An in vitro assessment of teething gels' effects on human gingival mesenchymal stem cells.

BACKGROUND: The aim of this study is to examine the cytotoxic effects of dental gels with different contents, which are frequently used during teething, on gingival mesenchymal stem cells (G-MSCs). METHOD: The teething gels used in this study were Dentinox, Gengigel, Osanite, and Jack and Jill. The human gingival mesenchimal stem cells (hG-MSCs) were incubated with these teething gel solutions (0.1%, 50% and 80% concentrations). Reproductive behavior of G-MSCs was monitored in real time for 72 h using the xCELLigence real-time cell analyzer (RTCA) system. Two-way repeated Anova test and post hoc Bonferroni test were used to evaluate the effect of concentration and dental gel on 0-hour and 72-hour viability. Significance was evaluated at p < 0.05 level. RESULTS: Teething gels prepared at 50% concentration are added to the G-MSC culture, the "cell index" value of G-MSCs to which Dentinox brand gel is added is significantly lower than all other groups (p = 0.05). There is a statistically significant difference between the concentrations in terms of cell index values at the 72nd hour compared to the 0th hour (p = 0.001). CONCLUSIONS: The local anesthetic dental gels used in children have a more negative effect on cell viability as concentration increases.

Cytotoxic effect of dental luting cement on human gingival mesenchymal stem cell and evaluation of cytokines and growth factor release - An in vitro study.

AIM: In routine dental care, various dental luting cements are utilized to cement the dental prosthesis. Thus, the aim of the current study was to assess the Cytotoxic effect of three different dental luting cements on human gingival mesenchymal stem cell and evaluation of cytokines and growth factors release. SETTINGS AND DESIGN: Cytotoxicity of glass ionomer cement (GIC), resin modified glass ionomer cement (RMGIC) and resin cement (RC) on the human gingival mesenchymal stem cells (HGMSCs) was evaluated. Amongst the cements tested, least cytotoxic cement was further tested for the release of cytokines and growth factors. MATERIALS AND METHODS: MTT test was used to evaluate the cytotoxicity of the dental luting cements at 1 h, 24 h, and 48 h on HGMSCs. Cytokines such as interleukin (IL) 1α & IL 8 and growth factors such as platelet derived growth factor & transforming growth factor beta release from the least cytotoxic RC was evaluated using flow cytometry analysis. STATISTICAL ANALYSIS USED: The mean absorbance values by MTT assay and cell viability at various time intervals between four groups were compared using a one way analysis of variance test and Tukey's post hoc test. The least cytotoxic RC group and the control group's mean levels of cytokines and growth factors were compared using the Mann-Whitney test. RESULT: As exposure time increased, the dental luting cement examined in this study were cytotoxic. RC was the least cytotoxic, RMGIC was moderate and glass ionomer cement showed the highest cytotoxic effect. Concomitantly, a significant positive biological response of gingival mesenchymal stem cells with the release of ILs when exposed to the RC was observed. CONCLUSION: For a fixed dental prosthesis to be clinically successful over the long term, it is imperative that the biocompatibility of the luting cement be taken into account in order to maintain a healthy periodontium surrounding the restoration.

Effect of nano zinc oxide on proliferation and toxicity of human gingival cells.

BACKGROUND: Periodontal dressing is used to cover the gum surface and protect the wound after periodontal surgery. Nanomaterials have been widely applied in dentistry in recent years. Zinc oxide (ZnO) is one of the main components of periodontal dressing. AIM: This study aims to explore the toxicity ZnO nanoparticles (ZnO NPs) causes to human gingival fibroblast cells (HGF-1) and its effect on cell proliferation. METHODS: First, we identified and analyzed HGF-1, including cell morphology, growth curve, and immunohistochemistry staining. Then, we treated HGF-1 with ZnO NP. Cell viability, the integrity of the cell membrane, oxidative damage, and apoptosis were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) release assay, fluorescent probe, and flow cytometry. Furthermore, the expression of murine double minute 2 (MDM2) and p53 was determined by quantitative real-time polymerase chain reaction (qPCR) and Western blotting. We finally overexpressed MDM2 in HGF-1 to verify the relationship between MDM2 and cell proliferation. RESULTS: Our research indicated ZnO NPs did not affect cell proliferation at low concentrations. However, high-concentration ZnO NP inhibited cell proliferation, destroyed the integrity of cell membranes, and induced oxidative stress and apoptosis. In addition, high concentration of ZnO NPs inhibited the proliferation of HGF-1 by regulating the expression of MDM2 and p53. CONCLUSION: High concentration of ZnO NP caused toxicity to HGF-1 cells and inhibited cell proliferation by regulating MDM2 and p53 expression.

