Apical microsurgery is accurate and minimally invasive, produces few complications, and has a success rate of more than 90%. However, due to the lack of awareness and understanding of apical microsurgery by dental general practitioners and even endodontists, many clinical problems remain to be overcome. The consensus has gathered well-known domestic experts to hold a series of special discussions and reached the consensus. This document specifies the indications, contraindications, preoperative preparations, operational procedures, complication prevention measures, and efficacy evaluation of apical microsurgery and is applicable to dentists who perform apical microsurgery after systematic training.
Microsurgery/standards* ; Humans ; Apicoectomy ; Contraindications, Procedure ; Tooth Apex/diagnostic imaging* ; Postoperative Complications/prevention & control* ; Consensus ; Treatment Outcome

Approximately 20% to 30% of the global workforce is engaged in shift work. As a significant cause of circadian disruption, shift work is closely associated with an increased risk for periodontitis. Nevertheless, how shift work-related circadian disruption functions in periodontitis remains unknown. Herein, we employed a simulated shift work model constructed by controlling the environmental light-dark cycles and revealed that shift work-related circadian disruption exacerbated the progression of experimental periodontitis. RNA sequencing and in vitro experiments indicated that downregulation of the core circadian protein brain and muscle ARNT-like protein 1 (BMAL1) and activation of the Gasdermin D (GSDMD)-mediated pyroptosis were involved in the pathogenesis of that. Mechanically, BMAL1 regulated GSDMD-mediated pyroptosis by suppressing NOD-like receptor protein 3 (NLRP3) inflammasome signaling through modulating nuclear receptor subfamily 1 group D member 1 (NR1D1), and inhibiting Gsdmd transcription via directly binding to the E-box elements in its promoter. GSDMD-mediated pyroptosis accelerated periodontitis progression, whereas downregulated BMAL1 under circadian disruption further aggravated periodontal destruction by increasing GSDMD activity. And restoring the level of BMAL1 by circadian recovery and SR8278 injection alleviated simulated shift work-exacerbated periodontitis via lessening GSDMD-mediated pyroptosis. These findings provide new evidence and potential interventional targets for circadian disruption-accelerated periodontitis.
Pyroptosis/physiology* ; ARNTL Transcription Factors/metabolism* ; Animals ; Periodontitis/etiology* ; Mice ; Phosphate-Binding Proteins/metabolism* ; Shift Work Schedule/adverse effects* ; Intracellular Signaling Peptides and Proteins/metabolism* ; Mice, Inbred C57BL ; Male ; Disease Models, Animal ; Gasdermins

Objective:To observe whether endothelial cells undergo pyroptosis in the inflammatory periodontal environment by using a model in vivo and in vitro, providing an experimental basis for indepth understanding of the underlying pathogenesis of periodontitis. Methods:According to the classification of periodontal diseases of 2018, gingival tissues were collected from periodontally healthy subjects and patients with stage Ⅲ-Ⅳ, grade C periodontitis, who presented Department of Oral and Maxillofacial Surgery and Department of Periodontology, School of Stomatology, The Fourth Military Medical University from April to May 2022. Immunohistochemical staining was performed to detect the expression level and distribution of gasdermin D (GSDMD), a hallmark protein of cell pyroptosis, in gingival tissues. Periodontitis models were established in each group by ligating the maxillary second molar teeth of three mice for 2 weeks (ligation group). The alveolar bone resorption was determined by micro-CT (mice without ligation treatment were used as the control group), and the colocalization of GSDMD and CD31 were quantitatively analyzed by immunofluorescence staining in gingival tissues of healthy and inflammatory mice. Human umbilical vein endothelial cells (HUVECs) were cultured in vitro and treated with lipopolysaccharide (LPS) of Porphyromonas gingivalis (Pg) combined with adenosine triphosphate (ATP) at various concentrations of 0.5, 1.0, 2.5, 5.0, and 10.0 mg/L, respectively, and the 0 mg/L group was set as the control group at the same time. Scanning electron microscopy was used to observe the morphology of HUVECs. Western blotting was used to detect the expression of gasdermin D-N terminal domains (GSDMD-N) protein and immunofluorescence cell staining was