltrated macrophages onto TG. These findings indicate that ETO induces chronic/persistent immune response.

PI3Kγ controls IL-17A expression and attenuates alveolar bone loss in an experimental periodontitis model.

OBJECTIVE: In this study, we investigated the modulatory effects of PI3Kγ on IL-17A expression and the progression of experimental periodontitis in vivo. METHODS: Ligature-induced periodontitis was developed around the first molar of mice. Animals were treated with anti-mouse IL-17A or IPI-549 (PI3Kγ inhibitor). In addition, PI3Kγ-deficient mice (PI3Kγ-/-) were used in the study. Alveolar bone loss was measured and real-time PCR of Il17a and Rankl genes was performed. A bioinformatics analysis was carried out using the Gene Set Enrichment Analysis computational tool. RESULTS: Nine days after ligature placement, alveolar bone loss scores were significantly increased, with upregulation of Il17a and Rankl genes in the gingival tissues. Treatment with anti-mouse IL-17A (100 µg/mice) significantly attenuated alveolar bone loss. Mice with ligature-induced periodontitis treated with IPI-549 (3 mg/kg) or PI3Kγ-/- mice showed reduced alveolar bone loss and downregulation of Il17a and Rankl gene expression in the gingival tissues. Consistent with this, the bioinformatics analysis showed upregulation of IL17F, IL17A, IL17D, and STAT3 genes, as well as greater activation of IL-17 and PI3KCI pathways (upregulation of PIK3CG gene) in the gingival tissue of patients with periodontitis. CONCLUSION: PI3Kγ plays an important role in modulating IL-17A expression and alveolar bone loss in vivo and can be considered a promising pathway for the management of periodontal disease and the development of new therapies.

Lithium chloride stimulates bone formation in extraction socket repair in rats.

PURPOSE: Previous evidence shows that lithium chloride (LiCl), a suppressor of glycogen synthase kinase-3ß (GSK-3ß), may enhance bone formation in several medical and dental conditions. Thus, the purpose of the current study was to assess the effects of LiCl on extraction socket repair in rats. METHODS: Thirty rats were randomly assigned into a control group (administration of water; n = 15) or a LiCl group (administration of 150 mg/kg of LiCl; n = 15). LiCl and water were given every other day, starting at 7 days before the extraction of upper first molars until the end of each experiment period. Histological sections from five rats per group were obtained at 10, 20, and 30 days post-extractions. Histometrical analysis of newly formed bone (NB) and the levels of tartrate-resistant acid phosphatase (TRAP)-stained cells were evaluated at 10, 20, and 30 days post-extractions. Immunohistochemical staining for receptor activator of nuclear factor kappa-Β ligand (RANKL), osteoprotegerin (OPG), bone sialoprotein (BSP), osteocalcin (OCN), and osteopontin (OPN) was assessed at 10 days post-extractions. RESULTS: The LiCl group had a greater proportion of NB than the control group at 20 days (P < 0.05). At 30 days, the rate of TRAP-stained cells was lower in the LiCl group than in the control group (P < 0.05). At 10 days, the LiCl group presented stronger staining for OPG, BSP, OPN, and OCN, when compared to the control group (P < 0.05). CONCLUSION: Systemic LiCl enhanced extraction socket repair, stimulated an overall increase in bone formation markers, and restricted the levels of TRAP in rats.

Cinnamoyloxy-mammeisin, a coumarin from propolis of stingless bees, attenuates Th17 cell differentiation and autoimmune inflammation via STAT3 inhibition.

T helper 17 (Th17) lymphocytes play a critical role in the pathogenesis of autoimmune diseases, mainly by producing the pro-inflammatory cytokine interleukin-17 (IL-17). Therefore, Th17 lymphocytes have been considered a strategic target for drug discovery and development. In this study, we investigated the activity and possible mechanisms of action of a 4-phenyl coumarin isolated from propolis, named cinnamoyloxy-mammeisin (CNM), in Th17 cell differentiation and the development of experimental Th17-dependent autoimmune encephalomyelitis (EAE). Our data showed that in vitro Th17 cell differentiation was attenuated by CNM treatment in a concentration-dependent manner (1, 3, and 10 µM). This was associated with a reduction in the release of IL-17 (35% inhibition) and interleukin-22 (IL-22, 51% inhibition). Th17-differentiated cells exposed to CNM also downregulated the expression of Th17 hallmarked cell genes, such as RAR-related orphan receptor c (Rorc, 51% inhibition), and interleukin-23 receptor (Il23r, 64% inhibition), indicating possible upstream molecular mechanisms. Mechanistically, CNM significantly reduced the phosphorylation of signal transducer and activator of transcription 3 (p-STAT3) during in vitro Th17 cell differentiation. In vivo treatment with CNM (100 µg/kg) reduced the clinical signs of EAE, which was associated with a reduction in Central Nervous System demyelination, neuroinflammation, and Th17 response in the spinal cord and inguinal lymph nodes. Consistent with this, CNM also effectively attenuated human Th17 differentiation in vitro. Collectively, our results highlight the potential of CNM as a new molecule that can modulate Th17 cells via inhibition of STAT3 signaling and, as a result, reduce autoimmune inflammation.

