Associated factors of periodontitis and predicted study among young man in China: a population-based cross-sectional study.

BACKGROUND: Periodontitis represents the foremost oral condition in young men, strongly correlated with socioeconomic elements and oral health behaviors. This research aimed to assess the prevalence of periodontitis and associated associations with socio-demographics and oral health practices for subsequent Hazard Ratio (HR) estimation. METHODS: A total of 46,476 young men were recruited to the study between August 2022 and October 2023. A questionnaire on socio-demographic factors and oral health-related behaviors related to periodontitis was completed. The standard procedure was used for oral examination. Logistic regression and hazard ratios were used to estimate the influencing factors, whereas the nomogram was used to predict the risk of periodontitis in young men. RESULTS: A total of 46,476 young men were surveyed and completed the questionnaire. The overall prevalence of periodontitis among young men was 1.74%. Out of these, 1.7% had mild periodontitis and 0.6% had moderate periodontitis. Age and dental calculus were important factors in the periodontal health of young men. This nomogram, which includes 7 easily obtainable clinical characteristics routinely collected during periodontitis risk assessment, provides clinicians with a user-friendly tool to assess the risk of periodontal disease in young men. CONCLUSIONS: Regular dental prophylaxis is crucial for young men to maintain their gingival health and prevent the onset of periodontitis. Dental calculus plays a prominent role in this matter, as it serves as a significant contributing factor.

Effect of Polymer and Crosslinker Concentration on Static and Dynamic Gelation Behavior of Phenolic Resin Hydrogel.

The application results of profile control and water plugging technology are highly related to the gelation time and strength of phenolic resin hydrogel. In this work, a hydrogel solution was prepared by fully mixing the prepared polymer solution with a crosslinker. The static gelation process of PFR hydrogel in ampoule bottles and porous media was analyzed by changes in the viscosity and residual resistance coefficient. Then, the dynamic gelation of the PFR hydrogel in porous media was tested using a circulating flow device, and the changes in viscosity and injection pressure were analyzed during the dynamic gelation process. Finally, the effects of the polymer concentration and crosslinker concentration on dynamic gelation were analyzed. The initial gelation time and final gelation time in porous media were 1-1.5 times and 1.5-2 times those in ampoule bottles under static conditions, respectively. The initial dynamic gelation time in porous media was 2-2.5 times and 1.5-2 times the initial static gelation times in ampoule bottles and porous media, respectively. The final dynamic gelation time was four times and two times the initial static gelation times in ampoule bottles and porous media, respectively. The production after dynamic gelation in porous media comprised hydrogel aggregates and water fluid, leading to a high injection pressure and low viscosity of the produced liquid. As the concentration of polymer and crosslinker increased, the dynamic gelation time was shortened and the gel strength was increased. In the dynamic gelation process in porous media, the phenol resin hydrogel could migrate deeply, but it was limited by the concentrations of the polymer and crosslinker. The results of subsequent water flooding showed that the polymer hydrogel had a good plugging ability after dynamic gelation. The deep reservoir could only be blocked off in the subsequent water flooding process when the migration of hydrogel happened in the dynamic gelation process.

Nano implant surface triggers autophagy through membrane curvature distortion to regulate the osteogenic differentiation.

Anodized titania nanotubes have been considered as an effective coating for bone implants due to their ability to induce osteogenesis, whereas the osteogenic mechanism is not fully understood. Our previous study has revealed the potential role of autophagy in osteogenic regulation of nanotubular surface, whereas how the autophagy is activated remains unknown. In this study, we focused on the cell membrane curvature-sensing protein Bif-1 and its effect on the regulation of autophagy. Both autophagosomes formation and autophagic flux were enhanced on the nanotubular surface, as indicated by LC3-II accumulation and p62 degradation. In the meanwhile, the Bif-1 was significantly upregulated, which contributed to autophagy activation and osteogenic differentiation through Beclin-1/PIK3C3 signaling pathway. In conclusion, these findings have bridged the gap between extracellular physical nanotopography and intracellular autophagy activation, which may provide a deeper insight into the signaling transition from mechanical to biological across the cell membrane.