Reduction of oxidative stress blunts the NLRP3 inflammatory cascade in LPS stimulated human gingival fibroblasts and oral mucosal epithelial cells.

The therapeutic armamentarium for the treatment of oral mucositis is very poor. Catechin and baicalin are two natural flavonoids that have been individually reported to have a curative potential. Flavocoxid is a mixed extract containing baicalin and catechin showing antioxidant effects and anti-inflammatory activity mainly due to a dual inhibition of inducible cyclooxygenase (COX-2), 5-lipoxygenase (5-LOX) and NLRP3 pathway. The aim of this study was to evaluate the anti-inflammatory and anti-oxidant effects of flavocoxid in an "in vitro" model of oral mucositis induced by triggering an inflammatory phenotype in human gingival fibroblasts (GF) and human oral mucosal epithelial cells (EC). GF and EC were challenged with lipopolysaccharide (LPS 2 µg/ml) alone or in combination with flavocoxid (32 µg/ml). Flavocoxid increased Nrf2, prompted a marked reduction in malondialdehyde levels and reduced the expression of COX-2 and 5-LOX together with PGE2, and LTB4 levels. Flavocoxid caused also a great decrease in the expression of NF-κB and turned off NLRP3 inflammasome and its downstream effectors signal, as caspase-1, IL-1ß and IL-18 in both GF and EC cells stimulated with LPS. These results suggest a correlation between oxidative stress and NLRP3 activation and indicate that flavocoxid suppresses the inflammatory storm that accompanies oral mucositis. This preclinical evidence deserves to be confirmed in a clinical setting.

Quercetin Preserves Oral Cavity Health by Mitigating Inflammation and Microbial Dysbiosis.

Failure to attenuate inflammation coupled with consequent microbiota changes drives the development of bone-destructive periodontitis. Quercetin, a plant-derived polyphenolic flavonoid, has been linked with health benefits in both humans and animals. Using a systematic approach, we investigated the effect of orally delivered Quercetin on host inflammatory response, oral microbial composition and periodontal disease phenotype. In vivo, quercetin supplementation diminished gingival cytokine expression, inflammatory cell infiltrate and alveolar bone loss. Microbiome analyses revealed a healthier oral microbial composition in Quercetin-treated versus vehicle-treated group characterized by reduction in the number of pathogenic species including Enterococcus, Neisseria and Pseudomonas and increase in the number of non-pathogenic Streptococcus sp. and bacterial diversity. In vitro, Quercetin diminished inflammatory cytokine production through modulating NF-κB:A20 axis in human macrophages following challenge with oral bacteria and TLR agonists. Collectively, our findings reveal that Quercetin supplement instigates a balanced periodontal tissue homeostasis through limiting inflammation and fostering an oral cavity microenvironment conducive of symbiotic microbiota associated with health. This proof of concept study provides key evidence for translational studies to improve overall health.

Effect of nano zinc oxide on proliferation and toxicity of human gingival cells.