Autologous Bone Marrow Mononuclear Cells (BMMC)-Associated Anti-Inflammatory Nanoparticles for Cardiac Repair after Myocardial Infarction.

To investigate the effect of transplantation of stem cells from the bone marrow mononuclear cells (BMMC) associated with 15d-PGJ2-loaded nanoparticles in a rat model of chronic MI. Chronic myocardial infarction (MI) was induced by the ligation of the left anterior descending artery in 40 male Wistar rats. After surgery, we transplanted bone marrow associated with 15d-PGJ2-loaded nanoparticle by intramyocardial injection (106 cells/per injection) seven days post-MI. Myocardial infarction was confirmed by echocardiography, and histological analyses of infarct morphology, gap junctions, and angiogenesis were obtained. Our results from immunohistochemical analyses demonstrated the presence of angiogenesis identified in the transplanted region and that there was significant expression of connexin-43 gap junctions, showing a more effective electrical and mechanical integration of the host myocardium. This study suggests that the application of nanoparticle technology in the prevention and treatment of MI is an emerging field and can be a strategy for cardiac repair.

Peroxisome proliferator-activated receptor-gamma (PPARγ) and its immunomodulation function: current understanding and future therapeutic implications.

INTRODUCTION: Pain is a multidimensional experience involving the biological, psychological, and social dimensions of each individual. Particularly, the biological aspects of pain conditions are a response of the neuroimmunology system and the control of painful conditions is a worldwide challenge for researchers. Although years of investigation on pain experience and treatment exist, the high prevalence of chronic pain is still a fact. AREAS COVERED: Peroxisome proliferator-activated receptor-gamma (PPARγ) is a ligand-activated transcription factor belonging to the nuclear hormone receptor superfamily. It regulates several metabolic pathways, including lipid biosynthesis and glucose metabolism, when activated. However, PPARγ activation also has a critical immunomodulatory and neuroprotective effect. EXPERT OPINION: This review summarizes the evidence of synthetic or natural PPARγ ligands such as 15d-PGJ2, epoxyeicosatrienoic acids, thiazolidinediones, and specialized pro-resolving mediators, representing an interesting therapeutic tool for pain control.

Soluble epoxide hydrolase inhibition avoid formalin-induced inflammatory hyperalgesia in the temporomandibular joint.

Epoxyeicosatrienoic acids (EETs) are endogenous molecules that exerts effective antinociceptive and resolutive actions. However, because of their rapid metabolism by the soluble epoxide hydrolase (sEH), EETs are unable to remain bioavailable. Therefore, the aim of this study was to investigate whether local sEH inhibition could prevent inflammatory hyperalgesia in the temporomandibular joint (TMJ) of rats. For that, rats were pre-treated with an intra-TMJ injection of TPPU, followed by the noxious stimulus (1.5% of formalin intra-articular) to evaluate nociceptive behavior. Histological analysis was conducted to explore the inflammatory exudate and mast cell degranulation. Periarticular tissue over the TMJ was used to measure inflammatory lipids and cytokines/chemokine by Enzyme-Linked Immunosorbent Assay (ELISA). We demonstrated that peripheral pretreatment with TPPU prevents formalin-induced inflammatory hyperalgesia in the TMJ, and this effect is strictly local. Moreover, TPPU mitigates the leukocyte exudate in the TMJ, as well as inflammatory lipids mediators. Mast cell number and degranulation were abrogated by TPPU, and the inflammatory cytokine levels were decreased by TPPU. On the other hand, TPPU up-regulated the release of interleukin 10 (IL-10), an anti-inflammatory cytokine. We provide evidence that locally sEH by intra-TMJ injection of TPPU produces an antinociceptive and anti-inflammatory effect on rats' TMJ.