used to detect the expression and distribution of GSDMD. Cell counting kit-8 (CCK-8) was used to detect the proliferative ability of HUVECs, and propidium iodide (PI) staining was used to detect the integrity of cell membrane of HUVECs. Results:Immunohistochemistry showed that GSDMD in gingival tissues of periodontitis was mainly distributed around blood vessels and its expression level was higher than that in healthy tissues. Micro-CT showed that alveolar bone resorption around the maxillary second molar significantly increased in ligation group mice compared with control subjects ( t=8.88, P<0.001). Immunofluorescence staining showed significant colocalization of GSDMD with CD31 in the gingival vascular endothelial cells in mice of ligation group. The results of scanning electron microscopy showed that there were pores of different sizes, the typical morphology of pyroptosis, on HUVECs cell membranes in the inflammatory environment simulated by ATP combined with different concentrations of LPS, and 2.5 mg/L group showed the most dilated and fused pores on cell membranes, with the cells tended to lyse and die. Western blotting showed that the expression of GSDMD-N, the hallmark protein of cell pyroptosis, was significantly higher in 2.5 and 5.0 mg/L groups than that in the control group ( F=3.86, P<0.01). Immunofluorescence cell staining showed that the average fluorescence intensity of GSDMD in 2.5 mg/L group elevated the most significantly in comparison with that in the control group ( F=35.25, P<0.001). The CCK-8 proliferation assay showed that compared to the control group (1.00±0.02), 0.5 mg/L (0.52±0.07), 1.0 mg/L (0.57±0.10), 2.5 mg/L (0.58±0.04), 5.0 mg/L (0.55±0.04), 10.0 mg/L (0.61±0.03) groups inhibited cell proliferation ( F=39.95, P<0.001). PI staining showed that the proportion of positive stained cells was highest [(56.07±3.22)%] in 2.5 mg/L group ( F=88.24, P<0.001). Conclusions:Endothelial cells undergo significant pyroptosis in both in vivo and in vitro periodontal inflammatory environments, suggesting that endothelial cell pyroptosis may be an important pathogenic factor contributing to the pathogenesis of periodontitis.

Objective: To investigate the changes of mitochondrial homeostasis of human gingival fibroblasts (HGFs) in periodontitis, and to provide a basis for exploring the mechanism of periodontitis. Methods: This study has been reviewed and approved by the Ethics Committee. Gingival tissue was collected from patients who underwent periodontal surgery at the Department of Periodontology, School of Stomatology, the Fourth Military Medical University, from June 1, 2023 to December 31, 2023. All of the subjects signed informed consent forms prior to surgery. Gingival connective tissues were collected from patients with chronic periodontitis (CP group) and healthy individuals (control group) undergoing flap surgery and crown lengthening surgery, respectively. There were 6 cases in each group. The primary HGFs obtained from healthy periodontal subjects were cultured and divided into the control group (cultured in complete medium for 24 h) and the Pg.LPS group (cultured in medium with 5μg/mL Pg.LPS for 24 h). The number, morphology, and structure of mitochondria in gingival connective tissue and HGFs were observed by transmission electron microscopy. The number, circumference, and surface area of mitochondria were quantitatively analyzed. MitoSOXTMRed, TMRM, and an ATP kit were used to determine the production levels of mitochondrial reactive oxygen species, mitochondrial membrane potential, and ATP in each group of HGFs. Results: Transmission electron microscopy showed that the morphology and structure of mitochondria were abnormal in the gingival connective tissues of the periodontitis group and HGFs, which were stimulated by Pg.LPS. The mitochondrial ridges were broken or were not visible in these groups. The number of mitochondria decreased significantly, and the surface area and circumference of the mitochondria increased significantly (P < 0.05). In addition, after stimulation by Pg.LPS, the reactive oxygen species level in HGFs was significantly higher than that in the control group (P < 0.05). The mitochondrial membrane potential and the level of ATP production was significantly lower than that of the control group (P < 0.05). Conclusion The number, morphological structure, and function of mitochondria in HGFs changed significantly in periodontitis. The mitochondrial homeostasis is closely related to the occurrence and development of periodontitis.