BACKGROUND: Periodontal dressing is used to cover the gum surface and protect the wound after periodontal surgery. Nanomaterials have been widely applied in dentistry in recent years. Zinc oxide (ZnO) is one of the main components of periodontal dressing. AIM: This study aims to explore the toxicity ZnO nanoparticles (ZnO NPs) causes to human gingival fibroblast cells (HGF-1) and its effect on cell proliferation. METHODS: First, we identified and analyzed HGF-1, including cell morphology, growth curve, and immunohistochemistry staining. Then, we treated HGF-1 with ZnO NP. Cell viability, the integrity of the cell membrane, oxidative damage, and apoptosis were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) release assay, fluorescent probe, and flow cytometry. Furthermore, the expression of murine double minute 2 (MDM2) and p53 was determined by quantitative real-time polymerase chain reaction (qPCR) and Western blotting. We finally overexpressed MDM2 in HGF-1 to verify the relationship between MDM2 and cell proliferation. RESULTS: Our research indicated ZnO NPs did not affect cell proliferation at low concentrations. However, high-concentration ZnO NP inhibited cell proliferation, destroyed the integrity of cell membranes, and induced oxidative stress and apoptosis. In addition, high concentration of ZnO NPs inhibited the proliferation of HGF-1 by regulating the expression of MDM2 and p53. CONCLUSION: High concentration of ZnO NP caused toxicity to HGF-1 cells and inhibited cell proliferation by regulating MDM2 and p53 expression.

PDRN, a natural bioactive compound, blunts inflammation and positively reprograms healing genes in an "in vitro" model of oral mucositis.

Oral mucositis is a side effect hard to treat following high dose chemotherapy or radiotherapy. Adenosine A2A receptor stimulation blocks NF-κB and boosts the Wnt/ß-catenin signaling, thus blunting inflammation and triggering growth factor codifying genes. Polydeoxyribonucleotide (PDRN) is a registered drug that activates the A2A receptor. Therefore, the aim of this study was to evaluate PDRN effects in an "in vitro" model of oral mucositis induced by prompting an inflammatory phenotype in human gingival fibroblasts (GF) and human oral mucosal epithelial cells (EC). GF and EC were stimulated with LPS (2 µg/ml) alone or in combination with i) PDRN (100 µg/ml); ii) PDRN plus ZM241385 (1 µM) as an A2AR antagonist; iii) CGS21680 (1 µM) as an A2AR agonist. LPS boosted NF-κB, TNF-α and IL-6 expression, decreased IL-10 levels and downregulated both Wnt/ß-catenin, VEGF and EGF expression. PDRN reverted the LPS-induced phenotype as well as CGS21680. Co-incubation with ZM241385 abolished PDRN effects, thus confirming A2A receptor involvement in PDRN mechanism of action. These results suggest that PDRN efficacy may be due to a "dual mode" of action: NF-κB inhibition and Wnt/ß-catenin signaling activation. However, these interesting findings need to be confirmed by animal and clinical studies.

hTERT-immortalized gingival fibroblasts respond to cytokines but fail to mimic primary cell responses to Porphyromonas gingivalis.

In periodontitis, gingival fibroblasts (GFs) interact with and respond to oral pathogens, significantly contributing to perpetuation of chronic inflammation and tissue destruction. The aim of this study was to determine the usefulness of the recently released hTERT-immortalized GF (TIGF) cell line for studies of host-pathogen interactions. We show that TIGFs are unable to upregulate expression and production of interleukin (IL)-6, IL-8 and prostaglandin E2 upon infection with Porphyromonas gingivalis despite being susceptible to adhesion and invasion by this oral pathogen. In contrast, induction of inflammatory mediators in TNFα- or IL-1ß-stimulated TIGFs is comparable to that observed in primary GFs. The inability of TIGFs to respond directly to P. gingivalis is caused by a specific defect in Toll-like receptor-2 (TLR2) expression, which is likely driven by TLR2 promoter hypermethylation. Consistently, TIGFs fail to upregulate inflammatory genes in response to the TLR2 agonists Pam2CSK4 and Pam3CSK4. These results identify important limitations of using TIGFs to study GF interaction with oral pathogens, though these cells may be useful for studies of TLR2-independent processes. Our observations also emphasize the importance of direct comparisons between immortalized and primary cells prior to using cell lines as models in studies of any biological processes.

Expression of osteoclastogenic and anti-osteoclastogenic cytokines differs in mouse gingiva injected with lipopolysaccharide, peptidoglycan, or both.

