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Table of Content

    01 November 2020, Volume 47 Issue 6 Previous Issue    Next Issue
    Expert Forum
    Development and clinical application of proximal matrix system
    Xue Jing
    Int J Stomatol. 2020, 47 (6):  621-626.  DOI: 10.7518/gjkq.2020105
    Abstract ( 2964 )   HTML ( 604 )   PDF(pc) (5893KB) ( 2898 )   Save

    The proximal matrix system is a set of tools used in replacing the side wall of missing teeth and forming the physiological shape of interproximal teeth for the purpose of achieving good contact relationship. These tools mainly include a shaping sheet, retainer, split ring, and interproximal wedge. The creation and development of the proximal matrix system increased the successful rate of adjacent surface filling and restoration and facilitated the progress of composite resin repair materials. It is gradually derived into two categories: the sectional matrix and circumferential matrix systems. Starting from the historical development of the proximal matrix system, this paper describes the design and application of several kinds of proximal matrix systems that are mainly used in clinics, their indications, and main advantages and disadvantages and makes a prospect for the future.

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    Original Articles
    Expression of autophagy related genes in mice periodontal tissue during orthodontic tooth movement
    Yin Yuanyuan,Ma Huayu,Li Xinyi,Xu Jingchen,Liu Ting,Chen Song,He Shushu
    Int J Stomatol. 2020, 47 (6):  627-634.  DOI: 10.7518/gjkq.2020091
    Abstract ( 958 )   HTML ( 21 )   PDF(pc) (14503KB) ( 238 )   Save

    Objective To investigate the level of autophagy related genes in periodontal tissue during orthodontic tooth movement in an experimental C57B/6 mice model and explore the role of autophagy related genes in bone modeling during orthodontic tooth movement. Methods Thirty-11-week-old male C57B/6 mice were randomly divided into 3 groups. Each group contained 10 mice. The experimental model of orthodontic tooth movement was established in group A by applying active force-loading nickel-titanium springs. Springs were placed in group B without force loading. Group C served as blank group. All the springs were placed between the left maxillary first molar and incisor. The mice were sacrificed on day 12, and the left lateral maxillae were collected to prepare sample sections of the periodontal tissue of the left maxillary first molars. Tooth movement was measured via microcomputed tomography. Hematoxylin and eosin (HE) staining, tartrate-resistant acid phosphatase (TRAP) staining, and real-time quantitative polymerase chain reaction (RT-qPCR) were performed, and the expression levels of bone modeling-related genes [osteoprotegerin (OPG) and receptor activator of nuclear factor-κ B ligand (RANKL)] and autophagy related genes (including Atg5, Atg7 and Beclin-1) were detected. Results The mean distance of first molar tooth movement was 0.09 mm in group A. HE staining showed that the amount of periodontal space between the pressure side and tension side of the first molars differed in group A. TRAP staining showed the presence of TRAP-positive cells in the pressure side of the first molar, and the number of osteoclasts in the pressure side was higher than that in the tension side (P<0.05). RT-qPCR results indicated that compared with those in group B, the messenger RNA (mRNA) expression of OPG in the periodontal tissue of group A decreased, whereas the mRNA expression levels of RANKL, Atg5, Atg7 and Beclin-1 increased (P<0.05). Conclusion Autophagy related genes increased in periodontal tissues under orthodontic force. Autophagy may play an important role in bone modeling during orthodontic tooth movement by regulating osteoclastogenesis.

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    Physiological and biochemical study of acupoint mid-frequency pulse electrical stimulation on masseter muscle adapta-tions in rats with mandibular
    Chen Qingqing,Liu Zhenqiao,Wang Yurong
    Int J Stomatol. 2020, 47 (6):  635-643.  DOI: 10.7518/gjkq.2020102
    Abstract ( 933 )   HTML ( 10 )   PDF(pc) (22034KB) ( 64 )   Save

