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28 February 2022, Volume 38 Issue 2 Previous Issue    Next Issue

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Association of Adaptive Immune Cells and Primary Sjögren's Syndrome CHEN Jiang, LIN Yanjun 2022, 38(2): 99-103.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.001 Abstract ( 189 )   PDF (947KB) ( 389 )   Primary Sjögren's syndrome (pSS) is an autoimmune disease whose pathogenesis changes with adaptive immunity. Learning about the pathophysiological changes of adaptive immune cells in pSS helps us further find immune therapy targets. This paper reviews the current research on the association of pSS and adaptive immune cells at home and abroad. References | Related Articles | Metrics

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Review of Cyclic Loading Effect on Dentin Bonding DING Jingyu, ZHU Song 2022, 38(2): 104-107.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.002 Abstract ( 251 )   PDF (1116KB) ( 345 )   Most researches adopt static loads to assess the dentin bonding. However, the clinical performance of dentin bonding interface is gradually deterious under cyclic loading. Cyclic loading experiments can be generally sorted into aging testing and fatigue testing. This article reviews devices, configurable settings, applications, and additional factors of aging testing and fatigue testing, respectively. References | Related Articles | Metrics

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Research Progress of Porphyromonas Gingivalis Promoting Cardiovascular Disease WU Qinrui, PENG Xian 2022, 38(2): 108-112.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.003 Abstract ( 298 )   PDF (1381KB) ( 530 )   Chronic periodontitis and cardiovascular disease are two common chronic inflammatory diseases in today's society, which are affected by a variety of risk factors. Epidemiological investigations found that chronic periodontitis is closely related to increased cardiovascular disease risk. Porphyromonas gingivalis colonized in the gingival sulcus of chronic periodontitis patients could invade cardiovascular tissues through bacteremia and phagocyte-mediated pathways and secrete virulence factors. By triggering endotoxemia, endothelial dysfunction, oxidative stress, foam cell formation and lipid accumulation, vascular remodeling, plaque rupture and thrombosis, it leads to serious cardiovascular end-events. The study on the specific ways that Porphyromonas gingivalis affects cardiovascular disease provides a new method for the prevention and treatment of cardiovascular disease, thereby reducing the burden of disease in society. References | Related Articles | Metrics

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Research Progress on PDGF/PDGFRβ Pathway Coupling with Osteogenesis and Angiogenesis SU Han, TANG Guohua 2022, 38(2): 113-115.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.004 Abstract ( 298 )   PDF (790KB) ( 543 )   Osteogenesis and angiogenesis are indispensable to development and regeneration of bone, and their coupling is a crucial factor in bone formation. Platelet-derived growth factor receptor beta (PDGFRβ) belongs to the class Ⅲ receptor tyrosine kinase, which participates in a variety of physiological activities in cells and tissues through the downstream signal cascade, after the combination with corresponding platelet-derived growth factors (PDGFs). With broader studies on tissue engineering and regenerative medicine, the participation of such pathway in the regulation of activities of microvascular system and osteoblast lineage has been founded by various scholars, indicating that PDGF/PDGFRβ pathway plays an important role in the coupling of osteogenesis and angiogenesis. References | Related Articles | Metrics

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Anatomy and Application Progress of Supraclavicular Artery Flap in Reconstruction of Oral and Maxillofacial Defects WENG Yanming, GUO Jiaping 2022, 38(2): 116-119.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.005 Abstract ( 206 )   PDF (1424KB) ( 382 )   Primary reconstruction following oncologic resection in oral and maxillofacial field is a challenge in clinical treatment. Although free flaps are the mainstream for repairing oral and maxillofacial defects, pedicled tissue flaps still play an important role in the reconstructive surgery. The supraclavicular artery flap (SAF) is gaining an increased popularity over recent years because of its stable blood perfusion, similar color and texture to nearby skin, moderate thickness, and satisfactory repair effect. The SAF is easy to harvest, and does not require vascular anastomosis. The application of SAF may help to save medical resource and lighten the burden of patients. This article reviews the anatomy, design, advantages, disadvantages, and clinical application of the SAF. References | Related Articles | Metrics