Histological and mast cells evaluation after application of botulinum toxin type a in masseter muscles of rats.

Background: Botulinum Toxin Type A (BTX-A) has been largely used to reduce muscle strength of masseter and temporal muscles by producing a temporary weakening of their activity. This study aimed to evaluate the histological changes and the number of mast cells after the injection of BTX-A. Material and Methods: In the masseter muscle of rats in the periods of 1, 7, 15, and 30 days. These muscles were stained with hematoxylin and eosin (H&E) and toluidine blue (TBO). The presence or absence of an inflammatory process and necrosis were analyzed by H&E in all area of the slide at 10X magnification. The number of mast cells was evaluated by counting 10 "hotspots" in the intra-muscular region on TBO-stained slides, 400X magnification. Statistical analysis was performed through two-way analysis of variance and Tukey's test. Results: As a result, the inflammatory process and necrosis were not observed in any periods studied in both groups Regarding mast cells, there was no statistically significant increase in their quantity in the study group when compared to the control group in the evaluation periods of 7 days and 15 days. However, these mast cells increased significantly during the periods of 1 and 30 days. Conclusions: This study showed that even in the absence of an inflammatory process, there was an increase in the number of mast cells in the first 24 hours after the application of BTX-A, with a subsequent balance between the numbers of mast cells at 7 and 15 days, and again an increase after 30 days. Key words:Botulinum toxins type A, mast cells, masseter muscle.

Biosafety devices to control the spread of potentially contaminated dispersion particles. New associated strategies for health environments.

Dental procedures produce a large amount of spatter and aerosols that create concern for the transmission of airborne diseases, such as Covid-19. This study established a methodology with the objective of evaluating new associated strategies to reduce the risk of cross-transmission in a health environment by simulating spread of potentially contaminated dispersion particles (PCDP) in the environment. This crossover study, was conducted in a school clinic environment (4 clinics containing 12 dental chairs each). As a positive control group (without barriers), 12 professionals activated at the same time the turbine of dental drill, for one minute, with a bacterial solution (Lactobacillus casei Shirota, 1.5x108 CFU/mL), which had been added in the cooling reservoir of the dental equipment. In the experimental groups, the professionals made use of; a) an individual biosafety barrier in dentistry (IBBD) which consists of a metal support covered by a disposable PVC film barrier; b) a Mobile Unit of Disinfection by Ultraviolet-C, consisting of 8 UV lamps-C of 95W, of 304µW/cm2 of irradiance each, connected for 15 minutes (UV-C) and; c) the association between the two methods (IBBD + UV-C). In each clinic, 56 Petri dishes containing MRS agar were positioned on the lamps, benches and on the floor. In addition, plates were placed prior to each test (negative control group) and plates were also placed in the corridor that connects the four clinics. In the groups without barrier and IBBD + UV-C the passive air microorganisms in Petri dishes was also evaluated at times of 30, 60, 90 and 120 minutes after the end of the dental's drill activation. The mean (standard deviation) of CFU of L. casei Shirota for the positive control group was 3905 (1521), while in the experimental groups the mean using the IBBD was 940 (466) CFU, establishing a reduction on average, of 75% (p<0.0001). For the UV-C group, the mean was 260 (309) CFU and the association of the use of IBBD + UV-C promoted an overall average count of 152 (257) CFU, establishing a reduction on average of 93% and 96%, respectively (p<0.0001). Considering these results and the study model used, the individual biosafety barrier associated with UV-C technology showed to be efficient strategies to reduce the dispersion of bioaerosols generated in an environment with high rate of PCDP generation and may be an alternative for the improvement of biosafety in different healthy environment.

Photobiomodulation inhibits inflammation in the temporomandibular joint of rats.

Photobiomodulation (PBM) has been applied as a non-invasive technique for treating temporomandibular joint symptoms, especially on painful condition's relief, however the anti-inflammatory mechanism underlying the effect of PBM remains uncertain. This study aims to evaluate the mechanisms of action of PBM (808 nm) in a carrageenan-induced inflammation on temporomandibular joint (TMJ) of rats. In this study male Wistar rats were pre-treated with irradiation of a low-power diode laser for 15 s on TMJ (infra-red 808 nm, 100 mW, 50 J/cm2 and 1.5 J) 15 min prior an injection in the temporomandibular joint of carrageenan (100 µg/TMJ). 1 h after the TMJ treatments, the rats were terminally anesthetized for joint cavity wash and periarticular tissues collect. Samples analysis demonstrated that PBM inhibit leukocytes chemotaxis in the TMJ and significantly reduces amounts of TNF-α, IL-1ß and CINC-1. In addition, Western blotting analysis demonstrated that PBM significantly decreased the protein levels of P2X3 and P2X7 receptors in the periarticular tissues. On the other hand, PBM was able to increase protein level of IL-10 (anti-inflammatory cytokine). In summary, it is possible to suggest that PBM inhibit inflammatory chemotaxis, modulation the balance of the pro- and anti-inflammatory characteristics of inflammatory cells.

