Profiled polyethylene terephthalate filaments that incorporate collagen and calcium phosphate enhance ligamentisation and bone formation.

Polyethylene terephthalate (PET) artificial ligaments offer an unlimited source of ligaments without donor-site-related morbidity and with good mechanical properties for a rapid return to sporting activities. Developing PET artificial ligaments with excellent ligamentisation and ligament-bone healing is still a considerable challenge. This study aimed to investigate the effects of the profiled PET/collagen/calcium phosphate (PET/C/CaP) ligament upon cell growth, ligamentisation and ligament-bone healing in vitro and in vivo. Profiled PET/C/CaP filaments were made by melt-spinning process with 2 % CaP hybrid spinning and collagen coating. Rat mesenchymal stem cells (MSCs) were cultured on the profiled PET/C filaments for cytotoxicity, viability, scanning electron microscopy (SEM) and ligament-related gene expression analysis. MSCs' osteogenic capacity on the profiled PET/CaP filaments was identified by detecting osteogenic gene expression and alizarin red S staining. For in vivo verification, an animal study was performed to evaluate the effect of the profiled PET/C/CaP ligament in a rabbit knee medial collateral ligament reinforcement reconstruction model. The graft ligamentisation and bone formation were investigated by SEM, histology, microcomputed tomography and mechanical tests. The profiled PET/C filaments enhanced MSC proliferation and ligament-related gene expression. Furthermore, they enhanced osteogenic gene expression, alkaline phosphatase activity and mineralisation of MSCs. The in vivo study indicated that the profiled PET/C/CaP ligament enhanced ligamentous matrix remodelling and bone formation. Therefore, their use is an effective strategy for promoting MSCs' ligamentous and osteogenic potential in vitro and enhancing ligamentous matrix remodelling and bone formation in vivo.

Retrospective analysis of the association between tooth loss and dementia: a population-based matched case-control study.

OBJECTIVE: To clarify the association between multiple tooth loss and dementia. BASIC RESEARCH DESIGN: Case-control study based on the claims data from National Health Insurance Research Database (NHIRD). Patients were divided into two groups: the dementia groups and non-dementia group. For each case patient, one control patient was randomly selected and frequency matched by age (per 5 years) and sex. The case group comprised patients newly diagnosed with dementia, and the index date was the the date of dementia diagnosis, which became the baseline for comorbidity and age calculations. RESULTS: Among the 43,026 individuals, patients with dementia had a significantly higher extraction density at ages 60-69 (p ⟨ 0.0001) and 70-79 (p = 0.04) years compared with control patients. CONCLUSIONS: This population-based retrospective study demonstrated an association between tooth loss and dementia. Patients in Taiwan with more tooth extraction experience are likely to have an increased risk of dementia.

Lower dietary fibre intake, but not total water consumption, is associated with constipation: a population-based analysis.

BACKGROUND: Associations between constipation and dietary fibre and water intake, as well as various lifestyle factors, have not been fully evaluated. The present study aimed to investigate associations between fibre and water intake and constipation, as well as other possible risk factors for constipation, in a large adult population. METHODS: Data obtained from 14 024 adults aged ≥20 years from three cycles of the National Health and Nutrition Examination Survey (NHANES) 2005-2010, who had completed a bowel health questionnaire, were included in this cross-sectional population-based study. Variables included demographics, lifestyle and dietary factors, comorbidities and laboratory parameters. Logistic regression analyses were performed to determine associations between potential risk factors and constipation. RESULTS: Among 17 132 participants ≥20 years, 2401 (14%) did not complete bowel health questionnaires and were excluded, along with pregnant women (n = 461) and participants without dietary sample weight on day 1 (n = 246), leaving data from 14 024 participants available for analysis. Multivariate analysis revealed that black race/ethnicity [odds ratio (OR) = 1.380, 95% confidence interval (CI) = 1.054-1.809], a lower than 12th grade education (OR = 1.420, 95% CI = 1.154-1.749) or high school education (OR = 1.339, 95% CI = 1.057-1.697), lower income/poverty ratios (1.3-3.49 versus ≥3.5: OR = 1.261, 95% CI = 1.015-1.567), normal weight (OR = 1.913, 95% CI = 1.534-2.386) or overweight (OR = 1.536, 95% CI = 1.207-1.955), depression (OR = 1.610, 95% CI = 1.119-2.315) and poor teeth (OR = 1.441, 95% CI = 1.100-1.888) were associated with an increased risk for constipation. Lower dietary fibre intake was associated with a greater risk of constipation. Total water consumption was significantly associated an with an increased risk of constipation in univariate analysis, but not in multivariate analysis. CONCLUSIONS: Lower dietary fibre intake, but not poor water consumption, was associated with a greater risk of constipation in US adults.