Periodontal disease and risk of Alzheimer's disease: A two-sample Mendelian randomization.

BACKGROUND: Evidence from observational studies and clinical trials suggests an association between periodontal disease and Alzheimer's disease (AD). However, the causal relationship between periodontal disease and AD remains to be determined. METHODS: We obtained periodontal disease data from the FinnGen database and two sets of AD data from the IEU consortium and PGC databases. Subsequently, we conducted a two-sample Mendelian randomization (MR) analysis to investigate the causal relationship between periodontal disease and AD. RESULTS: The results of the random-effects IVW analysis revealed no evidence of a genetic causal relationship between periodontal disease and AD, regardless of whether the AD data from the IEU consortium or the AD data from the PGC database were utilized. No heterogeneity, multiple effects of levels, or outliers were observed in this study. CONCLUSIONS: Our findings indicate that there is no causal relationship between periodontal disease and AD at the genetic level.

Association between obesity and fracture risk in Chinese women above 50 years of age: a prospective cohort study.

BACKGROUND: Fractures present serious health challenges for older adults, including premature mortality and reduced quality of life. Obesity has become significantly prevalent in China. However, the association between obesity and fractures remains unclear. This study aimed to assess the association between obesity and fractures among Chinese women above 50 years of age. METHODS: A prospective cohort study was designed based on the China Health and Nutrition Survey, using data from 1997 to 2015. The average follow-up duration was seven years. Trained investigators measured body mass index (BMI) and waist circumference (WC) at baseline. Obesity was defined according to World Health Organization recommendations. Waist-to-height ratio (W-HtR) was calculated, with 0.5 as the cutoff value. Onset of fractures, self-reported by the participants during the follow-up period, was the primary outcome. Cox hazard regression models were used to assess the association between BMI, WC, W-HtR and subsequent risk of fracture. A sensitivity analysis was conducted by multiple imputation of missing data on the variables at baseline. RESULTS: A total of 2,641 women aged ≥ 50 years were involved in the study. In all the models, no significant association existed between BMI and fracture risk. However, women with WC ≥ 88 cm had significantly higher risk of fracture than those with WC < 80 cm according to both the unadjusted (HR = 1.744, 95% CI: 1.173-2.591) and adjusted models (HR = 1.796, 95% CI: 1.196-2.695). In addition, W-HtR and fracture risk were positively associated according to both the unadjusted (HR = 1.798, 95% CI: 1.230-2.627) and adjusted models (HR = 1.772, 95% CI: 1.209-2.599). Results of the sensitivity analysis were consistent with those of the above analyses. CONCLUSIONS: Abdominal obesity increased the risk of all-cause fractures in Chinese women ≥ 50 years old. Intervention strategies and measures to prevent or address abdominal obesity would be helpful to decrease the fracture incidence.

Research Models in Dentine Development and Regeneration.

Dentine is a major component of teeth and is responsible for many of their functions, such as mastication and neural sensation/transduction. Over the past decades, numerous studies have focused on dentine development and regeneration using a variety of research models, including in vivo, ex vivo and in vitro models. In vivo animal models play a crucial role in the exploration of biochemical factors that are involved in dentine development, whereas ex vivo and in vitro models contribute mainly to the identification of biophysical factors in dentine regeneration, of which mechanical force is most critical. In the present review, research models involved in studies related to dentine development and regeneration were screened from publications released in recent years and summarised comprehensively, particularly in vivo animal models including prokaryotic microinjection, Cre/LoxP, CRISPR/Cas9, ZFN and TALEN, and scaffold-based in vitro and ex vivo models. The latter were further divided by the interactive forces. Summarising these research models will not only benefit the development of future dentine-related studies but also provide hints regarding the evolution of novel dentine regeneration strategies.