    Objective This study aimed to investigate the effects of acupoint mid-frequency pulse electrical stimulation on the surface electromyography and the expression of brain-derived neurotropic factor (BDNF) in the mandibular protrusion of Sprague-Dawley (SD) rats. Methods Sixty male SD rats were randomly divided into three large groups, namely, blank control, conditional control (with functional appliance and without acupoint mid-frequency pulse electrical stimulation therapy) and experimental groups (with functional appliance and acupoint mid-frequ- ency pulse electrical stimulation therapy). Each large group was randomly divided into four groups (3, 7, 14 and 21 days according to the number of experimental observation days), resulting in 12 groups (n=5). In this experiment, acupuncture points were selected on both sides of the rat, and the parame-ters of acupoint mid-frequency pulse electrical stimulation therapy were set as follows: sinusoidal waveform, 0-150 Hz modulation frequency, and 2 000-8 000 Hz intermediate frequency electrical frequency. The BL-420F biological signal acquisition and analysis system was used to record the electromyograms of rats in the resting state at different experimental periods (3, 7, 14, and 21 days). Immunohistochemistry and real-time quantitative polymerase chain reaction were carried out to detect the protein and mRNA expression levels of BDNF in the masseter muscle of rats. Results The electromyo-grams of masseter muscle, the protein and mRNA expression levels of BDNF first increased and then decreased in the experimental and condition control groups. Moreover, the electromyography of masseter muscle, the protein and mRNA expression levels of BDNF in the experimental group were higher than those in the condition control group on day 3 (P<0.05); the electromyography of masseter and the protein and mRNA expression levels of BDNF in the experimental group basically returned to the normal level on day 21, while those in the condition control group remained higher than those in the blank control group (P<0.05). Conclusion Acupoint mid-frequency pulse electrical stimulation therapy can improve the expression of BDNF in the masseter muscle of rats with functional mandibular protrusion in the early stage, accelerate the recovery of the masseter muscle to normal level, and may improve the treatment of functional appliance.

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    Comparison of clinical outcomes between using bone graft alone and the combination of bone graft with membrane for periodontal regeneration therapy: a systematic review and Meta-analysis
    Wang Shiqi,Chang Yaqin,Chen Bin,Tan Baochun,Ni Yanhong
    Int J Stomatol. 2020, 47 (6):  644-651.  DOI: 10.7518/gjkq.2020110
    Abstract ( 845 )   HTML ( 18 )   PDF(pc) (6948KB) ( 262 )   Save

    Objective This study aimed to compare the clinical effect of using bone graft alone with the combination of bone grafts and membrane in the periodontal regeneration therapy. Methods Relevant studies on the comparison of using bone graft alone and the combination of bone graft with membrane published from June 1988 to May 2019 were identified by electronic and manual search in PubMed, Cochrane, Embase, Web of Science, CNKI, CBM and Wanfang Databases. Using RevMan 5.3 software to make a statistical analysis of all the clinical outcomes. Results Twenty-two studies ful-filling the inclusion criteria were included in the analysis. After assessment, fifteen studies were selected for Meta-analysis and systematic review. Results showed at 6 months of post-surgery, there has no significant differences between bone grafts group and the combined group in terms of clinical attachment level, probing depth and vertical bone fill (P>0.05). For the gingival recession, the combined use of non-absorbable membrane lead to more recession (P<0.05) while the use of absorbable membrane lead to less recession (P<0.05). Conclusion Both the combined therapy and bone grafts alone are effective in the periodontal regeneration therapy, but the statistically differences between two methods were not observed in this limited study except for the gingival recession.

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    Reviews
    Advances in mechanisms for osteogenic differentiation of human periodontal ligament cells induced by cyclic tensile stress
    Li Jingya,Shui Yusen,Guo Yongwen
    Int J Stomatol. 2020, 47 (6):  652-660.  DOI: 10.7518/gjkq.2020111
    Abstract ( 815 )   HTML ( 27 )   PDF(pc) (9076KB) ( 329 )   Save

