1.2.1.docx

Disciplinary module 1. "Local anesthesia in dentistry"
学科模块 1.“牙科中的局部麻醉”

Modular unit 1.2
模块化单元 1.2

"Application and infiltration anesthesia".
“应用和浸润麻醉”。

Lesson 1.2.1. Methods of local anesthesia and their classification. Non-injection methods of anesthesia in dentistry.
第 1.2.1 课.局部麻醉的方法及其分类。牙科麻醉的非注射方法。

Infiltration anesthesia. Kinds. Characteristic"
浸润麻醉。种。特点”

1. Introduction
1. 引言

The problem of pain and anesthesia attracts the attention of doctors of all specialties, since after the first duty - saving a person's life - the most important task was and remains to get rid of pain. Pain is diverse, its shades are described by 102 medical terms. The methods of dealing with pain are just as diverse, which is rather a disadvantage, since it indicates that there is no universal remedy for dealing with pain, just as there is no unified theory of pain. In the clinic, pain is regarded as an unpleasant feeling that causes suffering to the patient of varying intensity - from tolerable to unbearable. The problem of pain and anesthesia exists in the clinic of therapeutic dentistry. Pain is the most frequent, and sometimes the only symptom of most nosological forms in dentistry.
疼痛和麻醉问题引起了所有专业医生的注意，因为在第一项职责 - 挽救一个人的生命 - 最重要的任务是摆脱痛苦。疼痛是多种多样的，它的阴影由 102 个医学术语描述。处理疼痛的方法同样多种多样，这是一个相当不利的因素，因为它表明没有处理疼痛的通用疗法，就像没有统一的疼痛理论一样。在临床上，疼痛被认为是一种不愉快的感觉，它会导致患者遭受不同强度的痛苦 - 从可以忍受到难以忍受。疼痛和麻醉问题存在于治疗性牙科诊所。疼痛是牙科中大多数鼻病形式中最常见，有时也是唯一的症状。

2. The relevance of the topic of the lesson
2. 课程主题的相关性

Pain is a symptom of most acute and chronic human diseases, in addition, it accompanies some dental procedures. For a deep understanding by dentists of the mechanisms and methods of premedication and anesthesia of tissues and organs of the maxillofacial region, a solid knowledge of the functional anatomy and topography of not only the peripheral, but also the central part of the nervous system is necessary.
疼痛是大多数急性和慢性人类疾病的症状，此外，它还伴随着一些牙科手术。为了让牙医深入了解颌面部区域组织和器官的术前用药和麻醉机制和方法，不仅需要了解神经系统外周的功能解剖学和地形，还需要了解神经系统的中枢部分的功能解剖学和地形学。

The purpose of the lesson: To get acquainted with the indications, the methodology for performing various types of infiltration anesthesia.
课程目的：熟悉适应症，进行各种类型浸润麻醉的方法。

Lesson objectives:
课程目标：

1. To study the types of application anesthesia.
1. 研究应用麻醉的类型。

2. To study local anesthetics for terminal anesthesia.
2. 研究终末麻醉的局部麻醉剂。

3. To study the types of infiltration anesthesia.
3. 研究浸润麻醉的类型。

4. Plan for studying the topic
4. 计划学习主题

4.1 Control of the initial level of training of students
4.1 控制学生的初始培训水平

To know: Dental and surgical instruments and equipment.
须知：牙科和手术器械和设备。

To be able to:
为了能够：

• Select and apply a local anesthetic for diseases of the maxillofacial region;
• 为颌面部疾病选择并应用局部麻醉剂;

• Work with dental instruments, materials, tools, and equipment.
• 使用牙科器械、材料、工具和设备。

To own:
要拥有：

• Manual skills in conservative, operative and restorative dentistry.
• 保守、手术和修复牙科的手工技能。

readiness to collect and analyze patient complaints, his medical history, examination results, laboratory, instrumental, patho-anatomical and other studies in order to recognize the condition or establish the presence or absence of a disease
准备好收集和分析患者的投诉、病史、检查结果、实验室、仪器、病理解剖学和其他研究，以识别病情或确定疾病的存在与否

To know:
要知道：

• the classification and main characteristics of medicines, pharmacokinetics and pharmacodynamics, indications and contraindications for the use of medicines;
• 药物的分类和主要特征、药代动力学和药效学、使用药物的适应症和禁忌症;