Piezo1 mediates the degradation of cartilage extracellular matrix in malocclusion-induced TMJOA.

OBJECTIVES: To evaluate the role of Piezo1 in the malocclusion-induced osteoarthritic cartilage of the temporomandibular joint. METHODS: A temporomandibular joint osteoarthritis model was established using a unilateral anterior crossbite in vivo, and cartilage degeneration and Piezo1 expression were observed by histological and immunohistochemical staining. ATDC5 cells were loaded with 24 dyn/cm2 fluid flow shear stress using the Flexcell device in vitro and expression and function of Piezo1 were evaluated. After identifying the function of Piezo1 in YAP translocation under FFSS conditions, the influence of Piezo1 and YAP on metabolism-related enzymes under FFSS was detected through a real-time polymerase chain reaction analysis and western blotting. A UAC-TMJ injection model was established to observe the therapeutic effect of intra-articular injection of a Piezo1 inhibitor on osteoarthritic cartilage matrix loss. RESULTS: Piezo1 was overexpressed in the osteoarthritic cartilage and cultured chondrocytes under shear stress. Piezo1 Silencing inhibited the nuclear translocation of YAP and subsequently downregulated the expression of MMP13 and ADAMTS5. Intra-articular injection of the Piezo1 inhibitor, GsMTx4, could ameliorate proteoglycan degradation in malocclusion-induced TMJOA and suppressed MMP13 and ADAMTS5 expression. CONCLUSIONS: Our results revealed that the activation of Piezo1 promotes mechanical-induced cartilage degradation through the YAP-MMP13/ADAMTS5 signaling pathway.

Functional microspheres for tissue regeneration.

As a new type of injectable biomaterials, functional microspheres have attracted increasing attention in tissue regeneration because they possess some advantageous properties compared to other biomaterials, including hydrogels. A variety of bio-inspired microspheres with unique structures and properties have been developed as cellular carriers and drug delivery vehicles in recent years. In this review, we provide a comprehensive summary of the progress of functional and biodegradable microspheres that have been used for tissue regeneration over the last two decades. First, we briefly introduce the biomaterials and general methods for microsphere fabrication. Next, we focus on the newly developed technologies for preparing functional microspheres, including macroporous microspheres, nanofibrous microspheres, hollow microspheres, core-shell structured microspheres, and surface-modified functional microspheres. After that, we discuss the application of functional microspheres for tissue regeneration, specifically for bone, cartilage, dental, neural, cardiac, and skin tissue regeneration. Last, we present our perspectives and future directions of functional microspheres as injectable carriers for the future advancement of tissue regeneration.

Advances in Hypoxia-Inducible Factor-1α Stabilizer Deferoxamine in Tissue Engineering.

Deferoxamine (DFO) is an iron chelator with FDA approval for the clinical treatment of iron excess. As a well-established stabilizer of hypoxia-inducible factor-1α (HIF-1α), DFO can efficiently upregulate HIF-1α and relevant downstream angiogenic factors, leading to accelerated vascularization. Moreover, as increasing studies have focused on DFO as a hypoxia-mimetic agent in recent years, it has been shown that DFO exhibited multiple functions, including stem cell regulation, immunoregulation, provascularization, and pro-osteogenesis. On the contrary, DFO can bind excess iron ions in wounds of chronic inflammation, while serving as an antioxidant with the characteristic of removing reactive oxygen species. Collectively, these characteristics make DFO a potent modulator in tissue engineering for increasing tissue integration of biomaterials in vivo and facilitating wound healing. This review outlines the activity of DFO as a representative hypoxia-mimetic agent in cells as well as the evolution of its application in tissue engineering. It can be concluded that DFO is a medication with tremendous promise and application value in future trends, which can optimize biomaterials and existing tissue engineering techniques for tissue regeneration.

