Hellenic Archives of Oral & Maxillofacial Surgery最新文献

筛选
英文 中文
Hayes Martin: The leading figure of Head and Neck Surgery 海斯-马丁:头颈外科的领军人物
Hellenic Archives of Oral & Maxillofacial Surgery Pub Date : 2024-04-01 DOI: 10.54936/haoms2515156
A. Mylonas
{"title":"Hayes Martin: The leading figure of Head and Neck Surgery","authors":"A. Mylonas","doi":"10.54936/haoms2515156","DOIUrl":"https://doi.org/10.54936/haoms2515156","url":null,"abstract":"","PeriodicalId":164809,"journal":{"name":"Hellenic Archives of Oral & Maxillofacial Surgery","volume":"163 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140756331","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}
引用次数: 0
Alternative surgical restoration of aesthetic defect during superficial parotidectomy – Case report 浅表腮腺切除术中修复美学缺陷的替代手术--病例报告
Hellenic Archives of Oral & Maxillofacial Surgery Pub Date : 2024-04-01 DOI: 10.54936/haoms254349
Nikolaos Kechagias, Elias Tourtounis
{"title":"Alternative surgical restoration of aesthetic defect during superficial parotidectomy – Case report","authors":"Nikolaos Kechagias, Elias Tourtounis","doi":"10.54936/haoms254349","DOIUrl":"https://doi.org/10.54936/haoms254349","url":null,"abstract":"Tumors in the parotid gland, which is the largest salivary gland, could appear as a swelling in the cheek area or in the area in front of and below the earlobe. The majority are benign tumors. In all cases, removal of the tumor by parotidectomy is the main option. In the majority of these operations, postoperatively a defect remains in the lateral region of the face after the removal of the tumor. Many solutions have been proposed internationally to treatment this aesthetic defect. In this study, a proposal is presented to use part of the remaining parotid tissue, to restore the defect that appears after the removal of the tumor and the preparation of the facial nerve.","PeriodicalId":164809,"journal":{"name":"Hellenic Archives of Oral & Maxillofacial Surgery","volume":"310 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140776584","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}
引用次数: 0
Dental Management of patient with Parkinson’s Disease 帕金森病患者的牙科治疗
Hellenic Archives of Oral & Maxillofacial Surgery Pub Date : 2024-04-01 DOI: 10.54936/haoms2511730
Alexios Liosatos
{"title":"Dental Management of patient with Parkinson’s Disease","authors":"Alexios Liosatos","doi":"10.54936/haoms2511730","DOIUrl":"https://doi.org/10.54936/haoms2511730","url":null,"abstract":"Background: Parkinson’s disease (PD) is a chronic progressive neurodegenerative disorder. This disease affects about 1 in 1000 people in the general population and 1% of the over 60 age group. The main features of the disease are: resting tremor, bradykinesia, postural instability, muscle rigidity and inexpressible face (mask-like face). People with PD face a series of pathological manifestations from the oromaxillofacial region related to the disease, while some of the drugs used to treat PD also lead to adverse effects from the oral cavity. Purpose: The dentist should be able to recognize the basic signs and symptoms of the disease, its basic oral manifestations and the basic dental management protocols of patients with PD. This review aims to contribute in this direction. Method: In pubmed database we searched with keywords “dental and Parkinson’s disease”, “Parkinson disease and dental management”, ‘Parkinson and periodontal’, “oral hygiene and Parkinson disease’, “periodontitis and Parkinson’s disease”. We concluded that 141 papers were to be used in our review. We also used Little’s and Scully’s books on the medically compromised patient, as well as Dougall’s series of articles for disabled patients. Last, we used few website links of official dental sites. Conclusion: PD patients may suffer from a multitude of pathological manifestations from the oral-maxillofacial area, while they need special dental management due to motor, mental and autonomic neural system disorders. The insufficient experience and training of the majority of dentists in treating patients with PD is given. The dental community in collaboration with the medical community and the State is important to contribute to the improvement of the oral health of PD patients, by educating patients and dentists.","PeriodicalId":164809,"journal":{"name":"Hellenic Archives of Oral & Maxillofacial Surgery","volume":"32 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140797492","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}
引用次数: 0
Recent advances in orthognathic surgery and modern diagnostic techniques 正颌外科手术和现代诊断技术的最新进展
Hellenic Archives of Oral & Maxillofacial Surgery Pub Date : 2024-04-01 DOI: 10.54936/haoms251516
Nikolaos Kolomvos, Anna-Maria Chronopoulou, Christos Perisanidis