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Analysis of Digital Pioneer Drilling Guide and Full Process Guide in Full Arch Implant Placement JIAO Tiejun, LI Bolong, FU Na 2022, 38(2): 120-124.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.006 Abstract ( 327 )   PDF (4011KB) ( 351 )   Objective: To evaluate the clinical outcome of full arch implant placement using digital pioneer drilling guide and full guide. Methods: The present study was conducted on 15 patients who received full arch implant placement in the Department of Implantology School and Hospital of Stomatology, Tianjin Medical University between October 2016 to October 2020. There were 6 males and 9 females aged (57.5±6.3) years. There were 6 cases of complete dentition loss and 9 cases of single arch dentition loss. For specific surgical site, 11 were maxilla edentulous and 10 were mandible. 11 cases were conducted with the help of digital pioneer drilling guide and the other 10 cases were accomplished using digital full guide. A total of 121 implants were placed. Three dimensional positions of implants were compared pre- and post-surgery to assess the accuracy of these digital guides. The accuracy of the two digital guides and the duration of implant operation were evaluated. Results: 121 implants were placed under digital guide. One implant disloaded three months after provisional prosthesis and the patient was subsequently loaded on the rest 5 implants. All other cases were finished according to the original plan and no failure happened during the review period. For maxillary and mandible fully guided implant placement, the implant insertion axial direction angulation, and cervical and apical deviation were significantly smaller than digital pioneer drilling guided surgery (P<0.05). The operation time of patients with full digital guide was significantly shorter than that of patients with pioneer drill guide, no matter in maxilla or mandible. Conclusion: Full guided system is more accurate and reduced the operation time in contrast to pioneer drilling guided for full arch implant placement. References | Related Articles | Metrics

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Clinical Retrospective Study on Combination of Screw and Adhesive Retention in Multi-unit Implant Restoration ZHOU Liwei, LI Mengquan 2022, 38(2): 125-128.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.007 Abstract ( 212 )   PDF (1333KB) ( 533 )   Objective: To compare the differences among SCP (screw and cement-retained implant-supported dental prosthesis) group, adhesion retention group, and screw retention group for multi-unit implant crown restoration. Methods: A total of 152 patients (331 implants) were collected, in which 44 cases (94 implants) were fixed with screws, 56 cases (121 implants) were treated with intraoral adhesion, and 52 cases (116 implants, 52 implants were retained with screws and 64 implants with adhesive retentions) were treated with SCP. The incidences of adhesion and screw mechanical complications in 3 groups were compared after 2-year use. Results: There was no significant difference in the incidence of screw loosening between the SCP group and the cement-retained group, but these incidences of both groups were lower than that in the screw-retented group. There was no significant difference in the failure rate between the intraoral bonding units of SCP group and the extraoral bonding units of screw-retented group (P>0.05). Conclusion: The multi-unit SCP retention method can reduce the risk of screw loosening and bonding failure while having passive fit, and is suitable for the cases with insufficient occlusal space for crown restoration and/or with deep soft tissue cuff. References | Related Articles | Metrics

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Efficacy Comparison of CGF Gel and CGF Extracting Solution in Alveolar Ridge Preservation through Voxel-based Superimposition of Cone Beam Computed Tomography Images DAI Jiaxiu, LIU Xiaohui, LIU Yu, XU Shuyu 2022, 38(2): 129-133.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.008 Abstract ( 173 )   PDF (2673KB) ( 260 )   Objective: To compare the efficacy of concentrated growth factor (CGF) gel and CGF extract combined with low replacement rate osteogenic materials for site preservation surgery. Methods: Eighteen patients were randomly divided into two groups. CGF gel group: CGF gel and DBBM were mixed at 1∶1 to fill the bone defect, and CGF extract solution group: the bone defect was filled with the mixture of CGF extract solution and DBBM. Voxel-based superimposition of cone beam computed tomography images were taken before operation, on the same day after operation, and 6 months after operation. Results: From postoperative day to six months after operation, there were significant differences in the mesiodistal height and buccal-lingual height between CGF gel group and CGF extract solution group, and the bone height resorption in CGF gel group was higher than that in CGF extract solution group, but there was no significant difference in mesiodistal width and buccal-lingual width between two groups. Conclusion: The osteogenic effect of CGF extract solution group is better than that of CGF gel group at 6 months after operation. References | Related Articles | Metrics