    Orthodontic tooth movement (OTM) is a complex mechanical-biological mechanism, which is biologically based on mechanical-mediated periodontal tissue remodelling. Bone resorption on the pressure side and bone deposition on the tension side of the periodontal ligament could be observed. Human periodontal ligament cells (hPDLCs) were found to support osteogenic differentiation and periodontal tissue regeneration and maintain homeostasis. At present, many studies have used cyclic tension stress (CTS) for mechanical stimulation during orthodontic treatment to understand the osteogenic differentiation of tension-side hPDLCs. In this review, we will probe into how hPDLCs, as mechanosensitive cells, create initial induction to mechanical signals and then convert primary signals into downstream signals via different mechanotransduction signal pathways. After mechanosensitive cells are regulated, gene expression and protein synthesis are performed. Finally, the paradentium implements bone remodelling. Therefore, this review focuses on the molecular signals and pathways involved in this mechanical signal transduction to discuss how hPDLCs biologically respond to CTS stimulation. This review can provide theoretical evidence for shortening orthodontic treatment time and possible insights into the mechanisms of OTM for further studies.

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    T helper cell 17 and periodontitis related osteoimmunology
    Lü Hui,Wang Hua,Sun Wen
    Int J Stomatol. 2020, 47 (6):  661-668.  DOI: 10.7518/gjkq.2020070
    Abstract ( 1036 )   HTML ( 27 )   PDF(pc) (8752KB) ( 200 )   Save

    T helper cell 17 (Th17), a T cell subset capable of secreting interleukin-17, plays an important role in innate and adaptive immunity and participates in the osteoimmunology of periodontitis by secreting various characteristic cytokines and proteins. Periodontitis is one of the most common inflammatory oral diseases. Periodontitis-related bone loss results from a direct damage caused by pathogenic microorganisms and local stimulating factors and from an indirect damage caused by immune response of host to persistent plaque microorganisms, in which Th17 cell plays an important role. This review aimed to determine the differentiation process of Th17 cell and its influencing factors and explore the role of Th17 cells in bone immunity, especially its influence on mesenchymal stem cells, osteoblasts and osteoclasts.

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    Application of photodynamic therapy for oral carcinogenesis prevention
    He Yuqing,Dan Hongxia,Chen Qianming
    Int J Stomatol. 2020, 47 (6):  669-676.  DOI: 10.7518/gjkq.2020088
    Abstract ( 1456 )   HTML ( 41 )   PDF(pc) (7844KB) ( 361 )   Save

    Oral carcinogenesis starts from the oral mucosa to oral potentially malignant disorder (OPMD) and eventually leads to oral cancer. Substantial effort has been directed to prevent oral carcinogenesis at its early stage; however, success is elusive. Photodynamic therapy is based on photosensitiser-mediated photochemical and photobiological effects leading to cellular damage in lesional tissues. This technique is a new treatment option for OPMD and oral squamous cell carcinoma. This article reviewed the application of photodynamic therapy for oral carcinogenesis prevention.

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    Research progress on 3D printing technology and biomaterials for bone reconstruction in maxillofacial regions
    Zhang Xinchi,Wu Wei
    Int J Stomatol. 2020, 47 (6):  677-685.  DOI: 10.7518/gjkq.2020073
    Abstract ( 1207 )   HTML ( 51 )   PDF(pc) (8620KB) ( 326 )   Save

    Maxillofacial bone defect reconstruction remains a critical challenge in clinical surgery. With the advantages of rapid prototyping, accurate design and personalisation, 3D printing technology plays an important role in the manufacturing, processing, treatment program design rehearsal and preoperative fabrication of substitutes. Bone replacement with good mechanical properties and biocompatibility could be acquired using different materials and manufacturing techniques for maxillofacial reconstruction. 3D printing technology allows the use of additional biological materials and promotes the scaffolding preparation for tissue-engineered bones. In this paper, the current research and development of 3D printing materials applied in maxillofacial bone defects at home and abroad were summarised, and the developing trend of 3D printing technology was prospected.