• modern methods of clinical, laboratory and instrumental diagnostics of therapeutic and surgical patients;
• 治疗和手术患者的临床、实验室和仪器诊断的现代方法;

• types and methods of modern anesthesia;
• 现代麻醉的类型和方法;

• methods of general anesthesia;
• 全身麻醉方法;

• development of possible local complications at the stages of anesthesia, their prevention and methods of elimination;
• 麻醉阶段可能出现的局部并发症、预防和消除方法;

• the role of premedication and sedation in dental interventions in children and adults
• 术前用药和镇静剂在儿童和成人牙科干预中的作用

To be able:
要能够：

• to establish a diagnosis of the disease, based on the principles of evidence and systematic analysis of patient complaints, objective examination data and the results of laboratory and instrumental studies;
• 根据证据原则和对患者投诉的系统分析、客观检查数据以及实验室和仪器研究的结果，确定疾病的诊断;

To own:
拥有：

• methods of integration into practical professional activities of modern methods of conducting a survey, clinical examination; modern methods of planning, analysis and interpretation of laboratory and instrumental studies, morphological analysis of biopsy, surgical and sectional material in therapeutic and surgical practice.
• 将进行调查、临床检查的现代方法整合到实际专业活动中的方法;规划、分析和解释实验室和仪器研究的现代方法，活检的形态学分析，治疗和外科实践中的手术和切片材料。

• carry out the main methods of local anesthesia (application, infiltration, conduction anesthesia) and additional (intraligamentary, intraseptal, intraosseous, intrapulpal anesthesia) on the upper and lower jaws;
• 对上下颌进行局部麻醉（应用、浸润、传导麻醉）和附加（韧带内、间隔内、骨内、牙髓内麻醉）的主要方法;

• choose a means and method of local anesthesia for the prevention of emergency conditions in an outpatient dental appointment in patients at risk;
• 选择一种局部麻醉的手段和方法，以预防高危患者门诊牙科预约中的紧急情况;

the ability to determine the main pathological conditions, symptoms, syndromes of dental diseases, nosological forms in patients in accordance with the International Statistical Classification of Diseases and Related Health Problems, X viewing
根据疾病和相关健康问题国际统计分类确定患者主要病理状况、症状、牙科疾病综合征、病理形式的能力，X 查看

To know:
要知道：

• principles of the International Statistical Classification of Diseases and Related Health Problems, X view
• 疾病和相关健康问题国际统计分类的原则，X 视图

To be able to:
为了能够：

• Use the International Statistical Classification of Diseases and Related Health Problems, X views
• 使用疾病和相关健康问题的国际统计分类，X 视图

To be proficient in:
精通：

• using the International Statistical Classification of Diseases and Related Health Problems, X views
• 使用疾病和相关健康问题的国际统计分类，X 视图

To study this topic, you need the knowledge, skills and abilities gained in the study of the following disciplines (intersubject communications): introduction to the specialty; Russian language and culture of speech; Latin language; physics mathematics; medical informatics; chemistry; biological chemistry-biochemistry of the oral cavity; biology.
要学习这个主题，你需要在学习以下学科（学科间交流）中获得的知识、技能和能力：专业简介;俄罗斯语言和文化;拉丁文;物理数学;医学信息学;化学;生物化学 - 口腔的生物化学;生物学。

Intra-subject communications: psychology, pedagogy; human anatomy - anatomy of the head and neck; histology, embryology, cytology-histology of the oral cavity; normal physiology - physiology of the maxillofacial region.
学科内交流：心理学、教育学;人体解剖学 - 头部和颈部的解剖学;组织学、胚胎学、细胞学 - 口腔的组织学;正常生理学 -颌面区域的生理学。

4.2. Theoretical block
4.2. 理论块

Basic concepts and provisions
基本概念和规定

Non-injection methods of local anesthesia are methods that are not accompanied by tissue damage for the introduction of an anesthetic.
局部麻醉的非注射方法是不伴有组织损伤以引入麻醉剂的方法。

For non-injection local anesthesia, physical (cooling, pressure), chemical (anesthetics), physico-chemical (electro-, ultraphono-, magnetophoresis) methods are used.
对于非注射局部麻醉，使用物理（冷却、压力）、化学（麻醉剂）、物理化学（电、超声、磁电泳）方法。