Severe muscle injury is hard to heal and always results in a poor prognosis. Recent studies found that extracellular vesicle-based therapy has promising prospects for regeneration medicine, however, whether extracellular vesicles have therapeutic effects on severe muscle injury is still unknown. Herein, we extracted apoptotic extracellular vesicles derived from mesenchymal stem cells (MSCs-ApoEVs) to treat cardiotoxin induced tibialis anterior (TA) injury and found that MSCs-ApoEVs promoted muscles regeneration and increased the proportion of multinucleated cells. Besides that, we also found that apoptosis was synchronized during myoblasts fusion and MSCs-ApoEVs promoted the apoptosis ratio as well as the fusion index of myoblasts. Furthermore, we revealed that MSCs-ApoEVs increased the relative level of creatine during myoblasts fusion, which was released via activated Pannexin 1 channel. Moreover, we also found that activated Pannexin 1 channel was highly expressed on the membrane of myoblasts-derived ApoEVs (Myo-ApoEVs) instead of apoptotic myoblasts, and creatine was the pivotal metabolite involved in myoblasts fusion. Collectively, our findings firstly revealed that MSCs-ApoEVs can promote muscle regeneration and elucidated that the new function of ApoEVs as passing inter-cell messages through releasing metabolites from activated Pannexin 1 channel, which will provide new evidence for extracellular vesicles-based therapy as well as improving the understanding of new functions of extracellular vesicles.
Creatine/metabolism* ; Extracellular Vesicles ; Muscle, Skeletal/metabolism* ; Myoblasts/metabolism* ; Regeneration ; Connexins/metabolism*

Objective : To investigate the effect of different decontamination methods, including photodynamic therapy, sandblasting and titanium curette, on titanium surface morphology and bacterial adhesion for the treatment of peri-implant disease. Methods: Porphyromonas gingivalis (Pg) and Fusobacterium nucleatum (Fn) were inoculated on the surface of polished titanium specimens, and titanium specimen surfaces were treated with different decontamination methods after incubation. The titanium specimens were divided into a no-treatment control group, photodynamic group, sandblasting group and titanium curette group according to different decontamination methods. The changes in titanium surface roughness were observed by atomic force microscopy (AFM), and the remaining bacteria on the titanium surface were observed by scanning electron microscopy (SEM) and live/dead bacteria staining tests. After reinoculation of Pg and Fn, bacterial readhesion was observed on the surface of decontaminated titanium specimens. Results : The AFM results showed that the surface roughness of the titanium curette group was significantly higher than that of the no-treatment control group, photodynamic group and sandblasting group (P<0.05), and there was no statistically significant difference between the no-treatment control group, photodynamic group and sandblasting group (P>0.05). The results of contact angle measurement showed that the surface contact angle of each treatment group was smaller than that of the no-treatment control group (P<0.05). The SEM results obtained after the titanium specimen surface was decontaminated showed that the number of bacteria on the no-treatment control group surface was higher and the bacteria were relatively concentrated. The bacteria on the surface of the photodynamic group, sandblasting group and titanium curette group were scattered and distributed in small numbers, and most bacteria on the surface of the photodynamic group were ruptured. The results of the live/dead bacteria staining experiment showed that the percentage of dead bacteria on the surface of the photodynamic group was significantly higher than that of the no-treatment control group, sandblasting group and titanium curette group (P<0.05). The remaining bacteria on the surface of the sandblasting group and titanium curette groups were mainly live bacteria. The remaining bacterial adhesion on the surface was significantly reduced for the sandblasting group compared to the no-treatment control group and the photodynamic and titanium curette groups (P<0.05). SEM and live/dead bacteria staining results of bacterial readhesion on the surface of titanium specimens showed that there was an aggregation of Pg on the surface of the titanium curette group, and its surface bacterial adhesion was significantly higher than that of the no-treatment control group, photodynamic group and sandblasting group. Conclusion In mechanical decontamination, sandblasting machines are a better option than photodynamic therapy and titanium curettes; however, sandblasting does not remove all bacterial contamination. For sterilization, photodynamic therapy is more effective than sandblasting and titanium curettes. A combination of sandblasting and photodynamic therapy methods for the treatment of peri-implant disease may be considered in clinical practice.

