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Clinical Techniques of Dental Prevention

Jiang Han Department of Preventive

Dentistry ,School of Stomatology, Wuhan University

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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

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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

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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.

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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。

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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

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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.

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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.

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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

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Indication of Sealants

3-4 years: deciduous molars;

6-7 years: the first permanent molars

11-13 years: the second

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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

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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

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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 )

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Accepted by ADA

Concise Brand White Sealant (3M

Company)

Visio-Seal (ESPS)

Delton

Nuva-Seal

Oralin Pit and Fissure Sealant

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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

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Glass Ionomer Sealants

Fluoride release

Cariostatic effect

Poor retention (6-12 months)

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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

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Polymerization of Sealants

Monomer + catalyst ----- Polymer

Light curing: ultraviolet, visible blue light

Self-curing: autopolymerization, cold cure

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Self-curing Sealants

Do not require light source

The time allowed for sealant manipulation and placement must not be exceeded

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Light-curing Sealants

Operator can initiate polymerization at any time

Polymerization is shorter than self-curing

Require a light source

Equal in retention

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Question 1 Which of the following statement, if any, are

correct?1. 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

2. Sealants should never be lowed over incipient caries

3. Sealants are contraindicated for adults

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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