OBJECTIVE: Bacterial substances in subgingival biofilm evoke alveolar bone resorption. We previously reported that gingival injection of bacterial lipopolysaccharide (LPS) and peptidoglycan (PGN) induced alveolar bone resorption in mice. However, the mechanism by which LPS and PGN induce osteoclast formation has not been investigated. The aim of this study is to clarify the role of osteoclastogenic and anti-osteoclastogenic cytokines in the alveolar bone resorption induced by LPS and PGN. MATERIALS: LPS from Escherichia coli, PGN from Staphylococcus aureus, or both were injected into the gingiva of mice every 48 h for a total of 13 times. Alveolar bone resorption was assessed histochemically by tartrate-resistant acid phosphatase staining. Expression of the receptor activator of nuclear factor-κB ligand (RANKL), tumor necrosis factor (TNF)-α, interleukin (IL)-17, and IL-10 were analyzed by immunostaining. To analyze the role of these cytokines, RANKL-pretreated mouse bone marrow macrophages were stimulated with LPS, PGN, or LPS + PGN with or without anti-TNF-α antibody, IL-17, or IL-10. RESULTS: Alveolar bone resorption was induced by both LPS and PGN and exacerbated by LPS + PGN. LPS induced higher RANKL expression than PGN. Expression of TNF-α and IL-10 was correlated with bone resorption. PGN injections induced the strongest expression of IL-17, followed by LPS + PGN and LPS. In an in vitro osteoclastogenesis assay, anti-TNF-α antibody and IL-10 inhibited osteoclast formation, but IL-17 promoted it. CONCLUSION: LPS, PGN, or LPS + PGN injections induce distinctive expression of TNF-α, IL-10, and IL-17, suggesting that the composition of these bacterial ligands in dental plaque is critical for alveolar bone resorption.

Halofuginone functions as a therapeutic drug for chronic periodontitis in a mouse model.

Periodontitis is an inflammatory disease caused by host immune response, resulting in a loss of periodontium and alveolar bone. Immune cells, such as T cells and macrophages, play a critical role in the periodontitis onset. Halofuginone, a natural quinazolinone alkaloid, has been shown to possess anti-fibrosis, anti-cancer, and immunomodulatory properties. However, the effect of halofuginone on periodontitis has never been reported. In this study, a ligature-induced mice model of periodontitis was applied to investigate the potential beneficial effect of halofuginone on periodontitis. We demonstrated that the administration of halofuginone significantly reduced the expression levels of pro-inflammatory cytokines (IL-1ß, IL-6, and TNF-α) in vivo, and markedly suppressed immune cell infiltration into the infected sites. Furthermore, we also observed that halofuginone treatment blocked the T-helper 17 (Th17) cell differentiation in vivo and in vitro. We demonstrated for the first time that halofuginone alleviated the onset of periodontitis through reducing immune responses.

Glucagon-Like Peptide-1 Receptor Agonist Liraglutide Ameliorates the Development of Periodontitis.

Periodontitis is one of the diabetic complications due to its high morbidity and severity in patients with diabetes. The prevention of periodontitis is especially important in diabetic patients because the relationship between diabetes and periodontitis is bidirectional. Here, we evaluated the impacts of glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide on the amelioration of periodontitis. Five-wk-old Male Sprague-Dawley (SD) rats (n = 30) were divided into 3 groups: normal, periodontitis, and periodontitis with liraglutide treatment groups. Periodontitis was induced by ligature around the maxillary second molar in SD rats. Half of the rats were administered liraglutide for 2 weeks. Periodontitis was evaluated by histological staining, gene expressions of inflammatory cytokines in gingiva, and microcomputed tomography. Periodontitis increased inflammatory cell infiltration, macrophage accumulation, and gene expressions of tumor necrosis factor-α and inducible nitric oxide synthase in the gingiva, all of which were ameliorated by liraglutide. Liraglutide decreased M1 macrophages but did not affect M2 macrophages in periodontitis. Moreover, ligature-induced alveolar bone resorption was ameliorated by liraglutide. Liraglutide treatment also reduced osteoclasts on the alveolar bone surface. These results highlight the beyond glucose-lowering effects of liraglutide on the treatment of periodontitis.

Gingival epithelium attachment to well- or partially cured resin composites.