Objective:To study factors influencing postoperative pancreatic fistula rates with a view to prevent postoperation pancreatic fistula from happening.Methods:This is a retrospective study on 281 patients who underwent distal pancreatectomy at the First Affiliated Hospital of China Medical University from March 2011 to April 2018. There were 89 males and 192 females, with the age of (51.01±13.65) years. Univariate and multivariate logistic regression analyses were used to analyze the following factors on the occurrence of pancreatic fistula after operation: gender, age, body mass index(BMI), tumor characteristics, preoperative fasting blood glucose, blood biochemistry, liver function and surgical indications.Results:Of the 281 patients who underwent distal pancreatectomy in this study, 245 (87.2%) did not develop pancreatic fistula / biochemical leakage, while 36(12.8%) patients developed clinically significant pancreatic fistula (B/C grade). Univariate analysis showed the factors which affected the incidence of pancreatic fistula after surgery to include: BMI, preoperative fasting blood glucose, and whether the main pancreatic duct was ligated (all P<0.05). Multivariate logistic regression analysis showed that the independent factors affecting pancreatic fistula incidence after surgery were BMI≥25 kg/m 2 ( OR=2.354, 95% CI: 1.137-4.873, P<0.05), and main pancreatic duct was not ligated ( OR=4.067, 95% CI: 1.191-13.885, P<0.05). Conclusions:A high BMI increased the risk of postoperative pancreatic fistula, while ligation of main pancreatic duct during surgery reduced the risk.

Objective:To investigate the effect and mechanism of periodontal ligament stem cell (PDLSC) from inflammatory environment on the secretion of interleukin-1β (IL-1β) by macrophages.Methods:PDLSCs were pretreated with lipopolysaccharide (LPS) in order to simulate the inflammatory environment. Human monocyte cell line (THP-1) cells were treated with conditioned media collected from healthy and inflammatory PDLSCs respectively and divided into conditioned medium of health PDLSC (CM-H) group and conditioned medium of LPS-PDLSC (CM-LPS) group. After 24 h of co-culture, the condition media were abandoned and THP-1 cells were then cultured for another 24 h. The expression of IL-1β in THP-1 cells supernatant was detected by enzyme-linked immunosorbent assay (ELISA). Quantitative real time-PCR (qRT-PCR) was used to detect the expression of glucose regulated protein 78 (GRP78), activating transcription factor-6 (ATF6), inositol requiring enzyme 1 (IRE1), protein kinase R-like endoplasmic reticulum kinase (PERK), CCAAT enhancer binding protein homologous protein (CHOP), activating transcription factor-4 (ATF4) and X box binding protein 1 spliced (XBP1s), which were all related with endoplasmic reticulum stress (ERS), in THP-1 cells. The expressions of proteins GRP78 and CHOP were detected by Western blotting. Furthermore, THP-1 cells, which pretreated with ER inhibitor 4-phenylbutyrate (4-PBA) for intervention experiments were grouped by various concentrations of 4-PBA including groups 0 (control group), 1, 10 and 20 mmol/L and treated with condition medium of inflammatory PDLSC. ELISA was used to detect IL-1β expression and qRT-PCR to detect expression of ERS related genes.Results:ELISA results showed that the expression of IL-1β in THP-1 cells of group CM-LPS [(31.35±2.11) ng/L] was significantly higher than group CM-H [(8.19±1.51) ng/L] ( t=12.60, P<0.01). qRT-PCR results showed that the relative expressions of GRP78, ATF6, IRE1, PERK, CHOP, ATF4 and XBP1s genes in THP-1 cells of group CM-LPS (1.782±0.070, 1.387±0.204, 1.404±0.119, 1.777±0.187, 1.325±0.156, 1.295±0.066 and 1.137±0.149, respectively) were significantly higher than