中华口腔医学杂志最新文献

{"title":"[Analysis of detection accuracy rate of dental esthetic defects under different visual angles].","authors":"X R Shi, J H Zhang, Y S Wu, F Liu","doi":"10.3760/cma.j.cn112144-20260421-00245","DOIUrl":"https://doi.org/10.3760/cma.j.cn112144-20260421-00245","url":null,"abstract":"<p><p><b>Objective:</b> To investigate the effect of different visual angles on the accuracy of esthetic defect detection in the dental esthetic zone, clarify the differences in detection accuracy across different tooth positions, esthetic defect types and professional backgrounds of dentists, so as to provide reference for standardized clinical evaluation of dental esthetics. <b>Methods:</b> A total of 114 licensed dentists who participated in various continuing education programs at Peking University School and Hospital of Stomatology from January to December 2025 was enrolled as research subjects. They were divided into the prosthodontics and orthodontics group (<i>n</i>=49) and the other specialties group (<i>n</i>=65). The baseline maxillary anterior teeth photograph from a 26-year-old female volunteer was set as the control. Eleven images with 4 types of esthetic defects (incisal edge position, gingival margin position, tooth long axis and crown width-to-length ratio) were generated, bringing the total number of study images to 12. After rotation at 0°, 90° and 180°, 36 study images were obtained in total. The images were presented to the subjects via slides, with each image shown for 8s. Two evaluation indicators were adopted:defect detection rate and detection accuracy rate. Subjects were required to determine whether there was a esthetic defect in the image and identify the specific type of defect. A correct detection was defined as accurate judgment of both the existence of the defect and the defect type. The values of the two indicators were calculated, and data were analyzed using the chi-square test with SPSS 27.0 software. <b>Results:</b> The detection rate of aesthetic defects among the 36 images ranged from 23.7% (27/114) to 100.0% (114/114), and the accuracy rate ranged from 5.3% (6/114) to 79.8% (91/114). The difference in detection accuracy among different visual angles was statistically significant: the 0° angle had the highest detection accuracy [52.2% (714/1 368)], followed by the 180° angle [45.1% (617/1 368)], and the 90° angle had the lowest accuracy [26.8% (366/1 368)]. For different tooth positions, the detection accuracy of esthetic defects in central incisors [54.2% (741/1 368)] was significantly higher than that in other positions [34.9% (956/2 736)]. The differences in defect detection accuracy under different visual angles were all statistically significant for incisal edge position, gingival margin position, tooth long axis and crown width-to-length ratio (all <i>P</i><0.017). There was no statistically significant difference in defect detection accuracy between the prosthodontics and orthodontics group and the other specialties group (<i>P</i>>0.05). <b>Conclusions:</b> Visual angle significantly affects the detection accuracy rate of dental esthetic defects, and the 0° angle is more conducive to the identification of aesthetic defects. Tooth position and defect type also have an impact on the detection accuracy ","PeriodicalId":23965,"journal":{"name":"中华口腔医学杂志","volume":"61 9","pages":"1323-1329"},"PeriodicalIF":0.0,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148867025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Preliminary observation of the impact by alveolar ridge preservation on maxillary sinus in patients with severe periodontitis: a retrospective study].","authors":"H Y Chen, J Q Deng, P Y Chen, Z Yang, Y C Li, Y P Pan","doi":"10.3760/cma.j.cn112144-20251209-00497","DOIUrl":"10.3760/cma.j.cn112144-20251209-00497","url":null,"abstract":"<p><p><b>Objective:</b> To investigate the ameliorative effect of alveolar ridge preservation (ARP) on maxillary sinus mucosal thickening caused by severe periodontitis, as well as its positive significance in preventing the occurrence of pathological maxillary sinus pneumatization. <b>Methods:</b> This retrospective study included 49 patients with severe periodontitis who underwent unilateral ARP of maxillary molar at the Department of Periodontology, School and Hospital of Stomatology, China Medical University, between April 2020 and April 2025. A