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Influence of Different Bone Types on Accuracy of Digital Dental Implant Guide JIANG Xiangrui, XUE Kun, LI Baozuo 2022, 38(2): 134-137.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.009 Abstract ( 218 )   PDF (2265KB) ( 327 )   Objective: To analyze the influence of different bone types on the accuracy of digital implant guide. Methods: According to the set inclusion and exclusion criteria, a total of 62 patients were included, the implant surgery assisted by digital guide plate was performed for all patients. The implant position after different bone implant surgery was matched with the preoperative design position. Results: The patients were aged from 34 to 74 years old, with an average of (49.6±9.69) years old. The shoulder offset of 62 implants was (1.38±0.26) mm, the apical offset was (1.57±0.24) mm, the angle offset was (1.75±0.62)°, and the apical offset was slightly larger than shoulder offset. The shoulder deviation of grade I bone was greater than that of grade Ⅱ, Ⅲ, and Ⅳ bone (P<0.05). The apical deviation of grade Ⅰ and Ⅳ bone was greater than that of grade Ⅱ and Ⅲ bone (P<0.05). The angle deviation of grade Ⅰ bone was greater than that of grade Ⅱ, Ⅲ, and Ⅳ bone (P<0.05). Conclusion: The accuracy of dental digital implant guide is affected by different bone types. Grade Ⅱ and Ⅲ bone are the best bone for digital implant guide. References | Related Articles | Metrics

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Stress Analysis of Different Types of Implants Implanted in Two Types of Bone at Different Angles ZHOU Hongzhi, ZHANG Ke, WANG Xueling, WANG Wenjie, WANG Wentian 2022, 38(2): 138-143.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.010 Abstract ( 211 )   PDF (3552KB) ( 321 )   Objective: To compare the effects of implant shape and implant angle on the stress of implant components and surrounding bone under different bone conditions by three-dimensional finite element analysis (FEA). Methods: The geometric models of cylindrical and tapered implants were established by using relevant software. The implants were implanted into class Ⅱ and class Ⅲ jaw models at the angles of 0°, 10°, 20°, and 30° respectively, and the two-stage individualized abutment with corresponding angles was used for restoration. The models were loaded by simulating three stress states. The peak stress and stress distribution were observed. Results: The stress of each component of the denture and the surrounding bone increased with the increasing of implant angle. Under the same load condition, the peak stress around the implant in class Ⅱ bone was significantly smaller than that in class Ⅲ bone. The peak stress in the columnar implant group was smaller than that in the tapered implant group, while that in the surrounding bone and the upper Ti-base stress was relatively larger. Conclusion: The direction of the implant had better be aligned with the axis of natural tooth to reduce the adverse effects of lateral force. Class Ⅱ bone was more conducive to disperse the stress than class Ⅲ bone. The tapered implant was beneficial to disperse the stress and help to protect the surrounding bone tissue, however, it was more prone to mechanical complications than the cylindrical implant. References | Related Articles | Metrics