{"title":"Recent advances in orthognathic surgery and modern diagnostic techniques","authors":"Nikolaos Kolomvos, Anna-Maria Chronopoulou, Christos Perisanidis","doi":"10.54936/haoms251516","DOIUrl":"https://doi.org/10.54936/haoms251516","url":null,"abstract":"New technological tools are increasingly being applied in orthognathic surgery. Advanced techniques of imaging, diagnosis and treatment planning development, as well as simulation, guidance and evaluation of the treatment outcome are gradually taking the place of conventional techniques, enabling three-dimensional (3D) digital planning and personalized treatment of craniofacial deformities. Conventional and advanced three-dimensional techniques, such as three-dimensional ultrasound imaging (3D U/S), three-dimensional magnetic resonance imaging (3T-MRI), three-dimensional computed tomography (CT) and cone beam computed tomography (CBCT) imaging, as well as combinations of these techniques, are classified as modern technological tools, while robotic surgery and four-dimensional video stereophotogrammetry have already begun to find clinical application. In conclusion, advances in diagnostic and planning techniques in orthognathic surgery present many preoperative, intraoperative and postoperative advantages, significantly reducing the chances of complications and providing safety, accuracy and a high level of medical care. The aim of this literature review is to collect, present and evaluate new data and contemporary diagnostic methods in the field of orthognathic surgery.","PeriodicalId":164809,"journal":{"name":"Hellenic Archives of Oral & Maxillofacial Surgery","volume":"44 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140792357","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}
引用次数: 0
Antrolith: radiological diagnosis and surgical treatment – presentation of clinical cases 抗结石:放射学诊断和手术治疗--临床病例介绍
Hellenic Archives of Oral & Maxillofacial Surgery Pub Date : 2024-04-01 DOI: 10.54936/haoms2513141
Zois-Panagiotis Vlachopanos, Christos Impas, Athanasios Venetis, Evangelos Liapis, Chrysi Papadeli, A. Delantoni
{"title":"Antrolith: radiological diagnosis and surgical treatment – presentation of clinical cases","authors":"Zois-Panagiotis Vlachopanos, Christos Impas, Athanasios Venetis, Evangelos Liapis, Chrysi Papadeli, A. Delantoni","doi":"10.54936/haoms2513141","DOIUrl":"https://doi.org/10.54936/haoms2513141","url":null,"abstract":"Introduction: Antrolith is a pathological calcified mass located in the paranasal sinuses, commonly in the maxillary sinus. When it is found in the vicinity or into the nasal cavity, it is also called rhinolith. In most of the cases, antroliths are incidentally identified through dental patients’ radiological examination. This fact underlines the need of antroliths’ detection in radiographs even by the general dentist. Objective: This paper aims to discuss the clinical and radiological diagnosis of antrolith, as well as its therapeutic methods, through the presentation of two clinical cases. Materials – Methods: Clinical cases, diagnosed with dental panoramic radiographs, radiographs of paranasal sinuses (Water’s view) and cone beam computed tomography (CBCT), are presented. Moreover, there has been conducted a review of the recent literature with scientific papers published in databases PubMed and Google Scholar. Results: Antrolith is usually an asymptomatic clinical feature, but painful symptomatology is rarely observed. Radiologically, it is mainly diagnosed with accuracy using orthopantomography and CBCT. As a pathological mass, antrolith should be differentiated from dental dysplasias, inflammatory calcifications, foreign bodies, even neoplasms in case of sizeable antroliths. The treatment choices of antroliths, depending on the severity of every clinical case, include frequent medical observation without any intervention or surgical excision techniques, most commonly the endoscopic sinus surgery or the removal through intraoral access. This article refers to two clinical cases of antroliths, one asymptomatic and one painful case, with all the diagnostic and management methodology being discussed. Conclusions: The radiological diagnosis of antroliths in conjunction with the endoscopic sinus surgery for its removal provide with the opportunity to treat and relieve patients with painful symptomatology. It is important not to be missed by the general dentist, as it may appear incidentally when evaluating panoramic radiographs. The assessment of antroliths is crucial for the differential diagnosis and its therapeutic management requires cooperation with a specialist.","PeriodicalId":164809,"journal":{"name":"Hellenic Archives of Oral & Maxillofacial Surgery","volume":"42 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140783582","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}
引用次数: 0
Editorial, volume 25, issue 1 社论,第 25 卷第 1 期
Hellenic Archives of Oral & Maxillofacial Surgery Pub Date : 2024-04-01 DOI: 10.54936/haoms25114
Athanassios Kyrgidis
{"title":"Editorial, volume 25, issue 1","authors":"Athanassios Kyrgidis","doi":"10.54936/haoms25114","DOIUrl":"https://doi.org/10.54936/haoms25114","url":null,"abstract":"","PeriodicalId":164809,"journal":{"name":"Hellenic Archives of Oral & Maxillofacial Surgery","volume":"52 21","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140771110","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}