total of 98 sites were analyzed, including 49 ARP sites and 49 contralateral control sites. According to the completeness of follow-up cone beam CT (CBCT) data and the study objectives, the analysis was divided into two parts: ①Longitudinal study: 31 patients with complete preoperative and 6-month postoperative CBCT records were included (31 ARP sites) to evaluate changes in residual alveolar bone height and maxillary sinus vertical height before and after surgery. Among these, 18 sites with odontogenic maxillary sinusitis (OMS) at baseline were further analyzed for changes in Schneiderian membrane thickness. ②Cross-sectional study: 40 patients with complete 6-month postoperative CBCT records were included (80 sites in total). The maxillary sinus vertical height at ARP sites was compared with that at contralateral naturally healed post-extraction sites (12 pairs) or contralateral healthy natural tooth sites (28 pairs). <b>Results:</b> In the longitudinal analysis, the vertical alveolar bone height at ARP sites significantly increased from 3.60(1.77, 5.82) mm at baseline to 6.84(4.96, 9.46) mm at 6 months postoperatively (<i>n</i>=31, <i>Z</i>=4.74, <i>P</i><0.05), whereas no significant change was observed in maxillary sinus vertical height (<i>P</i>>0.05). At sites with OMS, Schneiderian membrane thickness significantly decreased from 5.13 (3.17, 10.90) mm preoperatively to 1.19 (0.57, 2.09) mm at 6 months postoperatively (<i>n</i>=18, <i>Z</i>=-3.62, <i>P</i><0.05). In the cross-sectional analysis, the maxillary sinus vertical height at ARP sites [33.69 (28.97, 36.70) mm] was significantly lower than that at contralateral naturally healed post-extraction sites [36.45(32.76, 39.08) mm] (<i>n</i>=12, <i>Z</i>=2.98, <i>P</i><0.01), while with no significant difference compared to contralateral healthy natural tooth sites (<i>P</i>>0.05). After adjustment for age and sex, maxillary sinus vertical height was negatively correlated with residual alveolar bone height (<i>r</i>_partial=-0.448, <i>P</i><0.001). <b>Conclusions:</b> ARP may help reduce Schneiderian membrane thickening associated with severe periodontitis and may have potential clinical value in limiting post-extraction maxillary sinus pneumatization.</p>","PeriodicalId":23965,"journal":{"name":"中华口腔医学杂志","volume":"61 8","pages":"1178-1186"},"PeriodicalIF":0.0,"publicationDate":"2026-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148631698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Research progress in the application of artificial intelligence in three-dimensional tooth shape completion].","authors":"Y P Mei, Y Li, X L Ni, Y Yang, H Q Tang, S R Zhao, Y Q Zhang, X Q Liu","doi":"10.3760/cma.j.cn112144-20251217-00519","DOIUrl":"10.3760/cma.j.cn112144-20251217-00519","url":null,"abstract":"<p><p>Three-dimensional (3D) tooth shape completion refers to the process of predicting and reconstructing the intact tooth morphology based on defective 3D inputs obtained from intraoral or laboratory scanner. The generated result serves as a digital diagnostic wax-up, offering clinicians a visualized treatment target and outcome preview, thereby aiding in clinical diagnosis and treatment planning. This review summarizes the current applications of artificial intelligence in 3D tooth shape completion, focusing on major research progress in commonly used algorithmic models, datasets, ground truth acquisition, control model configuration, and evaluation metrics. It aims to provide guidance for future related studies.</p>","PeriodicalId":23965,"journal":{"name":"中华口腔医学杂志","volume":"61 8","pages":"1235-1242"},"PeriodicalIF":0.0,"publicationDate":"2026-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148631766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Comparison of treatments for osteoradionecrosis of the jaw and medication-related osteonecrosis of the jaw].","authors":"Z Y Wang, Y He","doi":"10.3760/cma.j.cn112144-20260401-00203","DOIUrl":"10.3760/cma.j.cn112144-20260401-00203","url":null,"abstract":"<p><p>Osteonecrosis of the jaw (ONJ) is an inflammatory and necrotic disease affecting the jawbones. The most prevalent forms include osteoradionecrosis of the jaw (ORNJ) following radiotherapy for head and neck malignancies, and medication-related osteonecrosis of the jaw (MRONJ) triggered by long-term use of antiresorptive, antiangiogenic, or corticosteroid agents. Although clinicians have explored diverse modalities, including pharmacotherapy, hyperbaric oxygen, and surgical intervention and several international guidelines have been published, a universal \"gold standard\" for ONJ management remains elusive. Significant challenges persist regarding the selection of treatment modalities for different disease stages, the timing of surgical intervention, and the restoration of jaw function. This review focuses on these clinical dilemmas, summarizes recent therapeutic advances to provide a refined reference for clinical decision-making.