Pharyngeal airway changes following maxillary expansion or protraction: A meta-analysis.

The aim of this meta-analysis was to investigate the changes in airway dimensions after rapid maxillary expansion (RME) and facemask (FM) protraction. Using PubMed, Medline, ScienceDirect and Web of Science, only controlled clinical trials, published up to November 2016, with RME and/or FM as keywords that had ≥6 months follow-up period were included in this meta-analysis. The changes in pharyngeal airway dimension in both two-dimensional and three-dimensional images were included in the analysis. Nine studies met the criteria. There are statically significant changes in upper airway and nasal passage airway in the intervention groups as compared to the control groups, assessed in two-dimensional and three-dimensional images. However , in the lower airway and the airway below the palatal plane, no statistically significant changes are seen in 2D and 3D images. RME/FM treatments might increase the upper airway space in children and young adolescents. However, more RCTs and long-term cohort studies are needed to further clarify the effects on pharyngeal airway changes.

The roles of autophagy and hypoxia in human inflammatory periapical lesions.

AIM: To determine the expressions of hypoxia-related [hypoxia-inducible transcription factors (HIF)-1α, BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3) and phospho-adenosine monophosphate activated protein kinase (pAMPK)] and autophagy-related [microtubule-associated protein 1 light chain 3 (LC3), beclin-1 (BECN-1), autophagy-related gene (Atg)5-12, and p62] proteins in human inflammatory periapical lesions. METHODOLOGY: Fifteen samples of radicular cysts (RCs) and 21 periapical granulomas (PGs), combined with 17 healthy dental pulp tissues, were examined. Enzyme-linked immunosorbent assay (ELISA) was used to detect interleukin (IL)-1ß cytokine; immunohistochemical (IHC) and Western blot (WB) analyses were employed to examine autophagy-related and hypoxia-related proteins. Transmission electron microscopy (TEM) was used to explore the ultrastructural morphology of autophagy in periapical lesions. Nonparametric Kruskal-Wallis tests and Mann-Whitney U-tests were used for statistical analyses. RESULTS: ELISA revealed a significantly higher (P < 0.001) IL-1ß expression in periapical lesions than in normal pulp tissue. Immunoscores of IHC expressions of pAMPK, HIF-1α, BNIP3, BECN-1 and Atg5-12 proteins in periapical lesions were significantly higher (P < 0.001) (except BECN-1) than those in normal pulp tissue. The results of IHC studies were largely compatible with those of WB analyses, where significantly higher (P < 0.05) expressions of hypoxia-related and autophagy-related proteins (except BECN-1, p62 and LC3II in WB analyses) in periapical lesions were noted as compared to normal pulp tissue. Upon TEM, ultrastructural double-membrane autophagosomes and autolysosomes were observed in PGs and RCs. CONCLUSIONS: Autophagy associated with hypoxia may play a potential causative role in the development and maintenance of inflamed periapical lesions.

[Efficacy and mechanism of local delivery of rapamycin and rapamycin-loaded poly(lactic-co-glycolic) acid nanoparticles on coronary restenosis of injury-stenosis model of minipigs].

