BYBY

HEAD OF DEPARTMENT HEAD OF DEPARTMENT DR RASHID HASSAN DR RASHID HASSAN

ASSISTANT PROFESSOR ASSISTANT PROFESSOR SCIENCE OF DENTAL MATERIALS SCIENCE OF DENTAL MATERIALS

DEPARTMENTDEPARTMENTRAWAL INSTITUTE OF HEALTH RAWAL INSTITUTE OF HEALTH

SCIENCESSCIENCESRAWAL COLLEGE OF DENTISTRYRAWAL COLLEGE OF DENTISTRY

ISLAMABADISLAMABAD

LECTURE 1LECTURE 1

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INTRODUCTION TO INTRODUCTION TO DENTAL MATERIALS AND DENTAL MATERIALS AND

INSTRUMENTSINSTRUMENTS

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Science Of Dental MaterialsScience Of Dental Materials

Is defined as,Is defined as,

““The Study ofThe Study of compositioncomposition and and propertiesproperties of dental materials and of dental materials and the the manner in which they interact manner in which they interact with the environmentwith the environment in which in which they are placed”.they are placed”.

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Oral EnvironmentOral Environment

Very demanding.Very demanding.

There can beThere can be

1.1. Temperature variations.Temperature variations.

2.2. pH Variations.pH Variations.

3.3. Variations in Masticatory forces.Variations in Masticatory forces.44

Temperature VariationsTemperature Variations

Normal temperature of oral cavity (32Normal temperature of oral cavity (32℃ to ℃ to 37℃).37℃).

On intake of a cold/hot food or drink On intake of a cold/hot food or drink temperature range increases (0temperature range increases (0℃ to ℃ to 70℃).70℃).

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pH VariationspH Variations

pH of saliva is neutral (7.0)pH of saliva is neutral (7.0)

On intake of acidic fruit juices or On intake of acidic fruit juices or alkaline medicaments, pH may alkaline medicaments, pH may vary from 2.0 to 11.0 .vary from 2.0 to 11.0 .

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Variations in Masticatory ForcesVariations in Masticatory Forces

Muscles of Muscles of Mastication apply Mastication apply forces to the dentition.forces to the dentition.

Masticatory forces Masticatory forces vary from tooth to vary from tooth to tooth.tooth.

Average force applied Average force applied by the tooth increases by the tooth increases from anteriors to from anteriors to posteriors.posteriors.

ToothTooth AverageAverage

force (N)force (N)

Second Second molarmolar

800800

First molarFirst molar 390390

BicuspidsBicuspids 288288

CuspidsCuspids 208208

IncisorsIncisors 15515577

IDEAL PROPERTIES OF A IDEAL PROPERTIES OF A DENTAL MATERIALDENTAL MATERIAL

Biocompatible.Biocompatible.Binds permanently with the tooth structure.Binds permanently with the tooth structure.Esthetically acceptable.Esthetically acceptable.Exhibit properties similar to the tooth Exhibit properties similar to the tooth

structure.structure. Initiate tissue repair and regeneration.Initiate tissue repair and regeneration.

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DENTAL MATERIALSDENTAL MATERIALS

Ultimate goal:Ultimate goal:

Improve and maintain the quality of life of a Improve and maintain the quality of life of a dental patient.dental patient.

All dental materials fall under 4 main groups:All dental materials fall under 4 main groups:

1.1. Polymers.Polymers.

2.2. Metals.Metals.

3.3. Ceramics.Ceramics.

4.4. Composites.Composites.

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POLYMERSPOLYMERS

Chemical compound consisting of Chemical compound consisting of large organic molecules formed by large organic molecules formed by the union of many smaller monomer the union of many smaller monomer units is called a “POLYMER”units is called a “POLYMER”

Chemical reaction in which low Chemical reaction in which low molecular weight monomers are molecular weight monomers are converted into high molecular weight converted into high molecular weight polymer chains “POLYMERIZATION”polymer chains “POLYMERIZATION”

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METALSMETALS

““An opaque lustrous chemical An opaque lustrous chemical substance that is a good conductor of substance that is a good conductor of heat and electricity, and when heat and electricity, and when polished is a good reflector of light”.polished is a good reflector of light”.

The Metals Handbook (1992)The Metals Handbook (1992)

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CERAMICSCERAMICS

““An inorganic compound with non An inorganic compound with non metallic properties, typically metallic properties, typically composed of metallic (or semi-composed of metallic (or semi-metallic) and non metallic elements.”metallic) and non metallic elements.”

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COMPOSITESCOMPOSITES

““A material formed from two distinct A material formed from two distinct phases is called a composite phases is called a composite material”material”

Two distinct phases can be easily Two distinct phases can be easily separated on microscopic scale.separated on microscopic scale.

Final properties are either superior or Final properties are either superior or intermediate to the individual intermediate to the individual constituents.constituents.

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CLASSIFICATION CLASSIFICATION OF OF

DENTAL MATERIALSDENTAL MATERIALS

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CLASSIFICATION OF DENTAL CLASSIFICATION OF DENTAL MATERIALSMATERIALS

Dental materials can be classified as:Dental materials can be classified as:

1.1. Preventive dental materials.Preventive dental materials.

2.2. Restorative dental materials.Restorative dental materials.a)a) Direct restorative dental materials.Direct restorative dental materials.

b)b) Indirect restorative dental materials.Indirect restorative dental materials.