</p>","PeriodicalId":23965,"journal":{"name":"中华口腔医学杂志","volume":"61 8","pages":"1121-1126"},"PeriodicalIF":0.0,"publicationDate":"2026-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148631738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Research progress in the bidirectional relationship between oral infectious diseases and mental health issues].","authors":"J M Yang, M L Yuan, Y Y Zhang, Y Chen, X Qu","doi":"10.3760/cma.j.cn112144-20251031-00437","DOIUrl":"10.3760/cma.j.cn112144-20251031-00437","url":null,"abstract":"<p><p>Infectious oral diseases represent the most prevalent categories of oral conditions, including dental caries, periodontitis, periapical lesions, and pericoronitis. Their bidirectional relationship with mental health has emerged as a critical interdisciplinary research frontier. This paper integrates epidemiological findings and molecular mechanism evidence to analyze the significant comorbidity and correlation characteristics between infectious oral diseases such as caries and periodontitis, and psychological disorders including depression and anxiety. Oral diseases not only directly impair mental well-being through pain, functional impairment, and social anxiety, but also induce systemic inflammatory responses that disrupt the blood-brain barrier, activate microglia, and alter neurotransmitter metabolism, thereby contributing to functional dysregulation within emotional regulatory centers. The dysbiosis of the oral microbiota caused by infectious oral diseases plays a central role in the vicious cycle of \"oral infection-mental health disorders\" through the\"oral-gut-brain axis\", inflammation-mediated neuroimmune cascades, and hypothalamic-pituitary-adrenal axis dysregulation. Meanwhile, mental disorders exacerbate oral microbial imbalance and tissue destruction through poor oral hygiene behaviors, xerostomia induced by psychotropic medications, and stress-related neuroendocrine alterations. This paper advocates for synergistically integrate oral clinical interventions with mental health improvement strategies, and for the development of microbiome-targeted precision modulation approaches. It further proposes an integrated health management paradigm that bridges dentistry and psychiatry, providing both theoretical foundations and practical pathways to transcend traditional disciplinary boundaries and achieve holistic oral-mental co-management.</p>","PeriodicalId":23965,"journal":{"name":"中华口腔医学杂志","volume":"61 8","pages":"1243-1250"},"PeriodicalIF":0.0,"publicationDate":"2026-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148631743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Interpretation of the latest Sixth Conference of the Parties (COP-6) decision of the Minamata Convention on Mercury].","authors":"Y Si, L Yue","doi":"10.3760/cma.j.cn112144-20260203-00088","DOIUrl":"10.3760/cma.j.cn112144-20260203-00088","url":null,"abstract":"<p><p>The Sixth Conference of the Parties (COP-6) to the Minamata Convention on Mercury-a treaty administered by the United Nations Environment Programme adopted a decision to phase out the manufacture, import, or export of dental amalgam by 2034. This article reviews the background of the Minamata Convention and China's implementation process, with a focus on analyzing the policy measures taken by China to phase down dental amalgam, the promotion and application of clinical alternative materials (such as composite resins), and the corresponding adjustments in dental education. At present, the usage rate of dental amalgam in oral clinical practice of China has dropped significantly, and composite resin has become the mainstream restorative material. China has provided practical references for global mercury pollution control through multi-departmental collaboration, scientific research support and professional training.