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Study on Platelet-Rich Fibrin Promoting Gingival Tissue Repair and Regeneration WANG Yuhui, LV Huixin, ZHANG Mingrui, WANG Yingying, REN Sicong, ZHENG Shikang, LIN Xinping, ZHOU Yanmin 2022, 38(2): 144-149.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.011 Abstract ( 241 )   PDF (5488KB) ( 338 )   Objective: To observe the effect of platelet-rich fibrin on the biological behavior of primary cells and tissue regeneration in the repair of gingival defects. Methods: PRF membrane was prepared. Scanning electron microscope and histopathology were used to observe the ultrastructure. CCK-8 and transwell test was used to detect cell proliferation and migration ability. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of soft tissue healing marker genes COL-I and TGF-β at different time points. HE staining and immunohistochemistry were used to observe tissue healing at different time points, and qRT-PCR was used to detect the expression of inflammatory factors IL-6, TNF-α, and TGF-β. Results: PRF could promote the proliferation, healing, and migration of human gingival fibroblast after trauma (P<0.05). The expressions of COL-I and TGF-β in the PRF group were higher than those in the DMEM group on day 7 (P< 0.05). The healing effect of PRF group was better than that of the control group. Histological observations showed that the PRF group had less inflammatory cell infiltration than the control group, and the PRF group had more angiogenesis than the control group. On day 7 after operation, the expression of IL-6 and TNF-α in the control group was higher than that in the PRF group, and the expression of TGF-β in the control group was lower than that of the PRF group (P<0.05). VEGF immunohistochemical results showed that the expression of positive cells in the PRF group was earlier than that in the control group. Conclusion: PRF can promote the expression of COL-I, TGF-β, and VEGF in the gums, reduce the local inflammation, and accelerate tissue healing. References | Related Articles | Metrics

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Effect of Attachment Type on the Stress of Short Implant-assisted Removable Partial Dentures at Different Implant Positions AN Weikang, LIU Lipeng, ZHANG Wei, ZHENG Yafei, LIU Jingjing, WANG Qing, MA Chufan 2022, 38(2): 150-156.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.012 Abstract ( 200 )   PDF (5498KB) ( 270 )   Objective: To compare influences of attachment type and different implant sites on the stress distribution among all supporting structures. Methods: A three-dimensional finite element model of a short-implants-assisted removable partial denture was established to restore Kennedy class Ⅰ dentition defect, and nine experimental group models were constructed according to the implant positions (position A: the second premolar area, position B: the first molar area, position C: the second molar area) and attachment types (Brevis, Locator, and Magfit). A removable partial denture model was established as the control. The stress distribution of each component was analyzed, and the maximum von Mises stress values and displacement values were recorded. Results: Three-dimensional finite element models of short implant-assisted removable partial denture were established. Under vertical and oblique loads, the denture displacement was greater in the RPD group than in the experimental groups; under oblique loads, the denture displacement was greater in the Magfit groups than in the Brevis and Locator groups, while the implant-bone interface stress was smaller and the mucosa stress and cortical bone stress around the short implant were greater; the implant-bone interface stress and short implant stress were smaller, and the short implant stress was greater when the short implant was located at position C. Conclusion: Short implants-assisted removable partial dentures can significantly improve the retention and stability of the denture, and magnetic attachments are more beneficial to the long-term success of short implants. Position C is better suited for dispersion of occlusal forces. References | Related Articles | Metrics

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Effect of Polygonatum Sibiricum Polysaccharides on Osteogenic Differentiation of Adipose Derived Stem Cells in Osteoporosis Mice LU Shi, HE Qingming, LOU Fangzhi, PENG Shuanglin, GAO Yujin, XIAO Jingang 2022, 38(2): 157-163.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.013 Abstract ( 220 )   PDF (8585KB) ( 319 )   Objective: To study the effect of polygonatum sibiricum polysaccharides (PSP) on osteogenic differentiation of adipose derived stem cells in osteoporosis mice (OP-ASCs). Methods: Osteoporosis mouse model was established. OP-ASCs were isolated and cultured in vitro. Cell proliferation was detected by CCK-8 method after using different concentrations of PSP to intervene in OP-ASCs. Osteogenic capacity was analyzed by western-blot, real-time PCR, and ALP staining at day 3 and 5 after osteogenic differentiation in PSP-intervened OP-ASCs. Results: When the concentration of PSP was 5, 10, 25, and 50 mg/L, the proliferation of OP-ASCs was not significantly affected on day 3 and 5 (P>0.05). Western-blot and real-time PCR results showed that Runx2, OPN, β-catenin, P-GSK-3β protein and Runx2, Opn, β-catenin gene expression in the treatment group were significantly higher than those in the control group (P<0.05). ALP staining showed that the osteogenic effect was significantly higher than the control group. Conclusion: PSP can enhance osteogenic differentiation of OP-ASCs, which may be achieved by up-regulating Wnt/β-catenin signaling pathway. References | Related Articles | Metrics