OBJECTIVE: To determine whether intramural administration of rapamycin (RPM)-loaded polylactic-polyglycolic acid (PLGA) nanoparticles (NPs) can reduce intimal thickening and affect the mRNA expressions of matrix metalloproteinase (MMP)-2, tissue inhibitor of metalloproteinase (TIMP)-2 and p27(kipl) in a coronary injury-stenosis model of minipigs. METHODS: Twenty eight minipigs were randomly separated into four groups: saline group (n=7), blank PLGA NPs group (5.0 mg/ml)(n=7), RPM group (1.0 mg/ml)(n=7), and RPM-PLGA NPs(5.0 mg/ml)group (n=7), respectively. Different treatments were intracoronary locally delivered via a Dispatch™ catheter for 10 minutes. Serial angiography was performed pre-and post-modeling 30 days and the percent stenosis degree was assessed. Hematoxylin-Eosin (HE) staining, Weigert's resorcin fuchsin staining and picric acid-sirius red staining were used for morphometric analysis. Immunohistochemistry was performed to assess the levels of proliferating cell nuclear antigen (PCNA), MMP-2, and TIMP-2 at early and late time points, respectively. The expression of p27(kip1) mRNA was detected by in situ hybridization staining. RESULTS: Data from 21 minipigs had been collected at the end of the experiment with 6, 4, 5, and 6 from the former mentioned 4 groups, respectively. For the instant injury index, there was no significant difference among the four groups. The percent stenosis degree of RPM-PLGA NPs group was significantly lower than that of the other three groups respectively (all P< 0.05). The neointima area, net external elastic lamina area to external elastic laminal area ratio, and proliferative index of RPM-PLGA NPs group were significantly less than those of the other three groups, with all the P values less than 0.05. The mean value of integral optical density of p27(kip1)mRNA expression of RPM-PLGA group was 0.35 ± 0.06, higher than that of blank PLGA NPs group (0.12 ± 0.05, P< 0.01), saline group (0.16 ± 0.03, P< 0.05), and RPM group (0.15 ± 0.03, P< 0.05), respectively. The MMP-2/TIMP-2 ratio and the positive expression index of PCNA in RPM-PLGA group were lower than that of the other groups (P< 0.05). CONCLUSIONS: Locally delivered rapamycin-loaded PLGA NPs significantly reduces MMP-2/TIMP-2 ratio and PCNA expression, increases p27(kip1) mRNA expression and significantly relieves percent stenosis degree and shows excellent acute procedural results in the minipig interventional coronary artery oversized balloon injury model. The results from minipig model further support that this approach could be a potential clinical procedure for vascular proliferative disease.

Differential Gene Expression Profiles Reflecting Macrophage Polarization in Aging and Periodontitis Gingival Tissues.

Recent evidence has determined a phenotypic and functional heterogeneity for macrophage populations. This plasticity of macrophage function has been related to specific properties of subsets (M1 and M2) of these cells in inflammation, adaptive immune responses and resolution of tissue destructive processes. This investigation hypothesized that targeted alterations in the distribution of macrophage phenotypes in aged individuals, and with periodontitis would be skewed towards M1 inflammatory macrophages in gingival tissues. The study used a non-human primate model to evaluate gene expression profiles as footprints of macrophage variation in healthy and periodontitis gingival tissues from animals 3-23 years of age and in periodontitis tissues in adult and aged animals. Significant increases in multiple genes reflecting overall increases in macrophage activities were observed in healthy aged tissues, and were significantly increased in periodontitis tissues from both adults and aged animals. Generally, gene expression patterns for M2 macrophages were similar in healthy young, adolescent and adult tissues. However, modest increases were noted in healthy aged tissues, similar to those seen in periodontitis tissues from both age groups. M1 macrophage gene transcription patterns increased significantly over the age range in healthy tissues, with multiple genes (e.g. CCL13, CCL19, CCR7 and TLR4) significantly increased in aged animals. Additionally, gene expression patterns for M1 macrophages were significantly increased in adult health versus periodontitis and aged healthy versus periodontitis. The findings supported a significant increase in macrophages with aging and in periodontitis. The primary increases in both healthy aged tissues and, particularly periodontitis tissues appeared in the M1 phenotype.

Evaluating the possibility of using acetone-butanol-ethanol (ABE) fermentation wastewater for bacterial cellulose production by Gluconacetobacter xylinus.

UNLABELLED: To reduce the cost of bacterial cellulose (BC) production, the possibility of using acetone-butanol-ethanol (ABE) fermentation wastewater with high COD value (18 050 mg l(-1) ) for BC production by Gluconacetobacter xylinus was evaluated. After 7 days of fermentation, the highest BC yield (1·34 g l(-1) ) was obtained. The carbon sources including sugars (glucose and xylose), organic acids (acetic acid and butyric acid) and alcohol compounds (ethanol and butanol) were utilized by G. xylinus simultaneously during fermentation. Although the COD decrease ratio (about 14·7%) was low, the highest BC yield on COD consumption (56·2%, g g(-1) ) was relatively high and the remaining wastewater could be used for further BC fermentation. Besides, the environment of ABE fermentation wastewater showed small influence on the BC structure by comparison with the BC products obtained in traditional HS medium using field emission scanning electron microscope (FE-SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Overall, ABE fermentation wastewater is one promising substrate for BC production. SIGNIFICANCE AND IMPACT OF THE STUDY: The possibility of using acetone-butanol-ethanol (ABE) fermentation wastewater for bacterial cellulose (BC) production by Gluconacetobacter xylinus was evaluated in this study. This is the first time that ABE fermentation wastewater was used as substrate for BC fermentation. The results provide detail information of metabolism of G. xylinus in ABE fermentation wastewater and the influence of wastewater environment on the structure of BC samples. Overall, this bioconversion could reduce the cost of BC production greatly.