</p>","PeriodicalId":23965,"journal":{"name":"中华口腔医学杂志","volume":"61 8","pages":"1107-1112"},"PeriodicalIF":0.0,"publicationDate":"2026-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148631692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[A retrospective study of pedicled flaps for repair of oral mucosal defects in patients with medication-related osteonecrosis of the jaw].","authors":"D D Wang, Y W Liu, J Wang, Y X Guo, D Xu, Z H Tang, C Huang, C L Zong, L Tian","doi":"10.3760/cma.j.cn112144-20260408-00222","DOIUrl":"10.3760/cma.j.cn112144-20260408-00222","url":null,"abstract":"<p><p><b>Objective:</b> To investigate the clinical efficacy of pedicled flaps for repairing oral mucosa defects in medication-related osteonecrosis of the jaw (MRONJ), and to analyze the indications for different types of pedicled flaps. <b>Methods:</b> The clinical data of 158 MRONJ patients who met the inclusion criteria and were admitted to the Department of Maxillofacial Trauma and Orthognathic Surgery, Hospital of Stomatology, Air Force Medical University from January 2019 to December 2024 were retrospectively analyzed, including 74 males (46.8%) and 84 females (53.2%).The age was (59.2±10.7) years (range, from 20 to 87 years old). According to the method of soft tissue repair, the patients were divided into direct suture group (61 cases) and pedicled tissue flap group (97 cases, including 80 cases of buccal fat pad flap and 17 cases of submental island flap). The rate of secondary operation was compared between the two groups. Multivariate binary Logistic regression and subgroup analysis were used to evaluate the efficacy and influencing factors of pedicled tissue flaps, and the comparison between the buccal fat pad flap and submental island flap was performed. <b>Results:</b> The median follow-up time was 36 months. Univariate analysis showed that the secondary operation rate was 68.9% (42/61) in the direct suture group, which was significantly higher than 16.5% (16/97) in the pedicled tissue flap group (<i>P</i><0.001). After adjusting for confounding factors such as age and lesion location, multivariate Logistic regression analysis showed that pedicled tissue flap was an independent protective factor against the risk of secondary surgery (<i>OR</i>=0.049, <i>P</i><0.001). Stage 3 disease was an independent risk factor for secondary surgery (<i>OR</i>=8.455, <i>P=</i>0.002). Subgroup analysis showed that the secondary operation rate of pedicled tissue flap was significantly lower than that of direct suture in stage 3 group, mandibular group,<65 years group, male group and female group (all <i>P</i><0.05). There was no significant difference among stage 2 group, maxillary group and ≥65 years group (all <i>P</i>>0.05), but the trend of protection was the same. The secondary operation rate was 17.5% (14/80) in the buccal fat pad flap group and 2/17 in the submental island flap group. There was no significant difference between the two groups (<i>P</i>=0.730). <b>Conclusions:</b> The use of pedicled tissue flap for repairing oral mucosal wounds can significantly reduce the risk of secondary surgery for MRONJ, and the effect is superior to direct suture. Buccal fat pad flap is the first choice for maxillary and retromolar mucosal defects, and submental island flap can be used for large mandibular mucosal defects.</p>","PeriodicalId":23965,"journal":{"name":"中华口腔医学杂志","volume":"61 8","pages":"1150-1157"},"PeriodicalIF":0.0,"publicationDate":"2026-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148631745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Diffuse sclerosing osteomyelitis of the jaw: research advances and treatment strategies].","authors":"G Q Zhang, J G An","doi":"10.3760/cma.j.cn112144-20260207-00103","DOIUrl":"10.3760/cma.j.cn112144-20260207-00103","url":null,"abstract":"<p><p>Diffuse sclerosing osteomyelitis of the jaw (DSO) is a rare non-suppurative inflammatory bone disease of unknown etiology, characterized by a chronic course, recurrent pain, and diffuse jawbone sclerosis. Diagnosis is challenging, and conventional surgical and anti-infective therapies have limited efficacy with high recurrence. Recent studies reveal that DSO is closely associated with synovitis-acne-pustulosis-hyperostosis-osteitis syndrome. The core mechanisms involves autoinflammatory bone-immune imbalance, particularly dysregulation of the receptor activator of nuclear factor-κB (NF-κB) ligand/receptor activator of NF-κB/osteoprotegerin (RANKL/RANK/OPG) signaling pathway. Consequently, the treatment strategy for DSO has fundamentally shifted from surgery and anti-infective drugs to a precision medicine approach with bisphosphonates, as the cornerstone,and expanded to include denosumab, tumor necrosis factor-α inhibitors, and JAK inhibitors. This article systematically reviews the etiology, diagnosis, key differential diagnoses, and recent advances in pharmacotherapy, and proposes a stepped treatment algorithm.