Orai1 mediated store-operated calcium entry contributing to MC3T3-E1 differentiation on titanium implant with micro/nano-textured topography.

The titanium implant surface topography optimization for improving osseointegration has been performed for many years, whereas understanding the mechanisms of topography-induced osteogenic differentiation is still insufficient. In this study, the micro/nano-textured topography was created on titanium implant surface by acid etching and anodization. The MC3T3-E1 cells were incubated with different surfaces and the RNA sequencing technique was performed to obtain the transcriptomic information, which suggested the enrichment at "membrane" and "organelle" (GO) as well as "Calcium signal pathway" (KEGG). Consequently, a special attention was paid to the store-operated calcium entry (SOCE) mediated by Orai1 at ER-PM contact site. By fluorescence staining and western blot, it was confirmed that the Orai1 was upregulated on the micro/nano-textured titanium surface, which was correlated to the enhanced osteogenic differentiation induced by topography. Further experiments indicated that the CaMKII/ERK1/2 pathway was involved in. This research is the first time giving a comprehensive transcriptomic information of osteoblasts on micro/nano-textured topography and may provide deeper insight into the interaction between biomaterials and host.

Orthodontic force regulates metalloproteinase-3 promoter in osteoblasts and transgenic mouse models.

BACKGROUND/PURPOSE: Previously we demonstrated up-regulation of matrix metalloproteinase-3 (MMP-3) in human osteoblasts under compression and in bony specimens of experimental orthodontic tooth movement (OTM). Here, we studied the temporal characteristics of compression stimulation in human and mouse osteoblast cell lines, and generated a transgenic mouse model for assessing the MMP-3 expression during OTM. MATERIALS AND METHODS: We investigated MMP-3 expressions in human and murine osteoblasts through RT-PCR and luciferase assay, after compressive force loading. Inhibitors were added to identify the possible mechanisms for signal transduction. A human MMP-3 promoter was isolated, cloned and transfected to generate a transgenic mouse with a green fluorescent protein reporter. OTM was then initiated to observe the location and time course of transcriptional regulation of MMP-3 signals. RESULTS: We found changes in the transcription of MMP-3 in response to mechanical force applied to both human and mouse osteoblast cell lines, suggesting that the response is positive across species. Cloned human MMP-3 promoter may cause the response of luciferase to 1% compression. Moreover, p38 inhibitor exerted a down-regulatory effect on MMP-3 promoter expression, although the inhibitory effect didn't reach a significant level. In the transgenic mouse OTM model, we again found increased expression of MMP-3 in response to mechanical force loading around the periodontal ligament. CONCLUSION: Mechanical force can stimulate MMP-3 expression, possibly through the p38 MAPK pathway, with its strongest signal occurring at 24 h. The mechanical responsiveness in MMP-3 promoter regions can be observed in both humans and rodents in vitro and in vivo.

Osteon: Structure, Turnover, and Regeneration.

Bone is composed of dense and solid cortical bone and honeycomb-like trabecular bone. Although cortical bone provides the majority of mechanical strength for a bone, there are few studies focusing on cortical bone repair or regeneration. Osteons (the Haversian system) form structural and functional units of cortical bone. In recent years, emerging evidences have shown that the osteon structure (including osteocytes, lamellae, lacunocanalicular network, and Haversian canals) plays critical roles in bone mechanics and turnover. Therefore, reconstruction of the osteon structure is crucial for cortical bone regeneration. This article provides a systematic summary of recent advances in osteons, including the structure, function, turnover, and regenerative strategies. First, the hierarchical structure of osteons is illustrated and the critical functions of osteons in bone dynamics are introduced. Next, the modeling and remodeling processes of osteons at a cellular level and the turnover of osteons in response to mechanical loading and aging are emphasized. Furthermore, several bioengineering approaches that were recently developed to recapitulate the osteon structure are highlighted. Impact statement This review provides a comprehensive summary of recent advances in osteons, especially the roles in bone formation, remodeling, and regeneration. Besides introducing the hierarchical structure and critical functions of osteons, we elucidate the modeling and remodeling of osteons at a cellular level. Specifically, we highlight the bioengineering approaches that were recently developed to mimic the hierarchical structure of osteons. We expect that this review will provide informative insights and attract increasing attentions in orthopedic community, shedding light on cortical bone regeneration in the future.