Application anesthesia is based on the penetration of anesthetic into tissues through intact skin or mucous membrane to a depth of 2-5 mm and blockade of receptors and peripheral nerve fibers. The anesthesia technique consists in applying a solution, gel, film, ointment or aerosol containing an anesthetic to the anesthetized surface. Given the significant toxicity of application anesthetics, the exposure time of each of them must strictly comply with the instructions for their use. It is preferable to use such application methods that will not cause an overdose (film, small cotton ball). Water-soluble drugs (pyromecaine, dicaine) are absorbed faster than others, which increases the likelihood of an overdose. Fat-soluble drugs are absorbed more slowly.
应用麻醉的基础是麻醉剂通过完整的皮肤或粘膜渗透到组织中，深度为 2-5 毫米，并阻断受体和周围神经纤维。麻醉技术包括将含有麻醉剂的溶液、凝胶、薄膜、软膏或气雾剂涂抹在麻醉表面。鉴于应用麻醉剂的显着毒性，每种麻醉剂的暴露时间必须严格遵守其使用说明。最好使用不会导致过量的应用方法（薄膜、小棉球）。水溶性药物（吡咯卡因、二卡因）比其他药物吸收得更快，这增加了过量的可能性。脂溶性药物的吸收速度较慢。

An indication for the use of application anesthesia is the anesthesia of a needle injection, removal of milk or highly mobile permanent teeth, opening of submucosal, periodontal abscesses, oral mucosa, etc.
使用应用麻醉的适应症是针头注射的麻醉、去除牛奶或高度移动的恒牙、打开粘膜下、牙周脓肿、口腔粘膜等。

Contraindications to the use of the method: allergy to local anesthetics, severe liver and kidney disease, hypotension, myasthenia gravis, pathological processes in the skin or mucous membrane in the area of planned anesthesia.
使用该方法的禁忌症：对局部麻醉剂过敏，严重的肝肾疾病，低血压，重症肌无力，计划麻醉区域皮肤或粘膜的病理过程。

Physico-chemical methods of local anesthesia consist in the introduction of an anesthetic into tissues by means of electro-, ultraphono-, magnetophoresis.
局部麻醉的物理化学方法包括通过电、超音、磁电泳将麻醉剂引入组织。

During electrophoresis, gauze moistened with an anesthetic is applied to the anesthetized surface. A hydrophilic pad is placed on top of it, and then an anode electrode. The cathode is placed in the interscapular region or on the forearm. The current strength is selected according to subjective feelings, within 15-20 mA. Duration of exposure - 30 minutes. The indication for the application of the method is the elimination of pain in the maxillofacial region.
在电泳过程中，将用麻醉剂润湿的纱布涂在麻醉表面。在其顶部放置一个亲水垫，然后放置一个阳极电极。阴极放置在肩胛间区域或前臂上。电流强度根据主观感觉选择，在 15-20 mA 之间。暴露时间 - 30 分钟。该方法应用的适应症是消除颌面部区域的疼痛。

Other physical and chemical methods are based on the use of ultrasound and magnetic field as a conductor of anesthetic ions in tissue.
其他物理和化学方法基于使用超声波和磁场作为组织中麻醉离子的导体。

Injection methods of anesthesia are methods that are accompanied by damage to the skin or mucous membrane with a needle or high-pressure anesthetic jet. Injection methods of anesthesia involve the introduction of an anesthetic into the tissues using a syringe and needle or a needleless injector.
麻醉注射方法是用针头或高压麻醉射流对皮肤或粘膜造成损伤的方法。麻醉的注射方法包括使用注射器和针头或无针注射器将麻醉剂引入组织。

There are basic (infiltration, conduction) and additional (intraligamentary, intraseptal, subperiosteal, intrapulpal) injection methods of anesthesia. Infiltration anesthesia consists in impregnation of the tissues subject to painful manipulations with an anesthetic. The anesthetic diffusing from the created depot into the surrounding tissues blocks the nerve plexuses, fibers and receptors of the surgical field.
有基本的（浸润、传导）和额外的（韧带内、间隔内、骨膜下、牙髓内）麻醉注射方法。浸润麻醉包括用麻醉剂对受痛苦作的组织进行浸渍。麻醉剂从形成的仓库扩散到周围组织中，阻断了手术区域的神经丛、纤维和受体。