引用次数: 0
Critical points in MRI examination of patients with anterior disc displacement 前盘移位患者MRI检查的关键点
Hellenic Archives of Oral & Maxillofacial Surgery Pub Date : 2022-12-01 DOI: 10.54936/haoms233159169
Ch. Papadeli, C. Kouskouras, G. Venetis, Adamantia Filippou
{"title":"Critical points in MRI examination of patients with anterior disc displacement","authors":"Ch. Papadeli, C. Kouskouras, G. Venetis, Adamantia Filippou","doi":"10.54936/haoms233159169","DOIUrl":"https://doi.org/10.54936/haoms233159169","url":null,"abstract":"Objectives: The aim of this study is to de- termine the importance of the distance of tubercle head displacement when using MRI to investigate an- terior disc displacement of the CSF disc and to study when and under what conditions the term repositioning should be applied Material and method: MRI images of anterior disc mis- alignment are presented, where an attempt is made to staging the misalignment and articular disc reset. The statistical sample was patients with symptoms of pain and TMJ dysfunction, in whom anterior misalign- ment was diagnosed clinically and confirmed by MRI ex- amination in the closed mouth position. Results: The distance travelled by the tubercle head within the joint is influenced by the acquisition technique and this is crucial for the diagnosis Conclusions: The importance of condylar head move- ment is great in the study of temporomandibular joint dysfunctions and should always be evaluated in con- junction with the position of the articular disc and its morphology. When ‘reversion’ is recorded as any case where the tu- bercle head in a position of maximum opening meets the disc, regardless of the distance from the articular germ, what is interpreted as a reversion conceals the extent of the joint pathology, because it is not a restora- tion of the normal disc-condyle-physeal relationship, but a situation that is detrimental to the morphology of the disc and an intermittent opening with obstacles. Hypermobility and hypermobility often coexist with anterior disc misalignment, evading diagnosis even with MRI imaging due to the application of the passive-open- ing technique. Static imaging with active opening is currently the method of choice that provides the necessary information both for the range of tuberosity movement and for the study of disc and posterior tissue morphology.","PeriodicalId":164809,"journal":{"name":"Hellenic Archives of Oral & Maxillofacial Surgery","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126841833","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}
引用次数: 0
Thyroglossal duct cysts: experience from a series of cases treated in the Oral and Maxillofacial Surgery Clinic of General Hospital “G.Papanikolaou’’ in Thessaloniki, Greece 甲状舌管囊肿:综合医院口腔颌面外科门诊治疗的一系列病例体会。希腊塞萨洛尼基的Papanikolaou
Hellenic Archives of Oral & Maxillofacial Surgery Pub Date : 2022-12-01 DOI: 10.54936/haoms2411524
T. Grivas, Ioannis Pappas, N. Pastelli, James Philip Skliris, Konstantinos Paraskevopoulos, Konstantinos Vaxtsevanos
{"title":"Thyroglossal duct cysts: experience from a series of cases treated in the Oral and Maxillofacial Surgery Clinic of General Hospital “G.Papanikolaou’’ in Thessaloniki, Greece","authors":"T. Grivas, Ioannis Pappas, N. Pastelli, James Philip Skliris, Konstantinos Paraskevopoulos, Konstantinos Vaxtsevanos","doi":"10.54936/haoms2411524","DOIUrl":"https://doi.org/10.54936/haoms2411524","url":null,"abstract":"SUMMARY: Thyroglossal duct cyst is the most common swelling of fetal origin in the cervix, located predominantly in the frontal neck area. The prevalence of the disease is 7%, while in bibliography there is some controversy regarding the age of diagnosis, since some authors find greater occurrence in children and others in adults.[1-3] Clinically, it usually appears as a mobile, painless mass without tension most commonly located below the hyoid bone (75% of the patients), but if inflammated, it can be accompanied by pain. The indicated therapeutic approach of thyroglossal duct cysts is surgical removal under general anesthesia according to Sistrunk technique, that ensures the full removal of the cyst’s wall including part of the hyoid bone body with which it is usually attached. The aim of the present study which was written based on SCARE 2020 protocol according to EQUATOR[4] is the presentation of a series of 5 cases which were surgically treated in the University Clinic of Oral and Maxillofacial Surgery of G.Papanikolaou General Hospital in a 2.5 years time frame(9/2019-2/2022). Four of the patients were men(80%) (mean age 50.5 years, ranging from 36 to 71 years old) and one was a 63 year old woman(20%). All of the patients presented in the outpatient unit of the clinic with a painless mobile neck mass, that appeared euthyroid from the laboratory tests. All of the patients underwent surgical removal of the thyroglossal duct cyst and part of the hyoid bone at the same time (Sistrunk procedure). No regression was noticed in the frequent postoperative follow-up. In conclusion, thyroglossal duct cyst is a clinically evident entity which although is more often diagnosed and treated surgically in childhood, it can also appear in adults. It may be complicated with inflammation and appear as a painful neck swelling. The treatment of choice is surgical removal according to Sistrunk procedure.","PeriodicalId":164809,"journal":{"name":"Hellenic Archives of Oral & Maxillofacial Surgery","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117314094","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}