Synbiotic Intervention with an Adlay-Based Prebiotic and Probiotics Improved Diet-Induced Metabolic Disturbance in Mice by Modulation of the Gut Microbiota.

Metabolic syndrome and its associated conditions, such as obesity and type 2 diabetes mellitus (T2DM), are a major public health issue in modern societies. Dietary interventions, including microbiota-directed foods which effectively modulate the gut microbiome, may influence the regulation of obesity and associated comorbidities. Although research on probiotics and prebiotics has been conducted extensively in recent years, diets with the use of synbiotics remain relatively unexplored. Here, we investigated the effects of a novel synbiotic intervention, consisting of an adlay seed extrusion cooked (ASEC)-based prebiotic and probiotic (Lactobacillus paracasei and Bacillus coagulans) on metabolic disorders and microbial dysbiosis in high-fat diet (HFD)-induced obese mice. The ASEC-based synbiotic intervention helped improve HFD-induced body weight gain, hyperlipidemia, impaired glucose tolerance, insulin resistance, and inflammation of the adipose and liver tissues. In addition, data from fecal metagenomics indicated that the ASEC-based synbiotic intervention fostered reconstitution of gut bacterial diversity and composition in HFD-induced obese mice. In particular, the ASEC-based synbiotic intervention increased the relative abundance of families Ruminococcaceae and Muribaculaceae and order Bacteroidales and reduced that of families Lactobacillaceae, Erysipelotrichaceae, and Streptococcaceae in HFD-induced obese mice. Collectively, our results suggest that delayed dietary intervention with the novel ASEC-based synbiotic ameliorates HFD-induced obesity, metabolic disorders, and dysbiosis.

Multifunctional polyplex micelles for efficient microRNA delivery and accelerated osteogenesis.

MicroRNAs (miRNAs) are emerging as a novel class of molecular targets and therapeutics to control gene expression for tissue repair and regeneration. However, a safe and effective transfection of miRNAs to cells has been a major barrier to their applications. In this work, a multifunctional polyplex micelle named PPP-RGI was developed as a non-viral gene vector for the efficient transfection of miR-218 (an osteogenic miRNA regulator) to bone marrow-derived mesenchymal stem cells (BMSCs) for accelerated osteogenic differentiation. PPP-RGI was designed and synthesized via conjugation of a multifunctional R9-G4-IKVAVW (RGI) peptide onto an amphiphilic poly(lactide-co-glycolide)-g-polyethylenimine-b-polyethylene glycol (PPP) copolymer. PPP-RGI self-assembled into polyplex micelles and strongly condensed miR-218 to prevent its RNase degradation. When the PPP-RGI/miR-218 complex was brought into contact with BMSCs, it exhibited high internalization efficiency and a fast escape from endo/lysosomes of the BMSCs. Subsequently, miR-218 released from the PPP-RGI/miR-218 complex regulated gene expressions and significantly enhanced the osteogenic differentiation of BMSCs. The multifunctional peptide conjugated nanocarrier serves as an effective miRNA delivery vector to promote osteogenesis.

The Role of Dental Professionals in Pandemic Events and Disaster Responses.

The past 20 years have seen major public health emergencies and natural disasters, including the Severe Acute Respiratory Syndrome outbreak caused by the SARS-associated coronavirus (SARS-CoV) in 2003; the Wenchuan earthquake in 2008; and the novel coronavirus pandemic (COVID-19) of 2019, which caused mass casualties, infections, and panic. These also resulted in complex demands for medical resources and information, and a shortage of human resources for emergency responses. To address the shortage of human resources required for these emergency responses, Chinese dental professionals made useful contributions. From this work, deficiencies in emergency response training and opportunities for the expansion of rescue capabilities were identified, and relevant recommendations made.