Titanium dioxide nanotubes added to glass ionomer cements affect S. mutans viability and mechanisms of virulence.

This in vitro study evaluated the impact of TiO2 nanotubes (n-TiO2) incorporated into glass ionomer cement (GIC) on Streptococcus mutans (S. mutans) characteristics at cellular and molecular levels. n-TiO2, synthesized by the alkaline method (20 nm in size), was added to Ketac Molar EasyMix® at 0%, 3%, 5%, and 7% by weight. S. mutans strains were cultured on GIC disks with addition or not of n-TiO2 for 1, 3, and 7 days and the following parameters were assessed: inhibition halo (mm) (n=3/group); cell viability (live/dead) (n=5/group); cell morphology (SEM) (n=3/group); and gene expression by real-time PCR (vicR, covR, gtfB, gtfC, and gtfD) (n=6/group). The data were analyzed by the Kruskal-Wallis test, repeated-measures ANOVA or two-way ANOVA, and Tukey's and Dunn's post-hoc tests (α=0.05). The agar diffusion test showed a higher antibacterial property for 5% n-TiO2 compared with 3% and 7% (p<0.05) with no effect of time (1, 3, and 7 days). The cell number was significantly affected by all n-TiO2 groups, while viability was mostly affected by 3% and 5% n-TiO2, which also affected cell morphology and organization. Real-time PCR demonstrated that n-TiO2 reduced the expression of covR when compared with GIC with no n-TiO2 (p<0.05), with no effect of time, except for 3% n-TiO2 on vicR expression. Within-group and between-group analyses revealed n-TiO2 did not affect mRNA levels of gtfB, gtfC, and gtfD (p>0.05). Incorporation of n-TiO2 at 3% and 5% potentially affected S. mutans viability and the expression of key genes for bacterial survival and growth, improving the anticariogenic properties of GIC.

Orofacial musculoskeletal pain: An evidence-based bio-psycho-social matrix model.

Pain is a multidimensional experience comprising sensory-discriminative, affective-motivational, and cognitive-evaluative dimensions. Clinical and research findings have demonstrated a complex interplay between social burdens, individual coping strategies, mood states, psychological disorders, sleep disturbances, masticatory muscle tone, and orofacial musculoskeletal pain. Accordingly, current classification systems for orofacial pain require psychosocial assessments to be an integral part of the multidimensional diagnostic process. Here, we review evidence on how psychosocial and biological factors may generate and perpetuate musculoskeletal orofacial pain. Specifically, we discuss studies investigating a putative causal relationship between stress, bruxism, and pain in the masticatory system. We present findings that attribute brain structures various roles in modulating pain perception and pain-related behavior. We also examine studies investigating how the nervous and immune system on cellular and molecular levels may account for orofacial nociceptive signaling. Furthermore, we review evidence pointing towards associations between orofacial musculoskeletal pain and neuroendocrine imbalances, sleep disturbances, and alterations of the circadian timing system. We conclude with several proposals that may help to alleviate orofacial pain in the future.

The role of adenosine A1 receptor in the peripheral tramadol's effect in the temporomandibular joint of rats.