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Effects of Soluble Epoxide Hydrolase Inhibitor on Proliferation and Osteogenic Differentiation of Stem Cells from Apical Papilla in Inflammatory Environment DANG Haixia, WANG Fu, CHEN Lan, WANG Yulin, ZHOU Zhiqiang 2022, 38(2): 164-168.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.014 Abstract ( 178 )   PDF (2058KB) ( 214 )   Objective: To investigate the effect of TPPU on proliferation and differentiation of hSCAPs in the inflammatory microenvironment. Methods: hSCAPs were cultured and identified by flow cytometry and alizarin red staining. The hSCAPs were treated with 1 mg/mL lipopolysaccharide (LPS) to simulate the inflammatory microenvironment, and then treated with TPPU. The CCK-8 method was used to study whether TPPU had an effect on the proliferation ability of hSCAPs on the first 1, 3, 5, and 7 days. After 24 hours cultivation, the expressions of inflammation-related factors were detected by qRT-PCR. On the day 7 and 12, the expression levels of genes related to osteogenic differentiation were detected by qRT-PCR. On the day 7, ALP activity was analyzed by staining. On day 21, the formation of mineralized nodules was observed by alizarin red staining. Results: hSCAPs were confirmed by flow cytometry and alizarin red staining. CCK-8 results showed that there was no significant difference in OD value between hSCAPs. The expression of IL-1β and IL-6 of hSCAPs induced by LPS was significantly up-regulated compared with the vehicle group (P<0.05). Compared with the LPS group, the expression of IL-1β and IL6 in LPS+TPPU group was significantly down-regulated (P<0.05), but the expression levels of osteogenic genes in LPS+TPPU group were significantly up-regulated (P<0.05). ALP staining and alizarin red staining showed that the TPPU treated groups had deeper staining than LPS groups. Conclusion: TPPU can inhibit the expression of inflammatory factors in inflammatory microenvironment. TPPU may not promote the proliferation, but promote the tooth/osteogenic differentiation of hSCAP in inflammatory microenvironment. References | Related Articles | Metrics

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SIRT1 Enhances Osteogenesis in Stem Cells from Human Exfoliated Deciduous Teeth via Downregulation of Peroxisome Proliferator-Activated Receptor CAO Wei, LIU Mengjia, ZHANG Qingbin 2022, 38(2): 169-175.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.015 Abstract ( 168 )   PDF (3650KB) ( 275 )   Objective: To identify the role of SIRT1 on osteogenic differentiation of stem cells from human exfoliated deciduous teeth. Methods: A defined concentration of SIRT1 activator (SRT1720) and inhibitor (EX527) is 0.5 μmol/L. Then SRT1720 and EX527 were added to the experiment groups for preconditioning 3 days. We investigated the effects of SIRT1 on the osteogenic differentiation of SHEDs. Expression of osteoblastic differentiation markers was assessed by RT-PCR. Results: Activation of SIRT1 using SRT1720 increased the expression of osteoblastic differentiation markers, as assessed by alkaline phosphatase, Runt-related transcription factor-2, osteopontin, collagen type Iα1, and osteocalcin. In contrast, inhibition of SIRT1 using EX527 suppressed the expression of above-mentioned factors. Conclusion: SIRT1 is a key regulator of differentiation of stem cells from human exfoliated deciduous teeth. SIRT1 also regulated the expression of PPAR-γ. The SIRT1/PPAR-γ pathway may be crucial for enhancement of osteogenesis. References | Related Articles | Metrics