Nanofibrous Tubular Three-Dimensional Platform for Single Dental Pulp Stem Cell Polarization.

Dental pulp stem cells (DPSCs) are the primary stem cell source for regenerative endodontics. DPSCs need to undergo a polarization process and retain the permanent polarization status to perform the function of odontoblasts. However, the factors that control DPSC polarization and its underlying mechanism remain unknown. In this study, we established a unique nanofibrous tubular three-dimensional (3D) platform to explore DPSC polarization. The 3D platform has a "clean" background and confines one single DPSC in each microisland of the platform; therefore, it is capable of deciphering any signal that initiates or regulates DPSC polarization. Using the biomimetic platform, we identified that the nanofibrous tubular architecture is the crucial factor to initiate DPSC polarization. Dynamic morphological observation showed that the cellular process of the polarized DPSCs continuously extended and reached a plateau at 72 h. Meanwhile, Golgi apparatus, a cell polarization marker, continuously moved from a juxtanuclear region, passed the nucleus, and eventually settled down at a final position that was a few micrometers away from the nucleus. Inhibition of microfilament and microtubule polymerization demonstrated the indispensable role of cytoskeleton reorganization in modulating DPSC polarization. In addition, cell tension was involved in the regulation of DPSC polarization. The findings of this work expand the in-depth understanding of DPSC polarization, which helps design new bioinspired materials for regenerative endodontics.

Precautions in dentistry against the outbreak of corona virus disease 2019.

The outbreak of Coronavirus Disease 2019 (COVID-19) has become a severe global acute respiratory pandemic around the world in just a few months with an increasing number of infections and deaths. COVID-19 is a highly contagious and fatal disease. Almost everyone in the population is susceptible, and the incubation period is 1-14 days, mostly 3-7 days. The clinical symptoms of the COVID-19 are fever, dry cough and fatigue. Some patients are accompanied by symptoms such as nasal congestion, runny nose, sore throat, myalgia and diarrhea. Severe patients could even develop acute respiratory distress syndrome, septic shocks, metabolic acidosis and multifunctional organ failure, etc. Due to the relatively closed environment of dental clinics and the unique nature of dental procedures, both dental personnel and patients are easy to get infection through currently known respiratory droplet transmission, aerosol transmission, close contact transmission and other ways, inducing mutual cross-infection. Dental practitioners are facing unprecedented challenges due to the high risk of exposure to droplets and aerosols from saliva and other body fluids during dental procedures. Based on our experience and relevant research, this article introduces the basic knowledge about COVID-19 and the corresponding protective measures for dental practitioners, includes the risk of infection during dental procedures, the precautions related to the patients, infection control measures during dental treatment in clinics, protection measures at different levels for dental practitioners, and emergency dental treatment for confirmed COVID-19. It is the responsibility of every dental practitioner to fully understand the characteristics of the new coronavirus and strictly implement the most appropriate protective measures to reduce and control the risk of cross infection in dental procedures.

Quantitative characterizations of the Sharpey's fibers of rat molars.