</p>","PeriodicalId":23965,"journal":{"name":"中华口腔医学杂志","volume":"61 8","pages":"1113-1120"},"PeriodicalIF":0.0,"publicationDate":"2026-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148631747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Practical significance of basic training in periodontal diagnosis and treatment: the essential pathway for the prevention and control of periodontal diseases].","authors":"Y P Wei, W J Hu, J S Zhong","doi":"10.3760/cma.j.cn112144-20251011-00396","DOIUrl":"10.3760/cma.j.cn112144-20251011-00396","url":null,"abstract":"<p><p>Solid fundamental skills in periodontal diagnosis and treatment constitute the cornerstone of professional development and clinical competence for every dentist, particularly for periodontists. This article highlights the practical significance and urgency of strengthening such fundamental training within the current landscape of oral healthcare. These essential competencies, mandatory for both periodontists and general dentists, include periodontal examination, manual supragingival scaling, subgingival scaling and root planing, ultrasonic instrumentation, as well as basic periodontal surgical procedures such as gingivectomy and periodontal flap surgery. Proficiency in these skills is crucial for preventing periodontal diseases, arresting disease progression, and achieving long-term clinical stability. Furthermore, this article identifies seven common cognitive and operational misconceptions in current periodontal practice and proposes corresponding strategies. Neglecting fundamental skills while blindly pursuing advanced devices, complex procedures, or techniques absence of scientific evidence equates to abandoning the foundation of periodontal therapy. Therefore, continuous enhancement and innovating fundamental skills training in undergraduate, postgraduate, and dental continuing education hold strategic importance for improving the overall standard of periodontal disease prevention and treatment in China.</p>","PeriodicalId":23965,"journal":{"name":"中华口腔医学杂志","volume":"61 8","pages":"1127-1133"},"PeriodicalIF":0.0,"publicationDate":"2026-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148631187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Research progress in the pathogenesis of medication-related osteonecrosis of the jaw based on immune-vascular coupling dysfunction].","authors":"Z S Jiang, L Ye, Z W Cao, C Z Zhao, N Zhang, J Y Liu, J Pan","doi":"10.3760/cma.j.cn112144-20260318-00176","DOIUrl":"10.3760/cma.j.cn112144-20260318-00176","url":null,"abstract":"<p><p>The pathogenesis of medication-related osteonecrosis of the jaw (MRONJ) is complex, and the traditional bone remodeling inhibition theory cannot fully explain its pathological evolution. From a microenvironmental perspective, this review systematically reviews the critical role of \"immune-vascular coupling\" dysfunction in MRONJ. Long-term exposure to anti-resorptive drugs induces phenotypic polarization imbalance, metabolic disorders, and impaired efferocytosis in local macrophages, triggering persistent inflammation. Simultaneously, these drugs not only exert direct toxicity on endothelial cells but also disrupt vascular regeneration and drainage through abnormal intercellular communication. The combination of immune dysregulation and vascular degeneration ultimately leads to the failure of coordinated soft and hard tissue repair. This article aims to provide a systematic reference for the mechanistic understanding and targeted prevention and treatment of MRONJ.</p>","PeriodicalId":23965,"journal":{"name":"中华口腔医学杂志","volume":"61 8","pages":"1227-1234"},"PeriodicalIF":0.0,"publicationDate":"2026-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148631690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}