Direct infiltration anesthesia is based on the impregnation of the tissues of the immediate surgical field with an anesthetic and is used in operations on the soft tissues of the face, neck and oral cavity. By conducting such anesthesia, tissues infiltrate in layers: skin or mucous membrane, subcutaneous tissue or submucosal layer, fascial layers and muscles, before or during the operation. For this, a low concentration anesthetic is used - 0.25 - 0.5 - 1%, which allows you to administer a larger volume of the drug during the operation.
直接浸润麻醉是基于用麻醉剂浸渍直接手术区域的组织，用于面部、颈部和口腔软组织的手术。通过进行这种麻醉，组织在手术前或手术期间分层渗透：皮肤或粘膜、皮下组织或粘膜下层、筋膜层和肌肉。为此，使用低浓度麻醉剂 - 0.25 - 0.5 - 1%，这使您可以在手术过程中施用更大体积的药物。

Method of direct layer-by-layer infiltration anesthesia
直接逐层浸润麻醉方法

Proposed by A. V. Vishnevsky. After antiseptic treatment of the skin, a thin needle is injected into the skin, placing the needle with a bevel to the skin, at an acute angle. The solution is injected slowly, advancing the needle at the same depth and creating a nodule resembling a lemon peel throughout the proposed incision. Then
由 A. V. Vishnevsky 提出。对皮肤进行消毒处理后，将一根细针注射到皮肤中，将针头以锐角斜向皮肤放置。溶液缓慢注入，将针头推进相同的深度，并在整个建议的切口中形成一个类似于柠檬皮的结节。然后the needle is returned to the injection site without pulling it out of the skin, and immersed in the subcutaneous tissue, infiltrating it in the same way. If it is necessary to anesthetize deeper-lying formations, the needle is changed to a thicker one. After tissue infiltration in the incision area, an anesthetic is injected along the sides of an imaginary rhombus, the diagonal of which is the incision line, to anesthetize all tissues of the surgical field. Tight tissue infiltration ensures not only the development of anesthesia, but also their hydropreparation, which facilitates the work of the surgeon. If it is necessary to anesthetize the deeper tissues, the needle is injected under the fasciae, which create fascial cases for the muscles or neurovascular bundles, impregnating them with an anesthetic. When conducting direct infiltration anesthesia in the oral cavity, the same procedure is followed. First, intramucosal, then submucosal anesthesia is performed.
针头返回注射部位而不将其从皮肤中拉出，并浸入皮下组织，以相同的方式浸润。如果需要麻醉较深的地层，则更换为较粗的针头。在切口区域组织浸润后，沿着假想菱形的侧面注射麻醉剂，其对角线是切口线，以麻醉手术区域的所有组织。紧密的组织浸润不仅确保了麻醉的发展，还确保了它们的加氢，这有利于外科医生的工作。如果需要麻醉更深的组织，将针头注射到筋膜下方，为肌肉或神经血管束创建筋膜外壳，用麻醉剂浸渍它们。在口腔进行直接浸润麻醉时，遵循相同的程序。首先进行粘膜内麻醉，然后进行粘膜下麻醉。

Indirect infiltration anesthesia is used to block the dental plexus in the alveolar process of the upper jaw and the frontal area of the lower jaw. In this case, anesthetics of a higher concentration are used than for direct anesthesia. Anesthesia occurs as a result of the diffusion of the drug from the submucosal layer into the thickness of the cancellous bone, where the alveolar plexus lies.
间接浸润麻醉用于阻断上颌和下颌额部牙槽突中的牙丛。在这种情况下，使用浓度高于直接麻醉的麻醉剂。麻醉是由于药物从粘膜下层扩散到牙槽丛所在的松质骨的厚度而发生的。

The effectiveness of indirect anesthesia depends on the diffusion capacity of the anesthetic, its volume (to a lesser extent), concentration (to a greater extent), the thickness and density of the cortical plate. In those areas of the alveolar process where there is a thick cortical plate (the external oblique line of the lower jaw in the region of the lower molars and the zygomatic-alveolar ridge in the upper jaw in the region of the first molars), infiltration anesthesia alone is usually not effective enough. Therefore, during manipulations in these areas, conduction anesthesia is used.
间接麻醉的有效性取决于麻醉剂的扩散能力、体积（较小）、浓度（较大）、皮质板的厚度和密度。在牙槽突有厚皮质板的区域（下颌外斜线在下磨牙区域和颧骨-牙槽嵴在第一磨牙区域），单独的浸润麻醉通常不够有效。因此，在这些区域进行作时，使用传导麻醉。