those in group CM-H ( P<0.05). In the 4-PBA intervention experiment, compared with group 0 mmol/L, the expressions of GRP78, IRE-1, ATF-6, PERK and CHOP were significantly lower in group 1, 10 and 20 mmol/L ( P<0.05). Moreover, compared with control group [(31.23±1.98) ng/L], the expression of IL-1β in THP-1 cells were significantly lower in group 10 mmol/L [(21.20±0.37) ng/L] and group 20 mmol/L [(23.85±1.80) ng/L] ( P<0.05) with ERS inhibited. Conclusions:PDLSC from inflammatory environment could promote IL-1β secretion of macrophages through upregulating macrophages ERS.

Objective:To investigate the effect of low dose lipopolysaccharide (LPS)-treated human periodontal ligament stem cells (HPDLSC) on the expression of macrophage pro-inflammatory factors and the mechanism involved.Methods:The primary HPDLSCs were obtained from healthy third molar periodontal ligament tissue. Phosphate buffer saline (PBS), 100 μg/L or 10 mg/L of LPS were used to treat HPDLSCs for 48 h, and their conditioned media were respectively co-cultured with THP-1-derived macrophages for 48 h. The corresponding experimental groups were PBS-treated HPDLSC-derived conditioned medium (CM-C) group, low dose LPS-treated HPDLSC-derived conditioned medium (CM-L) group, and high dose LPS-treated HPDLSC-derived conditioned medium (CM-H) group. Quantitative real-time PCR was performed to explore the mRNA expressions of macrophage interleukin (IL)-6, IL-8, IL-12, tumor necrosis factor-α (TNF-α) in the CM-C, CM-L and CM-H groups, and the expressions of nuclear factor (erythroid-derived 2)-like 2 (NRF2), glutamate-cysteine ligase catalytic subunit (GCLC), NAD(P)H quinone dehydrogenase 1 (NQO1) and heme oxygenase 1 (HO-1) in the CM-C and CM-L groups. Meanwhile, Western blotting was used to detect the change of nuclear and cytoplasmic NRF2 and the levels of GCLC and HO-1 in the CM-C and CM-L groups. The 2′, 7′-dichlorofluorescein probe was adopted to detect the reactive oxygen species (ROS) levels of macrophages in the CM-C and CM-L groups and the data were characterized by the mean fluorescent intensity (MFI).Results:The mRNA expressions of macrophage pro-inflammatory factors IL-6, IL-8, IL-12 and TNF-α in the CM-H group (2.332±0.594, 3.601±0.639, 2.120±0.677 and 2.468±0.236) were significantly upregulated compared with those in the CM-C group (1.000±0.321, 1.000±0.151, 1.000±0.059 and 1.000±0.095) ( P<0.05); while the relative mRNA levels of IL-6, IL-12 and TNF-α in the CM-L group (0.056±0.002, 0.215±0.024 and 0.567±0.071) were much lower than those in the CM-C group (1.000±0.209, 1.000±0.220 and 1.000±0.220) ( P<0.05). At the mRNA level, the expression of NRF2 was significantly increased in the CM-L group (1.864±0.198) compared with that in the CM-C group (1.000±0.094) ( P<0.05). At the protein level, the cytoplasmic NRF2 and nuclear NRF2 were increased in CM-L group (1.175±0.104 and 1.308±0.082) compared with those in the CM-C group (1.000±0.025 and 1.000±0.049) ( P<0.05). Furthermore, the antioxidative genes, i.e. GCLC and NQO1, localized in NRF2 downstream, were significantly upregulated in the CM-L group (1.786±0.278 and 1.444±0.078) compared with the CM-C group (1.000±0.139 and 1.000±0.226) ( P<0.05). The protein levels of GCLC and HO-1 were augmented in the CM-L group (1.159±0.036 and 1.412±0.075) in contrast with those in the CM-C group (1.000±0.050 and 1.000±0.013) ( P<0.05). In addition, the MFI in the CM-L group (123 419±1 302) was significantly lower than that in the CM-C group (139 193±1 241) ( P<0.05). Conclusions:Low-dose LPS-treated HPDLSCs could regulate oxidative stress response through activating the NRF2 signaling pathway of macrophages and further downregulating the expressions of macrophage pro-inflammatory factors.

