Clinical Techniques of Dental Prevention

1. Clinical Techniques of Dental Prevention Jiang Han Department of Preventive Dentistry ,School of Stomatology, Wuhan University

2. 教学要求 掌握： 一、窝沟封闭 1.概念; 2.窝沟封闭的临床应用: (1) 适应证和非适应证；(2) 操作方法及步骤 二、预防性树脂充填： 1.定义; 2. 适应证；3. 临床操作步骤 三、ART： 1.基本概念; 2.适应证;3.操作方法

3. 熟悉： 一、窝沟封闭： 1. 窝沟解剖形态及患龋特点 2. 封闭剂组成、类型及特点 了解： 一、窝沟封闭： 1.酸蚀的作用; 2.临床效果评价 二、ART：由来及发展

4. Introduction  Fluorides: Smooth surfaces ( 10%), Occlusal pits and fissures ( 90%) • Occlusal surfaces: The pits and fissures are approximately eight times as vulnerable as the smooth surfaces.

11. Dental Caries • 龋病首先发生在窝沟壁，表现为狭窄处相对的沟壁上牙釉质龋损的形成。 • 龋病形成早期阶段，点隙裂沟底部没受到影响，随着龋病继续发展，沟壁病损逐渐扩大，最后累及沟底，形成金字塔形的损害。

18. Several agents to deal with  1895: Wilson, dental cement  1929: Bodecker, enameloplasty  1923,1936: Hyatt, Prophylactic odontotomy  Do nothing: wait and watch  1960s: pit-and-fissure sealants

19. Concept Pits and fissure sealants are materials which are designed to prevent pit and fissure caries. They are applied mainly to the occlusal surfaces of the teeth in order to obliterate the occlusal fissures, and remove the sheltered environment in which caries may thrive.

20. Concept With this option, a liquid plastic is flowed over the occlusal surface of the tooth where it penetrates the deep fissure to fill areas that cannot be cleaned with the toothbrush. The hardened sealant present a barrier between the tooth and the hostile oral environment.

21. Indication of Sealants  A deep occlusal fissure, fucal or lingual pit is present  An intact occlusal surface is present where the contralateral tooth surface is carious or restored  An incipient lesion exists

22. Indication of Sealants  3-4 years: deciduous molars;  6-7 years: the first permanent molars  11-13 years: the second

23. Contraindication of Sealants  Patients behaviour does not permit use of adequate dry-field techniques throughout the procedure  An open occlusal carious lesion exits  Caries exist on other surfaces of the same tooth  A large occlusal restoration is already present

24. Other consideration in tooth selection  Used in fluoride areas as well as in nonfluoride areas  Placed on the teeth of adults: drug- or radiation-induced xerostomia  The disease susceptibility of the tooth  In handicapped patients

25. Background of Sealants  Polyurethanes ( 氰基丙烯酸脂)  Cyanoacrylates (聚氨基甲酸乙脂)  Bisphenol A –glycidyl methylacrylate (Bis-GMA) (双酚A甲基丙烯酸缩水甘油酯)

26. Accepted by ADA Concise Brand White Sealant (3M Company)  Visio-Seal (ESPS)  Delton  Nuva-Seal  Oralin Pit and Fissure Sealant

27. Composition of sealants  Resin(树脂基质): Gis-GMA  Monomer（单体、稀释剂）: the liquid plastic  Catalyst（引发剂）: benzoyl peroxide

28. Glass Ionomer Sealants  Fluoride release  Cariostatic effect  Poor retention (6-12 months)

29. Fluoride-releasing Sealants  Add fluoride to sealants ( 20 years)  Increase the enamel resistance to caries, antibacterial properties  Reduce the incidence and severity of secondary caries

30. Polymerization of Sealants  Monomer + catalyst ----- Polymer  Light curing: ultraviolet, visible blue light  Self-curing: autopolymerization, cold cure

31. Self-curing Sealants  Do not require light source  The time allowed for sealant manipulation and placement must not be exceeded

32. Light-curing Sealants  Operator can initiate polymerization at any time  Polymerization is shorter than self-curing  Require a light source  Equal in retention

33. Question 1 Which of the following statement, if any, are correct? • In an area with fluoridated water, a lower incidence of caries can be expected, along with a lower proportion of occlusal to smooth surface lesions • Sealants should never be lowed over incipient caries • Sealants are contraindicated for adults

34. Question 2 Which of the following statement, if any, are correct? 1. Bis-GMA are the initials used to specify the chemical family of plastics containing bisphenol A-glycidyl methylacrylate 2. A monomer can polymerize, but a polymer cannot monomerize