Clinical analysis of submucosal Medpor implantation for empty nose syndrome.

BACKGROUND: Empty nose syndrome (ENS) describes symptomatology and radiographic findings after surgeries on turbinates.The treatment of ENS is still debatable. PURPOSE: To analyse clinical outcomes of submucosal Medpor® implantation for ENS. METHODS: A total of 18 patients underwent submucosal Medpor® implantation from 2006 to 2011. We applied SNOT-22 (SinoNasalOutcome Test) for statistical survey of the patients' symptoms before and after surgery. RESULTS: Two patients were lost to follow up after the surgery. Most of the patients developed ENS-related symptoms gradually within 2 years to 16 years after the previous nasal surgery or treatment. The sites of submucosal implantation are mainly septum and nasal floor, unilaterally or bilaterally. There is a significant improvement of SNOT-22 pre-operatively to one year post-operatively. CONCLUSIONS: The symptomatolgy remains the most important point when dealing with patients with ENS. Submucosal implantation of Medpor® is a feasible surgical treatment to ENS. A positive cotton test is suggested for the surgical indication and planning.

Rapid Intrafibrillar Mineralization Strategy Enhances Adhesive-Dentin Interface.

Biomimetic mineralization of dentin collagen appears to be a promising strategy to optimize dentin bonding durability. However, traditional postbonding mineralization strategies based on Ca/P ion release still have some drawbacks, such as being time-consuming, having a spatiotemporal mismatch, and having limited intrafibrillar minerals. To tackle these problems, a prebonding rapid intrafibrillar mineralization strategy was developed in the present study. Specifically, polyacrylic acid-stabilized amorphous calcium fluoride (PAA-ACF) was found to induce rapid intrafibrillar mineralization of the single-layer collagen model and dentin collagen at just 1 min and 10 min, as identified by transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. This strategy has also been identified to strengthen the mechanical properties of demineralized dentin within a clinically acceptable timeframe. Significantly, the bonding strength of the PAA-ACF-treated groups outperformed the control group irrespective of aging modes. In addition, the endogenous matrix metalloproteinases as well as exogenous bacterial erosion were inhibited, thus reducing the degradation of dentin collagen. High-quality integration of the hybrid layer and the underlying dentin was also demonstrated. On the basis of the present results, the concept of "prebonding rapid intrafibrillar mineralization" was proposed. This user-friendly scheme introduced PAA-ACF-based intrafibrillar mineralization into dentin bonding for the first time. As multifunctional primers, PAA-ACF precursors have the potential to shed new light on prolonging the service life of adhesive restorations, with promising significance.

[A two-dimensional photographic and three-dimensional digital dental model comparative analysis in maxillary anterior teeth].