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    Application progress on free soft-tissue grafts harvested from palatal mucosa
    Wu Jielin,Gao Ying
    Int J Stomatol. 2020, 47 (6):  686-692.  DOI: 10.7518/gjkq.2020087
    Abstract ( 1102 )   HTML ( 16 )   PDF(pc) (7525KB) ( 414 )   Save

    The hard palate is a common site for soft-tissue augmentation procedures, which have been widely performed to increase width and thickness of keratinized tissue around teeth and implants. Surgeons have to assess the location of the greater palatine neurovascular bundle, attach great importance to the thickness and histological composition of the grafts, and maintain their post-operative stabilization to achieve improved clinical performance. To guide clinical practices, our review summarizes relevant knowledge on the anatomy of the palate donor site, survival factors of the free soft-tissue grafts and their clinical applications.

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    Etiology and progress in the therapy of drug-induced gingival enlargement
    Li Yan,Meng Chenda,Xu Quanchen
    Int J Stomatol. 2020, 47 (6):  693-698.  DOI: 10.7518/gjkq.2020097
    Abstract ( 2264 )   HTML ( 192 )   PDF(pc) (5578KB) ( 1375 )   Save

    Drug-induced gingival enlargement (DIGE) refers to gingival fibrosis hyperplasia and volume enlargement caused by long-term use of certain drugs. DIGE can cause serious damage to the oral health of patients. Its etiology is unclear, and treatment is difficult. This article will discuss the research progress of the etiology of DIGE from five aspects: inflammation, the Wnt/β-catenin signaling pathway, epithelial-mesenchymal transition, integrin, and matrix metalloproteinase. Therapeutic progress is reviewed from four aspects of non-surgical treatment, surgical treatment, drug therapy and adjuvant therapy to provide a certain reference value for subsequent research and treatment.

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    Research progress on the root canal morphology of maxillary permanent molars by using cone-beam computed tomography
    Zhu Hualing,Yan Yujia,Zou Ling
    Int J Stomatol. 2020, 47 (6):  699-705.  DOI: 10.7518/gjkq.2020109
    Abstract ( 699 )   HTML ( 16 )   PDF(pc) (6812KB) ( 162 )   Save

    The complexity of the root and root canal anatomical morphology, high incidence of variation, and high root canal treatment rate of maxillary permanent molars render the latter a popular focus of clinical research. Cone-beam computed tomography (CBCT) has high resolution and affords vivid three-dimensional images, thereby enabling accurate studies of the root canal system. In this work, research progress on the root and canal anatomical morphology of maxillary permanent molars in different countries and races using CBCT was reviewed to provide a reliable basis for relevant clinical work. The incidence and symmetry of different root and root canal morphologies and their relationships with gender were also summarized.

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    Research progress of host modulation therapy in the treatment of periodontal diseases
    Chen Liang,Ding Yi,Meng Shu
    Int J Stomatol. 2020, 47 (6):  706-710.  DOI: 10.7518/gjkq.2020107
    Abstract ( 730 )   HTML ( 18 )   PDF(pc) (5032KB) ( 218 )   Save

    Host modulation therapy (HMT) is a therapeutic concept that treats inflammatory diseases by modulating host immune inflammatory responses to reduce tissue destruction. HMT has been used to treat osteoporosis and arthritis, and its application in stomatology has attracted widespread attention in recent years. This article reviews the current research progress of host-modulating drugs in the field of periodontal therapy, mainly including tetracycline drugs, non-steroidal- anti-inflammatory drugs, bisphosphonates, pro-inflammatory cytokine antagonists, and lipoxins.

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    Research progress on the effect of root canal sealers on root fracture resistance
    Ning Chenxi,Li Xia
    Int J Stomatol. 2020, 47 (6):  711-716.  DOI: 10.7518/gjkq.2020101
    Abstract ( 2063 )   HTML ( 453 )   PDF(pc) (6036KB) ( 1593 )   Save

    Root fracture is one of the most serious complications of root canal treatments. Cutting tooth tissue during root canal treatments, using sodium hypochlorite solution, and applying pressure on the wall of the root canal during filling can increase the risk of root fracture. Current research showed that the adhesive strength of root canal sealers with dentin and gutta-percha can affect the fracture resistance of roots to some extent. Several root canal sealers, such as zinc oxide-eugenol-based, glass ionomer-based, resin-based, calcium silicate-based, and silicon-based sealers, are clinically used. The bonding strengths of different types of sealers to dentin and gutta-percha are different. Their impacts on the fracture resistance of root are also different. This article reviews the effect of different root canal sealers on the fracture resistance of roots to provide a basis for a clinical choice of suitable root canal sealers.