Ideal restoration material for caries would allow attachment of gingival epithelia. The attachment of epithelial cells to specimens of the 4 most commercially used well- or partially-cured resin composites, with and without TEGDMA, was assessed. Effects of resin composite on the Ca9-22 gingival epithelial cell-line were assessed by measuring the cytotoxicity, viability and gene expression for attachment, apoptosis, ROS-production, pro-inflammatory cytokines, and matrix metalloproteinases. As controls, cells on tissue culture plastic or bovine tooth enamel specimens were used. Significantly less cell attachment was measured on freshly made resin-composite specimens. Concomitantly, significantly higher cytotoxicity was measured in the presence of freshly made resin-composite specimens. However, after 8 d of leakage, the cell attachment to and cytotoxicity of the resin composite was comparable to bovine tooth enamel. Significantly higher expressions of IL6, MMP2, BCL6 and ITGA4 were measured in cells attached to resin-composite surfaces than controls. There were no significant differences between the results using different conditions of resin composite, with or without TEGDMA and well or partially cured. Less cell attachment and presence of more inflammatory markers were observed on all freshly-made resin-composite surfaces. However, after a leakage period attachment of cells to the resin composite improved to the level of natural tooth materials such as enamel. This indicated that the negative effects of resin composites on epithelial cells might be transient.

Consecutive intra-gingival injections of lipopolysaccharide and butyric acid to mice induce abnormal behavior and changes in cytokine concentrations.

BACKGROUND: Periodontopathic bacteria such as Porphyromonas gingivalis produce several metabolites, including lipopolysaccharide (LPS) and n-butyric acid (BA). Past work suggested that periodontal infection may cause cognitive impairment in mice. AIMS: To elucidate the mechanisms by which metabolites such as LPS and BA, resulting from Porphyromonas gingivalis activity, induce immunological and physiological abnormalities in mice. METHODS: In the present work, 28 male ICR mice were placed in an open-field arena and the total distance (cm/600 s) they covered was recorded. Based on their moving distances, mice were divided into 4 groups (n = 7) and injected the following substances into their gingival tissues for 32 consecutive days: saline (C), 5 mmol/L of BA (B), 1 µg/mouse of LPS (L), and BA-LPS (BL) solutions. Distances covered by mice were also measured on days 14 and 21, with their habituation scores considered as "(moving distance on day 14 or 21)/(moving distance on day 0)". Afterwards, mice were dissected, and hippocampal gene expression and the concentrations of short-chain fatty acids, neurotransmitters and cytokines in their blood plasma and brains were analyzed. In addition, mouse brain and liver tissues were fixed and visually assessed for histopathological abnormalities. RESULTS: Group BL had significantly higher habituation scores than C and B on day 14. LPS induced higher habituation scores on day 21. LPS induced significant decreases in the mRNA levels of interleukin (IL)-6 and brain-derived neurotrophic factors, and an increase in neurotrophic tyrosine kinase receptor type 2. In both plasma and brain, LPS induced a significant acetate increase. Moreover, LPS significantly increased acetylcholine in brain. In plasma alone, LPS and BA significantly decreased monocyte chemoattractant protein 1 (MCP-1). However, while LPS significantly decreased tyrosine, BA significantly increased it. Lastly, LPS significantly decreased IL-6 and tumor necrosis factor in plasma. No histopathological abnormalities were detected in liver or brain tissues of mice. CONCLUSION: We showed that injections of LPS and/or BA induced mice to move seemingly tireless and that both LPS and BA injections strongly induced a reduction of MCP-1 in blood plasma. We concluded that LPS and BA may have been crucial to induce and/or aggravate abnormal behavior in mice.

Analysis of cell-biomaterial interaction through cellular bridge formation in the interface between hGMSCs and CaP bioceramics.