Peripheral tramadol's delivery in the temporomandibular joint (TMJ) leads to significant analgesic outcomes and inflammatory process's resolvent actions. Mechanistically, these properties are apart from the opioid system. Nevertheless, the molecular mechanisms behind these effects are still unclear. Therefore, the present study investigated the hypothesis that adenosine A1 receptors are involved in the tramadol-induced analgesic and anti-inflammatory effects in the TMJ. Animals were pretreated with an intra-TMJ injection of DPCPX (antagonist of A1 receptor) or tramadol and subsequent nociceptive challenge with an intra-TMJ injection of 1.5% formalin. For over 45 min, the nociceptive behavior was quantitated, and by the end of this assessment, the animals were euthanized, and the periarticular tissue was collected. Lastly, an in vitro assay of BMDM (Bone Marrow-Derived Macrophages) was performed to investigate tramadol activity in macrophages. The intra-TMJ injection of tramadol ameliorates formalin-induced hypernociception along with inhibiting leukocyte migration. The tramadol's peripheral anti-inflammatory effect was mediated by the adenosine A1 receptor and was associated with increased protein expression of α2a-adrenoceptor in the periarticular tissues (p < 0.05: ANOVA, Tukey's test). Also, tramadol inhibits formalin-induced leukocyte migration and protein expression of P2X7 receptors in the periarticular tissue (p < 0.05); however, DPCPX did not alter this effect (p > 0.05). Moreover, DPCPX significantly reduced the protein expression of the M2 macrophage marker, MRC1. In BMDM, tramadol significantly reduces inflammatory cytokines release, and DPCPX abrogated this effect (p < 0.05). We identify tramadol's peripheral effect is mediated by adenosine A1 receptor, possibly expressed in macrophages in the TMJ tissue. We also determined an important discovery related to the activation of A1R/α2a receptors in the tramadol action.

Fast and accurate protocol for histology and immunohistochemistry reactions in temporomandibular joint of rats.

OBJECTIVE: Propose a standard, fast and accurate protocol for the processing of the temporomandibular joint (TMJ) of adults' rats for histology and immunohistochemistry reactions. DESIGN: Wistar male rats were perfused with paraformaldehyde (4 %). The heads were fixed in formaldehyde 10 % solution for 48 h. After that, the heads were sectioned in a sagittal plane and fixed for plus 48 h. Decalcification was performed using 20 % formic acid for 96 h and delimitation of TMJ area was done. Detailed methodology to a standard extraction and processing of TMJ to histological sections is described. Different buffers, equipment, temperature and time were tested to optimize immunostaining. Morphological preservation and antigenicity were evaluated by hematoxylin and eosin staining and immunohistochemistry reaction. RESULTS: The current findings demonstrated that TMJ fixed in 10 % formaldehyde and decalcified in 20 % formic acid optimized decalcification processing time with preservation of cell morphology. Antigen retrieval with citrate buffer in pressure cooker (2 min at 100 °C and 5 min at room temperature) demonstrated the best protocol to preservation of the structures of TMJ. CONCLUSIONS: This work demonstrates in detail a methodology of a fast and accurate TMJ processing for histology and immunohistochemistry reactions that guarantee tissue integrity and quality of staining.

A novel dental biosafety device to control the spread of potentially contaminated dispersion particles from dental ultrasonic tips.

Strategies to return to dental practice in pandemic times is a new challenge due to the generation and spread of potentially contaminated dispersion particles (PCDP) that may contain the SARS-CoV-2, the etiological factor of the COVID-19 disease. Due to the significant dispersion of PCDP in the dental environment, the use of equipment such as ultrasonic tips have been inadvisable during the pandemic. Several clinical procedures, however, benefit from the use of such equipment. Thus, using a microbial dispersion model of PCDP, the aim of this study was to compare the dispersion caused by the dental drill (DD) an ultrasonic tip (UT) alone and the UT coupled with a Spray control (SC) device. The DD, UT (with or without the SC) were activated for one minute having had the water from the reservoir replaced with a suspension of Lactobacillus casei Shirota (1.5 x 108 CFU/mL). Petri dishes containing MRS agar were positioned at 50cm, 100cm and 150cm from the headrest of the dental chair at different angles (0 degree and 90 degrees). At 50 cm, the mean CFU (standard deviation) of L. casei Shirota was 13554.60 (4071.03) for the DD, 286.67 (73.99) for the US (97.89% reduction), and 4.5 (0.58) CFU for the UT-SC (p < 0.0001), establishing a further 98.43% reduction between UT and UT with SC. The UT with SC model proved effective in reducing dispersion from the UT, endorsing its use as an additional strategy to reduce PCDP in the dental environment in times of pandemic.

Occlusion Heightened by Metal Crown Cementation is Aggressive for Periodontal Tissues.