When conducting indirect infiltration anesthesia, the mucogingival line (transitional fold) is used as a guide for needle injection, which is clearly visible throughout the alveolar process of the upper jaw from the vestibular side and on both sides on the alveolar part of the lower jaw. The transitional fold is the place where the attached gingiva passes into the unattached gingiva, which has a submucosal layer, and it is located parallel to the gingival margin. The needle during indirect infiltration anesthesia can be placed horizontally, parallel to the dentition or vertically along the axis of the tooth. A needle with a length of 16-25 mm and a diameter of 0.3-0.4 mm is usually used. The cut of the needle should be directed towards the bone. With a horizontal needle position, the injection is performed, stepping back 0.5-1.0 cm from the transitional fold and medially to the tooth being removed, so that the end of the needle stops in the projection of the
在进行间接浸润麻醉时，粘膜龈线（过渡皱襞）用作针头注射的导向，从前庭侧和下颌牙槽部分的两侧，在上颌的整个牙槽过程中清晰可见。过渡皱襞是附着的牙龈进入未附着的牙龈的地方，该牙龈具有粘膜下层，并且与牙龈边缘平行。间接浸润麻醉期间的针头可以水平放置，平行于牙列或沿牙齿轴线垂直放置。通常使用长度为 16-25 毫米、直径为 0.3-0.4 毫米的针头。针头的切口应朝向骨骼。以水平针头位置进行注射，从过渡皱襞向后退 0.5-1.0 厘米，向内侧到被移除的牙齿，使针头的末端停止在root apex, where the anesthetic depot is created in the submucosal layer. With the vertical direction of the needle, the injection is performed on the axis of the tooth, retreating 0.5 cm from the transitional fold, introducing an anesthetic, then advance the end of the needle to the level of the apex of the tooth, where a depot is created. While advancing the needle, care should be taken to ensure that it does not fall under the periosteum or go into the soft tissues. You can determine the projection of the root apex by mentally setting aside two heights of the crown of the tooth on the projection of its root.
根尖，在粘膜下层中创建麻醉药库。随着针头的垂直方向，在牙齿的轴线上进行注射，从过渡褶皱后退 0.5 厘米，引入麻醉剂，然后将针头的末端推进到牙齿顶点的水平，在那里形成一个仓库。在推进针头时，应注意确保它不会落入骨膜下或进入软组织。您可以通过在脑海中将牙冠的两个高度放在牙根的突出部分来确定牙根尖的突出。

Infiltration anesthesia on the upper and lower jaw 上下颌浸润麻醉
Name 名字	Methodology 方法论	Зона обезболивания	Время насту-пления
Infiltration anesthesia 浸润麻醉	The needle is immersed in soft tissues horizontally at an angle of 45 to the alveolar process. The bevel of the needle is facing the bone. From the vestibular side, the needle is injected into the transitional fold. From the palatal side, the needle is injected into the angle formed by the alveolar and palatine processes of the upper jaw, no more than 0.5 ml of anesthetic is injected. From the lingual side of the alveolar part of the lower jaw, the anesthetic is injected into the place of transition of the mucous membrane of the alveolar part to the sublingual region. 针头以与肺泡突成 45° 的角度水平浸入软组织中。针头的斜面朝向骨头。从前庭侧，将针头注射到过渡皱襞中。从腭侧，将针头注射到上颌的肺泡和腭突形成的角度，注射不超过 0.5 毫升的麻醉剂。从下颌牙槽部分的舌侧，将麻醉剂注射到牙槽部分粘膜到舌下区域的过渡位置。	Gingiva, alveolar process and tooth, in the area of which anesthesia is performed. 牙龈、牙槽突和牙齿，在进行麻醉的区域。	7-10 minutes 7 10 分钟