The combination of biomaterials and stem cells for clinical applications constitute a great challenge in bone tissue engineering. Hence, cellular networks derived from cells-biomaterials crosstalk have a profound influence on cell behaviour and communication, preceding proliferation and differentiation. The purpose of this study was to investigate in vitro cellular networks derived from human gingival mesenchymal stem cells (hGMSCs) and calcium phosphate (CaP) bioceramic interaction. Biological performance of CaP bioceramic and hGMSCs interaction was evaluated through cell adhesion and distribution, cellular proliferation, and potential osteogenic differentiation, at three different times: 5 h, 1 week and 4 weeks. Results confirmed that hGMSCs met the required MSCs criteria while displaying osteogenic differentiaton capacities. We found a significant increase of cellular numbers and proliferation levels. Also, protein and mRNA OPN expression were upregulated in cells cultured with CaP bioceramic by day 21, suggesting an osteoinductible effect of the CaP bioceramic on hGMSCs. Remarkably, CaP bioceramic aggregations were obtained through hGMSCs bridges, suggesting the in vitro potential of macrostructures formation. We conclude that hGMSCs and CaP bioceramics with micro and macropores support hGMSC adhesion, proliferation and osteogenic differentiation. Our results suggest that investigations focused on the interface cells-biomaterials are essential for bone tissue regenerative therapies.

Cytotoxicity of dental disclosing solution on gingival epithelial cells in vitro.

OBJECTIVE: Coloring dental biofilm and plaque with a dental disclosing solution is visually effective in dental treatment and oral hygiene education. Despite continuous reports of the risk of the product ingredients, dental disclosing solution are widely used in dentistry. However, the cytotoxic mechanism of dental disclosing solution is not known. Here we elucidated the tissue dyeing range and investigated the cytotoxic mechanism of dental disclosing solution. MATERIALS AND METHODS: Gingival epithelial cells and mouse head and neck tissue were stained with dental disclosing solution. Changes in the cell cycle distribution by the dental disclosing solution treatment were analyzed. A deoxynucleotidyl transferase dUTP nick and labeling (TUNEL) assay was performed to examine the apoptotic features of the gingival epithelial cells. RESULTS: Dental disclosing solution stained the chromosome strongly, as well as both the hard and soft tissue of the mouse head and neck. The results of flow cytometric analysis and TUNEL analyses revealed that the cytotoxicity associated with dental disclosing solution was related to the induction of apoptosis. However, the staining of porcine skin by dental disclosing solution was not easily removed, even with a wide range of pH solutions. CONCLUSIONS: These results suggest that dental disclosing solution had strong cytotoxicity and safer alternatives are needed.

Curcumin-Loaded Bacterial Cellulose/Alginate/Gelatin as A Multifunctional Biopolymer Composite Film.

Multifunctional biopolymer composites comprising mechanically-disintegrated bacterial cellulose, alginate, gelatin and curcumin plasticized with glycerol were successfully fabricated through a simple, facile, cost-effective mechanical blending and casting method. SEM images indicate a well-distributed structure of the composites. The water contact angles existed in the range of 50-70°. Measured water vapor permeability values were 300-800 g/m2/24 h, which were comparable with those of commercial dressing products. No release of curcumin from the films was observed during the immersion in PBS and artificial saliva, and the fluid uptakes were in the range of 100-700%. Films were stretchable and provided appropriate stiffness and enduring deformation. Hydrated films adhered firmly onto the skin. In vitro mucoadhesion time was found in the range of 0.5-6 h with porcine mucosa as model membrane under artificial saliva medium. The curcumin-loaded films had substantial antibacterial activity against E. coli and S. aureus. The films showed non-cytotoxicity to human keratinocytes and human gingival fibroblasts but exhibited potent anticancer activity in oral cancer cells. Therefore, these curcumin-loaded films showed their potential for use as leave-on skin applications. These versatile films can be further developed to achieve desirable characteristics for local topical patches for wound care, periodontitis and oral cancer treatment.

Effect of thymoquinone on Fusobacterium nucleatum­associated biofilm and inflammation.