Objective: To assess the accuracy of two-dimensional (2D) photographs in measuring esthetic parameters of the maxillary anterior teeth by comparing them with measurements obtained from three-dimensional (3D) dental models. Methods: A total of one hundred volunteers (49 males, 51 females, aged 18-23 years) were recruited from School and Hospital of Stomatology, Wuhan University from January to February 2024. 3D digital models of their dentitions were obtained using an intraoral scanner, and standardized frontal 2D intraoral photographs were captured with a digital camera. The lengths, widths and width/length ratio of the bilateral incisors, lateral incisors and canines were measured on both the 3D digital models and the 2D intraoral photographs. The width ratios of adjacent maxillary anterior were also calculated on the 2D intraoral photographs and the frontal view of 3D digital models. Results: The widths of lateral incisors [(5.85±0.60) mm] and canines [(4.73±0.71) mm] and the lengths of canines [(8.72±0.96) mm] in the 2D intraoral photographs were significantly lower than those in 3D digital models [(6.65±0.59), (7.76±0.60), (8.90±0.86) mm] (t=-18.24, P<0.001; t=-54.43, P<0.001; t=-4.40, P<0.001), while there were no significant differences in the lengths and widths of the other teeth (P>0.05). The width/length ratios measured from the 2D intraoral photographs for the lateral incisors and canines (0.74±0.08, 0.55±0.08) were significantly lower than those measured in the 3D digital models (0.84±0.09, 0.88±0.09) (t=-19.68, P<0.001; t=-50.21, P<0.001), and the width/length ratio of the central incisors showed no significant difference between the two groups (P>0.05). The width ratios of canines/lateral incisors and lateral incisors/central incisors measured on the 2D intraoral photographs (0.72±0.06, 0.85±0.11) were significantly smaller than those measured in the frontal view of 3D digital models (0.75±0.06, 0.89±0.11) (t=-9.31, P<0.001; t=-6.58, P<0.001). Conclusions: There is a difference between 2D and 3D measurement results of teeth in the esthetic area and the magnitude of the difference varies with their position in the dental arch. When analyzing the measurement of the anterior teeth, it is necessary to choose the appropriate method according to the target tooth position.

Butyrate induces reactive oxygen species production and affects cell cycle progression in human gingival fibroblasts.

BACKGROUND AND OBJECTIVE: Short-chain fatty acids, such as butyric acid and propionic acid, are metabolic by-products generated by periodontal microflora such as Porphyromonas gingivalis, and contribute to the pathogenesis of periodontitis. However, the effects of butyrate on the biological activities of gingival fibroblasts (GFs) are not well elucidated. MATERIAL AND METHODS: Human GFs were exposed to various concentrations of butyrate (0.5-16 mm) for 24 h. Viable cells that excluded trypan blue were counted. Cell cycle distribution of GFs was analyzed by propidium iodide-staining flow cytometry. Cellular reactive oxygen species (ROS) production was measured by flow cytometry using 2',7'-dichlorofluorescein (DCF). Total RNA and protein lysates were isolated and subjected to RT-PCR using specific primers or to western blotting using specific antibodies, respectively. RESULTS: Butyrate inhibited the growth of GFs, as indicated by a decrease in the number of viable cells. This event was associated with an induction of G0/G1 and G2/M cell cycle arrest by butyrate (4-16 mm) in GFs. However, no marked apoptosis of GFs was noted in this experimental condition. Butyrate (> 2 mm) inhibited the expression of cdc2, cdc25C and cyclinB1 mRNAs and reduced the levels of Cdc2, Cdc25C and cyclinB1 proteins in GFs, as determined using RT-PCR and western blotting, respectively. This toxic effect of butyrate was associated with the production of ROS. CONCLUSION: These results suggest that butyrate generated by periodontal pathogens may be involved in the pathogenesis of periodontal diseases via the induction of ROS production and the impairment of cell growth, cell cycle progression and expression of cell cycle-related genes in GFs. These events are important in the initiation and prolongation of inflammatory processes in periodontal diseases.

Bioconversion of elephant grass (Pennisetum purpureum) acid hydrolysate to bacterial cellulose by Gluconacetobacter xylinus.

AIMS: To evaluate the possibility of elephant grass acid hydrolysate converting into bacterial cellulose (BC) produced by Gluconacetobacter xylinus CH001 and to characterize the morphology and structure of the cellulose produced. METHODS AND RESULTS: Acid-hydrolysed and detoxified elephant grass acid hydrolysate was inoculated with G. xylinus CH001. After 14 days of static fermentation, about 6·4 g l(-1) of BC could be generated. Meanwhile, 60·4% (w/w) of BC yield on sugar consumption was obtained. Scanning electron micrographs illustrated that the network of cellulose fibres became denser, and the diameter changed with the growth. FT-IR spectra showed almost same results for all the BC samples collected on different culture time. X-ray diffractograms demonstrated that the crystalline form of BC was cellulose I, the crystallinity increased to 53·58%, and the crystallinity index reached up to 99%. CONCLUSIONS: Elephant grass acid hydrolysate could be utilized efficiently for BC production by G. xylinus CH001. Structure analysis on the cellulose produced showed its potential of being excellent material for further application. SIGNIFICANCE AND IMPACT OF THE STUDY: Our studies for the first time examined the bioconversion of low-cost elephant grass into high-value BC and the changes in its morphology and structure following the culture time.