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Analysis of Clinical and CT Imaging Features of Metastatic Adenocarcinoma of the Jaw SHAN Shan, YANG Zhenyu, WANG Tiemei, LIN Zitong, FENG Yinglian, Pakezhatia·SEYITI, HUANG Xiaofeng, ZHANG Lei, SUN Guowen 2022, 38(2): 176-180.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.016 Abstract ( 198 )   PDF (4330KB) ( 359 )   Objective: To explore the features of metastatic adenocarcinoma of the jaw (MAJ) with oral and maxillofacial lesions as the first symptom. Methods: Fourteen cases of MAJ from 2006 to 2020 were collected. The clinical and CT features were analyzed retrospectively. Results: The primary sites were lung (n=6), liver (n=4), kidney (n=2), prostate (n=1), and cardia (n=1). CT manifestations were classified as 5/14 osteolytic type with permeative destruction margin, 4/14 mixed type mostly with moth-eaten destruction margin, 3/14 cystic type and 1/14 alveolar bone resorption type with geographic destruction margin, and 1/14 osteoblastic type with sclerotic destruction margin. Conclusion: MAJ usually occurs in the middle-aged and elderly men, especially in the posterior part of mandible. It is the first time to add the cystic type and alveolar bone resorption type on the basis of classical classification. MAJ is characterized by rapidly progressive osteolytic bone destruction with periosteal reaction and localized soft tissue mass without jaw expansion, which plays an important role in differential diagnosis. References | Related Articles | Metrics

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CBCT Retrospective Study on Proportion of Displaced Root Fractures after Root Canal Therapy from 2014 to 2019 HAO Yanqing, TANG Rong, WANG Jinmeng, LIN Zitong 2022, 38(2): 181-185.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.017 Abstract ( 157 )   PDF (1243KB) ( 508 )   Objective: To conduct a retrospective study on the proportion of endodontically treated displaced root fracture teeth in all root fracture teeth based on oral and maxillofacial cone beam computed tomography (CBCT) from 2014 to 2019. Methods: The CBCT images in our hospital from 2014 to 2019 were screened. 1230 patients with 1262 root fractured teeth were enrolled in this study. The age, gender, medical history of root canal therapy, and tooth position was recorded. They were divided into two types: endodontically treated displaced root fracture (ETDRF) and non-endodontically treated displaced root fracture (NETDRF). The proportion of ETDRF and NETDRF in the total number of root fracture teeth was statistically analyzed, and the age, gender, tooth position, and type of root fractures of two groups were statistically analyzed. Results: Compared with 2014-2016, the proportion of ETDRF in total root fracture from 2017 to 2019 significant increased, and there were significant differences between 2014 and 2017, 2018 and 2019 (P<0.05). The average age of ETDRF patients was (56.2±13.4) years old, and NETDRF patients was (56.8±11.4) years old. There were no significant differences between two groups in different years (P=0.372 and P=0.273). The proportion of ETDRF teeth in female root fracture teeth significantly increased in 2017-2019 than that in 2014-2016, and there was a significant difference between 2014 and 2017 (P<0.001). Compared with 2014-2016, the proportion of ETDRF premolars in total root fracture of premolars significantly increased in 2017-2019. The maxillary premolars were significantly different in 2014, 2015, 2016 and 2018 (P<0.05), and the mandibular premolars were significantly different in 2014, 2015, 2016 and 2017 (P<0.05). Vertical ETDRF significantly increased in 2017-2019 than in 2014-2016, while vertical NETDRF did not change obviously from 2014 to 2019. There were significant difference between 2014, 2015 with 2017, 2018, 2019, 2016 with 2017, 2019 (P<0.05). Conclusion: The proportion of ETDRF teeth in total root fractured teeth increased in 2017-2019 than in 2014-2016. ETDRF in female and maxillary and mandibular premolars increased significantly, and vertical ETDRF increased. References | Related Articles | Metrics