4.4. Final control
4.4. 最终控制

Test questions:
测试题：

1. Types of application anesthesia.
1. 应用麻醉的类型。

2. Local anesthetics for terminal anesthesia.
2. 终末麻醉的局部麻醉剂。

3. Types of infiltration anesthesia.
3. 浸润麻醉的类型。

Test tasks:
测试任务：

1. CHOOSE THE MOST ACCURATE DESCRIPTION OF THE ALGORITHM FOR INFILTRATION ANESTHESIA IN THE AREA OF THE TOOTH 1.4
1. 选择最准确的描述牙区浸润麻醉的算法 1.4

a) the direction of the needle at an angle of 45 to the surface of the mucosa, just below the projection of the root apex;
a）针头与粘膜表面成 45 角的方向，刚好在根尖的投影下方;

b) the direction of the needle at an angle of 45 to the surface of the mucosa, slightly above and medially to the projection of the root apex;
b）针的方向与粘膜表面成 45 度角，略高于根尖的突起和内侧;

c) the direction of the needle at an angle of 90 to the surface of the mucosa, the bevel of the needle is distal to the axis of the tooth.
c）针的方向与粘膜表面成 90 度角，针的斜面远离齿轴。

2. RECOMMENDED NEEDLE DEPTH FOR INJECTION ANESTHESIA
2. 注射麻醉的推荐针头深度

a) to the ground
a）到地面

b) up to 1⁄2 needle length
b）最大 1⁄2 针长

c) up to 1/3 of the needle length
c）最大 1/3 针长

3. TO AVOID PAIN REACTION DURING INJECTION, IT IS NECESSARY:
3. 为避免注射过程中出现疼痛反应，有必要：

a) use application anesthesia at the injection site of the needle
a）在针头的注射部位使用应用麻醉

b) slowly insert the needle
b）慢慢插入针头

c) quickly inject the anesthetic
c）快速注射麻醉剂

d) treat the injection site with alcohol
d）用酒精处理注射部位

4. INDICATE THE GROUP OF TEETH FOR THE TREATMENT OF WHICH INFILTRATION ANESTHESIA IS USUALLY INSUFFICIENT
4. 指出浸润麻醉通常不足的治疗牙齿组

a) incisors and canines of the upper jaw
a）上颌的门牙和尖牙

b) incisors and canines of the lower jaw
b）下颌的门牙和尖牙

c) molars of the upper jaws
c）上颌磨牙

d) molars of the lower jaw
d）下颌磨牙

5. INDICATE THE FORMULA OF A TOOTH FOR THE TREATMENT OF WHICH INFILTRATION ANESTHESIA WITH A LOCAL ANESTHETIC SOLUTION ON THE BASIS OF ARTICAINE IS NOT ENOUGH
5. 说明治疗用基于 ARTICAINE 的局部麻醉液浸润麻醉是不够的牙齿的配方

a) tooth 33
a）齿 33

b) tooth 46
b）齿 46

c) tooth 25
c）齿 25

d) tooth 14
d）齿 14

4.5. Homework
4.5. 家庭作业

1. Theoretical training: “Periodontal methods of local anesthesia (intraligamentary, intraseptal, intraosseous, intrapulpal). Indications and contraindications for their use.
1. 理论培训：“局部麻醉的牙周法（韧带内、间隔内、骨内、牙髓内）。使用它们的适应症和禁忌症。

Literature recommended for self-training of students:
推荐用于学生自我培训的文献：

Basic Literature
基础文献

1. Local anesthesia in dentistry: a textbook for students studying in the specialty "Dentistry" / ed. E. A. Bazikyan. - Moscow: GEOTAR-Media, 2012. - 144 p. http://www.studmedlib.ru/book/ISBN9785970430958.html
1. 牙科中的局部麻醉：学习“牙科”专业的学生的教科书 / E. A. Bazikyan 编辑。- 莫斯科：GEOTAR-Media，2012 年。- 144 页 http://www.studmedlib.ru/book/ISBN9785970430958.html

2. Features of conduction anesthesia during tooth extraction operations in outpatient dentistry [Text] / ed. A. V. Sevbitova. - Moscow: GEOTAR-Media, 2017. - 168 p. : ill. http://www.studmedlib.ru/book/ISBN9785970438121.html.
2. 门诊牙科拔牙手术中传导麻醉的特点 [文本] / A. V. Sevbitova 编辑。- 莫斯科：GEOTAR-Media，2017 年。- 168 页：生病http://www.studmedlib.ru/book/ISBN9785970438121.html。