引用次数: 0
Implant placement in the aesthetic zone: Long-term results. 美观区种植体放置:长期效果。
Hellenic Archives of Oral & Maxillofacial Surgery Pub Date : 2022-12-01 DOI: 10.54936/haoms241314
Despoina Gkouzoula, Spyridon Avgoustis, E. Vlachos, Aggeliki Lamprinoudi, I. Fourmousis
{"title":"Implant placement in the aesthetic zone: Long-term results.","authors":"Despoina Gkouzoula, Spyridon Avgoustis, E. Vlachos, Aggeliki Lamprinoudi, I. Fourmousis","doi":"10.54936/haoms241314","DOIUrl":"https://doi.org/10.54936/haoms241314","url":null,"abstract":"SUMMARY: Implant placement is considered to be a routine procedure for oral rehabilitation, in cases of tooth agenesia or tooth loss (due to factors such as periodontitis, trauma,caries). Dental implants’ position does not change over time due to the process of “osseointegration”. On the contrary, teeth follow craniofacial growth (in particular, orofacial and dentoalveolar growth) and move. The stomatognathic system undergoes changes in its vertical and horizontal dimensions after adulthood. Implant placement on the anterior maxilla is challenging for clinicians, because of continuous eruption of adjacent teeth, as well as, due to occurrence of occlusal changes. Long-term aesthetic complications, such as differences in incisal edges’ length, position of gingival margins and open contact points between implant restorations and adjacent teeth, should be taken into consideration. The aim of this study is to review literature concerning long-term complications after implant placement in the anterior maxilla. Furthermore, 2 case reports concerning aesthetic problems of implant restorations in the esthetic zone will be presented, together with their treatment procedure. Consequently, with time, implant restorations in the anterior maxilla present aesthetic complications of various degrees, which are in need of personalized treatment plan. In order to avoid such complications, implant placement is recommended to be performed after completion of skeletal growth and maturation.","PeriodicalId":164809,"journal":{"name":"Hellenic Archives of Oral & Maxillofacial Surgery","volume":"42 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120923424","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}
引用次数: 0
Study of the temporomandibular disorders (TMD) with Magnetic resonance imaging (MRI) with active and passive mouth opening 主动和被动张口的颞下颌紊乱(TMD)的磁共振成像研究
Hellenic Archives of Oral & Maxillofacial Surgery Pub Date : 2022-12-01 DOI: 10.54936/haoms2412535
Ch. Papadeli, C. Kouskouras, G. Venetis, Adamantia Filippou
{"title":"Study of the temporomandibular disorders (TMD) with Magnetic resonance imaging (MRI) with active and passive mouth opening","authors":"Ch. Papadeli, C. Kouskouras, G. Venetis, Adamantia Filippou","doi":"10.54936/haoms2412535","DOIUrl":"https://doi.org/10.54936/haoms2412535","url":null,"abstract":"SUMMARY: Objectives: TMD evaluation heavily relies on magnetic resonance imaging (MRI). In several investigations, the MRI examination results do not support the clinical diagnosis. The clinical examination’s diagnostic precision varies, falling between 54 and 90 percent. Our working theory holds that the method used to acquire the MRI is what allows for the acquisition of objective diagnostic findings. Materials and Method: The RDC-TMD diagnostic technique identified 30 patients as having “anterior displacement with reduction as the subjects. The results of the MRI test performed with the mouth closed supported the clinical diagnosis. The distance between the center of the condyle head and the apex of the articular eminence for each joint, as well as the range of motion of the condyle by passive mouth opening (biting a 60ml syringe plunger) and by active maximal mouth opening, without the use of an intraoral appliance, were calculated for each patient in the closed mouth position. Results: The condyle has a wider range of motion with the active opening typically, but the passive opening typically hides subluxation due to hypermobility.Conclusion: Our data underwent statistical analysis, which demonstrated that active and passive opening are two distinct techniques that provide access to various imaging findings.","PeriodicalId":164809,"journal":{"name":"Hellenic Archives of Oral & Maxillofacial Surgery","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122195642","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}
引用次数: 0
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信