Thermal response of a dental tissue induced by femtosecond laser pulses.

This paper reports a theoretical and experimental study for thermal transport in a thin slice of human tooth induced by a 120 fs, 800 nm pulse laser at a repetition rate of 1 kHz. The surface reflectivity of enamel and the convection heat transfer coefficient were determined using an inverse heat transfer analysis. Instead of a fully three-dimensional modeling, two simplified two-dimensional (2D) planar and axisymmetric heat conduction models were proposed to simulate the temperature fields. The temperature responses obtained from the 2D planar and axisymmetric model agree well with the experimental measurements. On the other hand, the one-dimensional (1D) result significantly differs from the 2D axisymmetric one, suggesting that care should be taken when a 1D thermal model is considered for estimating temperature response.

A fractal dimensional approach to successful evaluation of apical healing.

AIM: To evaluate whether the initial healing of apical radiolucencies 1 year after root canal treatment could be quantitatively identified by the change in fractal dimension (FD) values for the eventually completely healed cases. METHODOLOGY: Twenty-six patients with successful root canal treatment were recruited. All teeth were associated with complete healing either before or at 1 year following treatment (six of 26) or still undergoing healing at 1 year after treatment but completely healed thereafter (20 of 26). Two radiographs were selected for the same patient, one taken before treatment and the other taken 1 year after treatment. Eight regions of interests (ROIs) were selected from each radiograph, two as the experimental group located close to the infected root apex, two as the control group in the healthy bone and the other four in the healthy bone ensuring the image quality. RESULTS: Based on the FD values of the four ROIs in the healthy bone, the two radiographs were confirmed to have been taken with similar projection angles and exposure. The FD values were shown to significantly increase (P = 0.006) and decrease (P = 0.000) around the root apex and the neighbouring region of the apical lesion, respectively. CONCLUSION: Changes in fractal dimension values may serve as a necessary condition to quantitatively indicate the initial healing status 1 year after root canal treatment.

[Establishment and clinical practice of the global diagnostic and theraputic concept of dental esthetic restoration].

Dental esthetic restoration covers from facial esthetics to dental esthetics, from the realization of macroscopic to microscopic esthetic restoration goals. As an esthetic restorative dentist, he has to face and solve the increasingly high diagnosis and treatment needs of patients, the increasingly standardized needs of the dental industry, and the need for oral health to become an important part of the Healthy China strategy. Dentists engaged in esthetic restoration field should establish a concept and practice system of global esthetic restoration centered on esthetic diagnosis, interdisciplinary esthetic restoration as a means, and characterized by fine microscopic restoration. Dental esthetic restoration dentists should be the designer of esthetic restoration plans and treatment plans, as well as the implementers of the final esthetic effect. Dentists should accurately grasp the global diagnosis concept and practice system of esthetic restoration, and provide standardized and high-quality oral diagnosis and treatment services for more patients.

The Application of Organs-on-a-Chip in Dental, Oral, and Craniofacial Research.

The current development of microfluidics-based microphysiological systems (MPSs) will rapidly lead to a paradigm shift from traditional static 2-dimensional cell cultivation towards organized tissue culture within a dynamic cellular milieu. Especially organs-on-a-chip (OoCs) can very precisely re-create the mechanical and unique anatomical structures of the oral environment. This review provides an introduction to such technology, from commonly used chip materials and fabrication methods to the application of OoC in in vitro culture. OoCs are advantageous because of their small-scaled culture environment, the highly controlled dynamic experimental conditions, and the likeness to the in vivo structure. We specifically focus on current chip designs in dental, oral, and craniofacial (DOC) research. Also, future perspectives are discussed, like model standardization and the development of integrated platforms with advanced read-out functionality. By doing so, it will be possible for OoCs to serve as an alternative for animal testing and to develop highly predictive human models for clinical experiments and even personalized medicine.

Advances in tooth agenesis and tooth regeneration.