Periodontitis affects oral tissues and induces systemic inflammation, which increases the risk of cardiovascular disease and metabolic syndrome. Subgingival plaque accumulation is a trigger of periodontitis. Fusobacterium nucleatum (FN) contributes to subgingival biofilm complexity by intercalating with early and late bacterial colonizers on tooth surfaces. In addition, inflammatory responses to FN are associated with the progression of periodontitis. Nigella sativa Lin. seed, which is known as black cumin (BC), has been used as a herbal medicine to treat ailments such as asthma and infectious diseases. The current study examined the inhibitory effect of BC oil and its active constituents, thymol (TM) and thymoquinone (TQ), on FN­associated biofilm and inflammation. FN­containing biofilms were prepared by co­cultivation with an early dental colonizer, Actinomyces naeslundii (AN). The stability and biomass of FN/AN dual species biofilms were significantly higher compared with FN alone. This effect was retained even with prefixed cells, indicating that FN/AN co­aggregation is mediated by physicochemical interactions with cell surface molecules. FN/AN biofilm formation was significantly inhibited by 0.1% TM or TQ. Confocal laser scanning microscopy indicated that treatment of preformed FN/AN biofilm with 0.01% of BC, TM or TQ significantly reduced biofilm thickness, and TQ demonstrated a cleansing effect equivalent to that of isopropyl methylphenol. TQ dose­dependently suppressed TNF­α production from a human monocytic cell line, THP­1 exposed to FN, yet showed no toxicity to THP­1 cells. These results indicated that oral hygiene care using TQ could reduce FN­associated biofilm and inflammation in gingival tissue.

Effect of Hyaluronic Acid Filler Injection on the Interdental Papilla in a Mouse Model of Open Gingival Embrasure.

The black triangle resulting from interdental papilla (IDP) loss is associated with poor aesthetics and difficulty in pronunciation and food impaction. There is limited knowledge of gingival tissue inflammatory response to hyaluronic acid (HA) filler injection, a minimally invasive IDP reconstruction method. This study aimed to examine the morphological and histological changes in IDP and the inflammatory cytokine localization to the IDP post-HA filler injection using an open gingival embrasure (OGE) mouse model. Mice from the control, sham, and OGE groups were attached with reference, inactive, and activated wires for 5 days, respectively. The degree of IDP loss was determined based on the spring-papilla distance (SPD). Morphological and histological changes in the OGE group injected with phosphate-buffered saline (PBS) or HA fillers were examined on days 2 and 7 post-injection. Immunohistochemical analysis was performed to determine the localization patterns of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, myeloperoxidase (MPO), and Ki67. Five days post-wire attachment, the control and OGE groups exhibited a significantly higher SPD than the sham group (p < 0.0167). The SPD of the HA filler injection group was significantly lower than that of the PBS injection group on days 2, 4, and 7 post-injection (p < 0.05). The IDP of the OGE group was wide and flat. HA filler was stable in the connective tissue underlying the epithelial tissue even on day 7 post-injection. TNF-α, IL-1ß, IL-6, MPO, and Ki67 were highly localized to the connective tissue surrounding the filler on day 2, which decreased on day 7 post-injection. Thus, HA filler can safely and successfully reconstruct the IDP in cases of OGE.

Development of a thermosensitive statin loaded chitosan-based hydrogel promoting bone healing.

Statins have been proposed as potential adjuvant to periodontal treatment due to their pleiotropic properties. A new thermosensitive chitosan hydrogel loaded with statins (atorvastatin and lovastatin) nanoemulsions was synthesized to allow a spatially controlled local administration of active compounds at lesion site. Spontaneous nano-emulsification method was used to synthesize statins loaded nanoemulsions. In vitro, atorvastatin and lovastatin loaded nanoemulsions were cytocompatible and were able to be uptake by oral epithelial cells. Treatment of Porphyromonas gingivalis infected oral epithelial cells and gingival fibroblasts with atorvastatin and lovastatin loaded nanoemulsions decreased significantly pro-inflammatory markers expression (TNF-α and IL-1ß) and pro-osteoclastic RANKL. Nevertheless, such treatment induced the expression of Bone sialoprotein 2 (BSP2) in osteoblast emphasizing the pro-healing properties of atorvastatin and lovastatin nanoemulsions. In vivo, in a calvarial bone defect model (2 mm), treatment with the hydrogel loaded with atorvastatin and lovastatin nanoemulsions induced a significant increase of the neobone formation in comparison with systemic administration of statins. This study demonstrates the potential of this statins loaded hydrogel to improve bone regeneration and to decrease soft tissue inflammation. Its use in the specific context of periodontitis management could be considered in the future with a reduced risk of side effects.