Objective:To investigate whether bone marrow mesenchymal stem cells (BMMSCs) derived apoptotic extracellular vesicles (ApoEVs) could regulate the polarization of mouse macrophage cell line RAW264.7 and whether BMMSCs derived ApoEVs could attenuate pro-inflammatory condition of RAW264.7 induced by Porphyromonas gingivalis lipopolysaccharide (Pg-LPS), so as to provide experimental evidence and theoretical basis for using BMMSCs derived ApoEVs as a method to treat periodontitis. Methods:The Operetta CLS high-content analysis system was used to observe the time-dependent apoptosis process of BMMSCs. Besides, field emission scanning electron microscopy (FESEM), dynamic light scattering technology and streaming potential method were used to measure the surface characteristics of BMMSCs derived ApoEVs. The Operetta CLS high-content analysis system was used to observe the process of RAW264.7 phagocyting 5-carboxy-tetramethylrhodamine, succinimidyl ester (5-TAMRA-SE) labeled ApoEVs. Real-time quantitative PCR was used to detect the mRNA expression of arginase-1 (Arg-1). Cell immunofluorescence and Western blotting were used to detect the number of inducible nitric oxide synthase (iNOS)(+) macrophages and iNOS protein expression level in each experiment group. Enzyme linked immunosorbent assay was used to detect tumor necrosis factro-α (TNF-α) level in the Pg-LPS induced pro-inflammatory macrophage culture supernatant in each experiment group.Results:After treating with 0.5 μmol/L staurosporine for 12 hours, mouse BMMSCs underwent shrinking with obvious vesicles structure around. The FESEM showed the ApoEVs were in spherical shapes. The size range of ApoEVs was about 100-1 000 nm and the average Zeta potential was -16.6 mV. The Operetta CLS high-content analysis system showed RAW264.7 could phagocytose 5-TAMRA-SE labeled ApoEVs by pseudopodia. The relative mRNA expression of Arg-1 was significantly increased in RAW 264.7 after being treated with interleukin 4 (IL-4) and ApoEVs (261.97±15.91) compared to that with IL-4 alone (115.29±15.42) ( P<0.01). Cell immunofluorescence showed that ApoEVs could reduce the number of iNOS(+) macrophages induced by Pg-LPS (39.33±4.70) comparing to those without ApoEVs (95.33±4.70) ( P=0.007). In the meanwhile, ApoEVs could also down-regulate the iNOS protein level of macrophages induced by Pg-LPS (5.84±1.05) comparing to those without ApoEVs (14.91±3.87) ( P<0.01). Besides, ApoEVs could also reduce the TNF-α secretion in the culture supernatant of pro-inflammatory macrophages induced by Pg-LPS [(21 899.71±409.73) ng/L] comparing to those without ApoEVs [(71 296.50±2 344.22) ng/L] ( P=0.003). Conclusions:BMMSCs derived ApoEVs could regulate the polarization of macrophages and could also attenuate the pro-inflammatory condition of macrophages induced by Pg-LPS.