The lack of treatment options for congenital (0.1%) and partial (10%) tooth anomalies highlights the need to develop innovative strategies. Over two decades of dedicated research have led to breakthroughs in the treatment of congenital and acquired tooth loss. We revealed that by inactivating USAG-1, congenital tooth agenesis can be successfully ameliorated during early tooth development and that the inactivation promotes late-stage tooth morphogenesis in double knockout mice. Furthermore, Anti- USAG-1 antibody treatment in mice is effective in tooth regeneration and can be a breakthrough in treating tooth anomalies in humans. With approximately 0.1% of the population suffering from congenital tooth agenesis and 10% of children worldwide suffering from partial tooth loss, early diagnosis will improve outcomes and the quality of life of patients. Understanding the role of pathogenic USAG-1 variants, their interacting gene partners, and their protein functions will help develop critical biomarkers. Advances in next-generation sequencing, mass spectrometry, and imaging technologies will assist in developing companion and predictive biomarkers to help identify patients who will benefit from tooth regeneration.

Effect of intracanal dentine wettability on human dental pulp cell attachment.

AIM: To evaluate the effect of intracanal dentine wettability on human dental pulp cell (HDPC) attachment after application of endodontic irrigants. METHODOLOGY: Twenty extracted human premolar teeth with straight canals were sectioned at the apical and coronal thirds of each root, and the remaining mid-root portions were bisected longitudinally. After polishing, the specimens were divided into two groups for wettability and cell attachment measurements, respectively. The intracanal surface wettability was assessed by atomic force microscopy after a rinse of H(2) O (control), 5.25% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid (EDTA) and MTAD (n = 5). Additionally, HDPCs were seeded onto the irrigated root canal dentine and the cell attachment was evaluated by calcein-CAM and propidium iodide (PI) dying under fluorescence microscope (n = 5). Data were analysed by means of one-way anova and LSD test. RESULTS: Compared with the control group, 5.25% NaOCl, 17% EDTA and MTAD treatment significantly increased surface wettability (P < 0.001). The rank order of adhesion force was MTAD >17% EDTA >5.25% NaOCl > H(2) O. The highest average numbers of viable HDPCs were observed on the root canals irrigated with MTAD, followed by the 17% EDTA group (P < 0.001), and the lowest average numbers of viable cells were detected in the 5.25% NaOCl and H(2) O groups. CONCLUSIONS: Surface wettability was affected by the irrigants. Increasing in wettability produced higher levels of HDPC attachment to irrigated dentine.

Pcsk9 Knockout Aggravated Experimental Apical Periodontitis via LDLR.

Apical periodontitis (AP), an inflammatory lesion around the apex of tooth roots, is mostly caused by dental pulp infection. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a vital role in regulating cholesterol homeostasis by targeting low-density lipoprotein receptor (LDLR) and participates in bacterium-induced chronic periodontitis. However, the roles of PCSK9 in AP are unknown. Here, we investigated its role in AP by using Pcsk9-/- mice. Micro-computed tomography scanning and histological staining revealed that the periapical bone loss of Pcsk9-/- mice was greater than that of wild-type (WT) mice, and increased expression of inflammation-related factors tumor necrosis factor α (TNF-α) and interleukin (IL)-6 was also observed. Immunofluorescence staining and quantitative real-time polymerase chain reaction showed PCSK9 expression in bone marrow macrophages (BMMs) was increased after treatment with lipopolysaccharide (LPS). This finding was consistent with the in vivo results that the expression level of PCSK9 in exposed WT mice increased compared with that in unexposed WT mice. After LPS challenge, the expression levels of TNF-α, IL-1ß, and IL-6 in BMMs were increased, and Pcsk9 knockout aggravated the expression of these inflammatory factors. The number of osteoclasts positive for tartrate-resistant acid phosphatase staining around the apical lesion in Pcsk9-/- mice was higher than that in WT mice. Then BMMs underwent the osteoclast differentiation. Pcsk9 knockout BMMs induced increased and larger osteoclasts. While this effect of Pcsk9 knockout was abolished by the addition of Ldlr small interfering RNA, revealing that Pcsk9 knockout increased osteoclastogenesis was dependent on the LDLR. Immunohistochemistry staining showed increased expression level of LDLR in exposed Pcsk9-/- periapical areas. In vitro experiments showed that LPS promoted the expression level of LDLR in Pcsk9-/- BMMs and increased osteoclast formation ability, indicating that LPS promoted the elevation of osteoclasteogenesis caused by the Pcsk9 knockout. In conclusion, Pcsk9 deficiency aggravated the inflammatory response and promoted the osteoclastogenesis in an LDLR-dependent manner in AP experimental mice.