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Analysis of Condylar Movement Trajectories in Patients with Temporomandibular Joint Disc Displacement ZHOU Yanli, ZHOU Weina, YU Linfeng, WANG Chen, WANG Bingjie, ZHANG Jinglu 2022, 38(2): 186-190.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.018 Abstract ( 241 )   PDF (2278KB) ( 306 )   Objective: To explore the effect of disc displacement on condylar movements in patients with temporomandibular joint disc displacement. Methods: Eighteen patients with bilateral disc displacement without reduction (DDwoR), 18 patients with bilateral disc displacement with reduction (DDwR), and 10 healthy controls (HC) were included. The trajectories of the condylar hinge axis when doing opening-closing and protrusive-retrusive movements were recorded by computer aided diagnosis axiograph, respectively. The maximum displacement of condyle (Smax), the sagittal condylar track inclination when condylar displacement was 5mm (SCI5), the sagittal condylar track inclination when condylar displacement was maximum (SCI), and reproducibility of condylar movement on the sagittal plane (R) were calculated. Variance analysis was used to compare the differences among the three groups. Results: During opening-closing movement, Smax and SCI5 in DDwoR group were significantly lower than those in DDwR group and HC group. SCI of DDwR group was lower than that of DDwoR group and HC group while R of DDwR group was significantly greater than that of DDwoR group and HC group. When doing protrusive-retrusive movement, the SCI5 and SCI in DDwoR group were significantly lower than those in DDwR group and HC group. The R of DDwR and DDwoR group was significantly higher than that of HC group. Conclusion: The condylar movement trajectories of patients with different types of disc displacement have different characteristics, providing reference for clinical diagnosis and treatment of temporomandibular joint disc displacement. References | Related Articles | Metrics

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Gender Differences of Anxiety Induced by Occlusal Interference in Mice LI Juan, XU Ming, ZHANG Qi, LIU Weicai 2022, 38(2): 191-196.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.019 Abstract ( 174 )   PDF (4541KB) ( 293 )   Objective: To observe and compare the anxiety-like behavior of male and female mice, the neural activation in brain regions related to emotional regulation, and corticosterone levels in serum. Methods: 8-week-old C57BL/6 mice were randomly divided into male occlusal interference group, male control group, female occlusal interference group, and female control group. On day 7 and day 14, the anxiety of mice was detected by open field test, elevated plus maze, and light-dark box test, the activation of neurons in emotion-related brain areas was observed by immunohistochemical staining, and the serum corticosterone levels was detected to evaluate the body's stress level. Results: Behavioral test results showed that the anxiety-like behavior of mice in both male and female occlusal interference group increased significantly (P<0.05), but there was no significant statistical difference between these two groups. Immunohistochemical staining results showed that the activation level of medial prefrontal cortex, insular cortex, nucleus accumbens, central amygdala, basolateral amygdala, and parasubthalamic nucleus of male and female mice were increased significantly after occlusal interference (P<0.05). Serum corticosterone results showed that serum corticosterone levels of female occlusal interference group increased significantly (P<0.05), while there was no significant statistical difference in male occlusal interference group on the 14th day after modeling (P>0.05). Conclusion: The experimental occlusal interference of anterior teeth can lead to an increase of anxiety-like behaviors and a significant increase of neuronal activation in emotion-related brain regions in male and female mice in a short period of time, and lead to increased stress levels in female mice. References | Related Articles | Metrics

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Early Removal of Internal Fixation to Solve Moderate Condylar Displacement after Orthognathic Surgery: A Case Report SHI Shuhan, MA Guowu 2022, 38(2): 197-198.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.020 Abstract ( 269 )   PDF (2460KB) ( 297 )   Postoperative displacement of condyle could be observed in orthognathic surgery. Here we reported a case that the Surgery-First Approach patient who had postoperative moderate displacement of condyle was successfully corrected by the early removal of internal fixation and traction with intermaxillary elastics. References | Related Articles | Metrics

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Minimally Invasive Procedure of Deeply Impacted Right Mandibular Second Molar with Hyperplastic Dental Follicle: A Case Report LI Tingting, SUN Rui, ZHAO Jihong 2022, 38(2): 199-202.  DOI: 10.13701/j.cnki.kqyxyj.2022.02.021 Abstract ( 197 )   PDF (6607KB) ( 457 )   Impacted mandibular second molars are rare, and occur on only one side of the mandible generally. Hyperplastic dental follicles are entities with few cases described to date, and most of them are accompanied with impacted teeth. This case report presented a deeply impacted mandibular second molar with hyperplastic dental follicle, and the roots of the tooth adjoined the lower margin of the mandible. A minimally invasive surgical procedure was performed to extract the tooth and curettage the dental follicle, which came to a favorable prognosis. References | Related Articles | Metrics