BACKGROUND AND OBJECTIVE: The Sharpey's fibers of periodontal ligament (PDL) anchor the PDL to alveolar bone and cementum and are essential for the function of PDL. While qualitative analyses of the Sharpey's fibers have been widely explored, a comprehensive quantitative characterization of the Sharpey's fibers is not available. In this work, we selected rat molars as a model and comprehensively characterized the PDL Sharpey's fibers (diameter, density, length, embedding angle, and insertion angle). MATERIALS AND METHODS: A total of 24 rat mandibular molars, eight maxillary first molars, and their surrounding alveolar bone were harvested, fixed, rendered anorganic and observed under scanning electron microscopy (SEM). The mandibles and maxillae (n = 4) were harvested, processed, sectioned, and stained with Sirius red for histological observation. SEM images were used for quantitative analyses of diameters and densities of the Sharpey's fibers, while Sirius red staining images were used to measure lengths and angles. The Sharpey's fibers were comprehensively characterized in terms of positions (cervical, middle, and apical thirds), PDL fiber groups (alveolar crest, horizontal, oblique, apical, and interradicular groups), sides (cementum and bone sides), and teeth (mandibular first, second, third molars, and maxillary first molar). RESULTS: Our results showed that the characteristic parameters of the Sharpey's fibers varied in different positions, fiber groups, sides, and teeth. Specifically, the median diameter of the Sharpey's fibers on the bone side was significantly greater than that on the cementum side, while the median density of the Sharpey's fibers on the bone side was significantly lower than that on the cementum side, regardless of the positions and teeth. For the same tooth, the median length of the embedded Sharpey's fibers on the bone side was more than two times greater than that on the cementum side. Among all fiber groups, the alveolar crest group had the maximum length of the Sharpey's fibers on the bone side and the minimal length of the Sharpey's fibers on the cementum side. There is an approximate 5-15° difference between the embedding angle and the insertion angle in each group. The oblique group had the smallest embedding angles on both the bone and cementum sides. CONCLUSION: This study provides a comprehensive and quantitative characterization of the Sharpey's fibers using rat molars as a model. Overall, these parameters varied according to different vertical positions, fiber groups, teeth, and jawbones. The quantitative information of the Sharpey's fibers presented in this work facilitates our understanding of PDL functions and advances the development of biomimetic materials for periodontal tissue regeneration.

Antiplatelet, antioxidative, and anti-inflammatory effects of hydroquinone.

Platelets play crucial roles in thrombosis and hemostasis through platelet activation and aggregation that are crucial in cardiovascular diseases. Hydroquinone (HQ) and its derivatives are present in many dermatological creams, paints, motor fuels, air, microorganisms, and plant products like wheat bread, fruit, coffee, and red wine. The effect of HQ on humans is not clear. In this study, we found that HQ (>25 µM) inhibited arachidonic acid (AA)-induced platelet aggregation. HQ suppressed AA-induced thromboxane B2 production of platelets. HQ (>10 µM) also attenuated ex vivo platelet-rich plasma aggregation. HQ prevented the interleukin (IL)-1ß-induced 8-isoprostane, and PGE2 production, but not IL-8 production of pulp cells. These results indicate that HQ may have an antiplatelet effect via inhibition of thromboxane production. HQ has antioxidative and anti-inflammatory effects, and possible inhibition of COX. Exposure and consumption of HQ-containing products, food or drugs may have antiplatelet, antioxidative, and anti-inflammatory effects.

Cell polarization: From epithelial cells to odontoblasts.

Cell polarity identifies the asymmetry of a cell. Various types of cells, including odontoblasts and epithelial cells, polarize to fulfil their destined functions. Odontoblast polarization is a prerequisite and fundamental step for tooth development and tubular dentin formation. Current knowledge of odontoblast polarization, however, is very limited, which greatly impedes the development of novel approaches for regenerative endodontics. Compared to odontoblasts, epithelial cell polarization has been extensively studied over the last several decades. The knowledge obtained from epithelia polarization has been found applicable to other cell types, which is particularly useful considering the remarkable similarities of the morphological and compositional features between polarized odontoblasts and epithelia. In this review, we first discuss the characteristics, the key regulatory factors, and the process of epithelial polarity. Next, we compare the known facts of odontoblast polarization with epithelial cells. Lastly, we clarify knowledge gaps in odontoblast polarization and propose the directions for future research to fill the gaps, leading to the advancement of regenerative endodontics.