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    Research progress on the pathogenesis of medication-related osteonecrosis of the jaw
    Guo Zhiyong,Liu Jiyuan,Li Chunjie,Tang Xiufa
    Int J Stomatol. 2020, 47 (6):  717-724.  DOI: 10.7518/gjkq.2020106
    Abstract ( 1965 )   HTML ( 220 )   PDF(pc) (7781KB) ( 1540 )   Save

    Medication-related osteonecrosis of the jaw (MRONJ) is a severe bone disease unique to the jaw. It is closely related to antiresorptive drugs and antiangiogenic drugs, such as bisphosphonates and denosumab. The effect of current treatments on MRONJ is limited. Despite the rapid progression of the pathogenesis of MRONJ, the specific mechanism remains unclear. The hypotheses of MRONJ mainly include disrupted bone remodeling, suppression of angiogenesis, oral microbial infection, inhibition of immunity, toxicity of soft tissue, and microcracks. The pathogenesis of MRONJ may be influenced by multiple factors. The purpose of the current review is to summarize recent progress on MRONJ research.

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    Research progress and consensus of experts on the therapy of peri-implant diseases
    Zheng Guiting,Xu Yan,Wu Mingyue
    Int J Stomatol. 2020, 47 (6):  725-731.  DOI: 10.7518/gjkq.2020103
    Abstract ( 1706 )   HTML ( 220 )   PDF(pc) (6897KB) ( 2095 )   Save

    Owing to the development of implant-repairing techniques and materials and improvement in people’s living standard, the use of implants to replace missing teeth has considerably increased. The gradual increase in the incidence of peri-implant diseases has drawn attention. In recent years, therapeutic principles and treatment procedures for peri-implant diseases have mostly come into agreement, and novel treatment concepts and therapeutic methods have been proposed. This review explores the development of the expert consensus and methods for treating peri-implant diseases.

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    Research progress on tea polyphenols in dentin adhesion
    Liu Enyan,Li Mingyun
    Int J Stomatol. 2020, 47 (6):  732-738.  DOI: 10.7518/gjkq.2020089
    Abstract ( 878 )   HTML ( 16 )   PDF(pc) (6614KB) ( 197 )   Save

    The technology of tooth bonding is improved for many generations and is widely used in the field of oral defect repair. The dental adhesive technique can meet the conservative clinical treatment requirements, but the issue that the dentin-adhesive interface deteriorates over time remains. The structure of tea polyphenols contains multiple phenolic hydroxyl groups, which easily form hydrogen bonds with dentin collagen molecules, thereby improving the durability of the resin dentin adhesion repair. In recent years, the effects of the addition of epigallocatechin-3-gallate (EGCG), the main active substance in tea polyphenols, on the dentin bonding effect and the mechanism of action have become the research focus. In this paper, the role of EGCG in the dentin bonding process and the corresponding mechanism are reviewed.

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    Research status and application development of three-dimensional cephalometry
    Zhang Zihan,Xiong Xin,Wang Jun
    Int J Stomatol. 2020, 47 (6):  739-744.  DOI: 10.7518/gjkq.2020092
    Abstract ( 1373 )   HTML ( 47 )   PDF(pc) (5894KB) ( 524 )   Save

    Cephalometry is an important analytic measurement for orthodontic diagnosis and treatment and has gradually evolved from plane to stereoscopy with the development of three-dimensional imaging technology. In three-dimensional cephalometry, the cone beam computed tomography (CBCT) craniofacial images of patients are measured and analyzed with three-dimensional analytic software. Compared with traditional two-dimensional cephalometry, three-dimensional cephalometry has overwhelming advantages on image definition and accuracy and thus has become a research focus. This review summarized the progress on three-dimensional cephalometry in five aspects: methods for identifying landmarks, landmarks, and reference planes; measurements and analyses; superimposition; advantages and research status; and future prospects.

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