PURPOSE: To investigate the effect of experimental traumatic occlusion (ETO) induced by metal crowns on alveolar bone loss. MATERIALS AND METHODS: Metal crowns were custom-made for the lower first molars with occlusal discrepancy of 0.4 and 0.7 mm from the maximum intercuspation. Thirty-six animals were randomly divided into three groups (n = 12 animals per group): 0.4-mm hyperocclusion group, 0.7-mm hyperocclusion group and the sham group (no metal crown). Twenty-eight days after crown cementation, the animals were euthanized and gingival tissue was collected to assess cytokine levels of IL-17, IL-6, and TNF-α using enzyme-linked immunosorbent assay (ELISA). Mandibles were stained with 1% methylene blue and alveolar bone levels were quantified. Western blotting was used to quantify the expression of receptor activator of nuclear factor κ B (RANK), and its ligand (RANKL), secreted osteoclastogenic factor of activated T cells (SOFAT) and TNF-α-converting enzyme (TACE). Also, mandibles were histologically processed and stained with hematoxylin and eosin, from which the presence of osteoclast-like cells, multinucleated cells containing ≥3 nuclei was counted at 100× magnification. The data were analyzed using one-way ANOVA and Tukey tests. RESULTS: Experimental occlusal trauma for 28 consecutive days significantly increased alveolar bone loss and multinucleated cell counts (p < 0.05). RANK, RANKL, SOFAT, TACE, IL-6, and TNF-α were significantly higher in gingival tissues of ETO groups (p < 0.05). IL-17 titers were unchanged among the groups (p > 0.05). CONCLUSION: Experimental traumatic occlusion activates and sustains bone resorption pathways in the periodontium inducing alveolar bone resorption. As the intensity of occlusal trauma increased, alternative osteoclastic pathways were activated, such as TACE and SOFAT.

Titanium dioxide nanotubes added to glass ionomer cements affect S. mutans viability and mechanisms of virulence

Abstract This in vitro study evaluated the impact of TiO2 nanotubes (n-TiO2) incorporated into glass ionomer cement (GIC) on Streptococcus mutans (S. mutans) characteristics at cellular and molecular levels. n-TiO2, synthesized by the alkaline method (20 nm in size), was added to Ketac Molar EasyMix® at 0%, 3%, 5%, and 7% by weight. S. mutans strains were cultured on GIC disks with addition or not of n-TiO2 for 1, 3, and 7 days and the following parameters were assessed: inhibition halo (mm) (n=3/group); cell viability (live/dead) (n=5/group); cell morphology (SEM) (n=3/group); and gene expression by real-time PCR (vicR, covR, gtfB, gtfC, and gtfD) (n=6/group). The data were analyzed by the Kruskal-Wallis test, repeated-measures ANOVA or two-way ANOVA, and Tukey's and Dunn's post-hoc tests (α=0.05). The agar diffusion test showed a higher antibacterial property for 5% n-TiO2 compared with 3% and 7% (p<0.05) with no effect of time (1, 3, and 7 days). The cell number was significantly affected by all n-TiO2 groups, while viability was mostly affected by 3% and 5% n-TiO2, which also affected cell morphology and organization. Real-time PCR demonstrated that n-TiO2 reduced the expression of covR when compared with GIC with no n-TiO2 (p<0.05), with no effect of time, except for 3% n-TiO2 on vicR expression. Within-group and between-group analyses revealed n-TiO2 did not affect mRNA levels of gtfB, gtfC, and gtfD (p>0.05). Incorporation of n-TiO2 at 3% and 5% potentially affected S. mutans viability and the expression of key genes for bacterial survival and growth, improving the anticariogenic properties of GIC.

Inflammatory cell profile using different autologous fibrin protocols.

Autologous fibrin has been widely used in surgical procedures for both soft and hard tissue repair. There are different protocols and devices to obtain this matrix, with varying centrifugal time, gravity force, speed, angle of the sample tube and spinning radius. The aim of this study was to compare three methods of obtaining autologous fibrin: L-PRF using the Intra-Spin L-PRF centrifuge (Dohan protocol), the advanced PRF (A-PRF) using the Intra-Spin L-PRF centrifuge and autologous leukocyte fibrin (ALF), using the Kasvi centrifuge. Venous blood was collected from 7 healthy volunteers, which were submitted to the 3 different methods of centrifugation. The membranes were tissue-processed and evaluated by immunohistochemistry for CD3, CD20, CD68 and CD138. For CD68+, a lower number of cells was immunolabelled in the L-PRF group when compared to the other groups (A-PRF and ALF). For CD3+, a lower number of immunolabellated cells was observed in the ALF group when compared to the remaining groups (p < 0.05). In the A-PRF group, the CD20+ cell count was lower than in the remaining groups. No difference was observed in CD138+ cell counts between the groups. The 3 protocols tested are suitable for obtaining autologous fibrin membranes.