3.3. Auxiliary dental materials.Auxiliary dental materials.

4.4. Temporary restorative dental materials.Temporary restorative dental materials.

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1.1. PREVENTIVE DENTAL PREVENTIVE DENTAL MATERIALSMATERIALS

Basic aim is to provide resistance to the Basic aim is to provide resistance to the progression of an active carious lesion.progression of an active carious lesion.

Carious lesion cause the demineralization of Carious lesion cause the demineralization of the dental enamel.the dental enamel.

These include:These include:a) Chemotherapeutic agents like Dentifrices, a) Chemotherapeutic agents like Dentifrices, Mouthwashes and cavity varnishes.Mouthwashes and cavity varnishes.b) Pit and fissure sealants.b) Pit and fissure sealants.c) Floride releasing cements.c) Floride releasing cements.

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1.1. PREVENTIVE DENTAL PREVENTIVE DENTAL MATERIALSMATERIALS

Preventive dental materials can also serve Preventive dental materials can also serve as Restorative materials.as Restorative materials.

Can be either,Can be either,

1) Short time periods.1) Short time periods.

2) Moderately long time period.2) Moderately long time period.

3) Longest time periods.3) Longest time periods.

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2.2. RESTORATIVE DENTAL RESTORATIVE DENTAL MATERIALSMATERIALS

Help to repair or replace defected tooth structure.Help to repair or replace defected tooth structure. These include:These include:1.1. Amalgam.Amalgam.2.2. Bonding agents.Bonding agents.3.3. Resin based composites.Resin based composites.4.4. Compomers.Compomers.5.5. Ceramics.Ceramics.6.6. Liners.Liners.7.7. Cement bases.Cement bases.8.8. Dental polymers.Dental polymers.

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Types of Restorative dental Types of Restorative dental materialsmaterials

a)a) Direct restorative materials:Direct restorative materials: Used intraorally.Used intraorally. fabricate restorations / prosthetic devices fabricate restorations / prosthetic devices

directly on the teeth or tissues.directly on the teeth or tissues.

a)a) Indirect restorative materials:Indirect restorative materials: Used extraorally.Used extraorally. Formed indirectly over a cast or models.Formed indirectly over a cast or models.

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3.3. AUXILIARY DENTAL AUXILIARY DENTAL MATERIALSMATERIALS

Materials used in the process of fabricating Materials used in the process of fabricating dental prosthesis.dental prosthesis.

These include:These include:1.1. Impression materials.Impression materials.2.2. Dental waxes.Dental waxes.3.3. Gypsum casts and model materials.Gypsum casts and model materials.4.4. Finishing and polishing abrasives.Finishing and polishing abrasives.5.5. Acrylic resins for impressions.Acrylic resins for impressions.6.6. Acid etching solutions.Acid etching solutions.

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4. 4. TETEMPORARY RESTORATIVE MPORARY RESTORATIVE DENTAL MATERIALSDENTAL MATERIALS

Sub category of restorative materials.Sub category of restorative materials. Intended to be used to restore the tooth Intended to be used to restore the tooth

temporarily.temporarily. These include:These include:1.1. Orthodontic wires. Orthodontic wires. 2.2. Cements used as temporary liners.Cements used as temporary liners.3.3. Cements used as temporary filling materials.Cements used as temporary filling materials.4.4. Acrylic resins used for inlays, onlays, crowns Acrylic resins used for inlays, onlays, crowns

and fixed partial dentures.and fixed partial dentures.

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SELECTION SELECTION OF OF

DENTAL MATERIALSDENTAL MATERIALS

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SELECTION OF DENTAL SELECTION OF DENTAL MATERIALSMATERIALS

1.1. Analysis of the problem.Analysis of the problem.

2.2. Consideration of the Consideration of the requirements.requirements.

3.3. Consideration of the available Consideration of the available materials and their properties.materials and their properties.

4.4. Choice of a suitable material.Choice of a suitable material.

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1.1. Analysis of the problemAnalysis of the problem

Basic and very important step.Basic and very important step.Incorrect analysis may lead to wrong Incorrect analysis may lead to wrong

treatment plan.treatment plan.Poor prognosis and failure of Poor prognosis and failure of

treatment.treatment.

e.g. Selection of a filling material.e.g. Selection of a filling material.

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2. 2. Consideration of the Consideration of the requirementsrequirements

Enlist the requirements that a Enlist the requirements that a material must meet.material must meet.

Requirements of a material are Requirements of a material are dependent upon the situation.dependent upon the situation.

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3.3. Consideration of the available Consideration of the available materials and their propertiesmaterials and their properties

Clear concept about the properties.Clear concept about the properties. In case of immediate problem,In case of immediate problem,

Must choose from the materials in hand.Must choose from the materials in hand.Dentist must be up to date with the Dentist must be up to date with the

advancements.advancements.

Thorough comparison of Properties of the Thorough comparison of Properties of the available materials with requirements.available materials with requirements.

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4. 4. Choice of a suitable Choice of a suitable materialmaterial

Final step.Final step. Narrowing the range of choice.Narrowing the range of choice.

Factors:Factors:

1.1. Availability.Availability.

2.2. Ease of handling.Ease of handling.

3.3. Cost effectiveness.Cost effectiveness.

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QUESTIONS???QUESTIONS???QUESTIONS???QUESTIONS???

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