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DR. MD. ARIFUR RAHMANBDS (D.U), MPH
ASSISTANT PROFESSOR & DENTAL UNIT HEAD NORTH EAST MEDICAL COLLEGE DENTAL UNIT
SYLHET, BANGLADESH
INTRODUCTION TO DENTAL MATERIALS
Science Of Dental Materials
Is defined as,“The Study of composition and properties of dental materials and the manner in which they interact with the environment they are placed”.
Science Of Dental Materials
Science of dental materials is a basic science which deals with physical,
mechanical and biological properties of dental materials. The study of Science of
dental materials gives the operator a basic knowledge about the materials. This help to choose a material and allow him/her to
effectively manipulate it.
The Science of Dental Materials:
“Why are we studying this field?”1. for the knowledge to make optimal selection of
materials2. To understand the behavior of the materials, use,
handling, manipulation3. Safety considerations of the materials4. Patient education regarding dental restoratives5. Recognition of materials – proper care of
prostho/restorations 6. Understand the professional literature
History of Dental Materials:Dating as early as 500 B.C. - present
Metals – goldPlaster and wax modelsProsthetics of bone, ivory, wax, metalsPorcelains – late 1700’sAmalgam – early 1800’sAcrylics – 1940’sAdhesive dentistry – 1970’s - present
Oral Environment Very demanding. There can be
1. Temperature variations.2. pH Variations.3. Variations in Masticatory forces.
Temperature Variations
Normal temperature of oral cavity (32℃ to 37℃).
On intake of a cold/hot food or drink temperature range increases (0℃ to 70℃).
pH Variations
pH of saliva is neutral (7.0)On intake of acidic fruit juices or
alkaline medicaments, pH may vary from 2.0 to 11.0 .
Variations in Masticatory Forces Muscles of
Mastication apply forces to the dentition.
Masticatory forces vary from tooth to tooth.
Average force applied by the tooth increases from anterior to posteriors.
Tooth Average force (N)
Second molar
800
First molar 390
Bicuspids 288
Cuspids 208
Incisors [email protected]
Characteristics of Ideal Materials: It should be
Biocompatible – Non-toxic, non-irritating, non-allergenic
Mechanically stable & durable –Strong, resistant to fracture
Resistant to Corrosion –Does not deteriorate over time
Dimensionally Stable –Little change by temperature & solvents
Characteristics of Ideal Materials (cont.):
Minimal conduction –Insulates against thermal/electrical change
Esthetic –Looks like oral tissue
Easy to manipulate –Minimal/reasonable effort & time needed
Adheres to tissues –Retains onto, and seals, tooth structure
Characteristics of Ideal Materials:
Tasteless and Odorless –Not unpleasant to patient
Cleanable/Repairable –Easily maintained or fixed
Cost-effective –Affordability vs. benefits/disadvantages
Classification of Dental materials
All dental materials fall under 4 main groups:1. Polymers.2. Metals.3. Ceramics.4. Composites.
POLYMERSChemical compound consisting of large
organic molecules formed by the union of many smaller monomer units is called a “POLYMER”
Chemical reaction in which low molecular weight monomers are converted into high molecular weight polymer chains “POLYMERIZATION”
METALS
“An opaque lustrous chemical substance that is a good conductor of heat and electricity, and when polished is a good reflector of light”.
The Metals Handbook (1992)
CERAMICS“An inorganic compound with non
metallic properties, typically composed of metallic (or semi-metallic) and non metallic elements.”
COMPOSITESComposite materials (also called
composition materials or shortened to composites) are materials made from two or more constituent materials with significantly different physical or chemical properties, that when combined, produce a material with characteristics different from the individual components.
CLASSIFICATION OF DENTAL MATERIALS
Dental materials can be classified as:1. Preventive dental materials.2. Restorative dental materials.
a) Direct restorative dental materials.b) Indirect restorative dental materials.
3. Auxiliary dental materials.
1. PREVENTIVE DENTAL MATERIALS
Basic aim is to provide resistance to the progression of an active carious lesion.
Carious lesion cause the demineralization of the dental enamel.
These include:a) Chemotherapeutic agents like Dentifrices, Mouthwashes and cavity varnishes.b) Pit and fissure sealants.c) Floride releasing cements.
1. PREVENTIVE DENTAL MATERIALS (Cont.)
Preventive dental materials can also serve as Restorative materials.
Can be either,1) Short time periods.2) Moderately long time period.3) Longest time periods.
2. RESTORATIVE DENTAL MATERIALS (Cont.)
Help to repair or replace defected tooth structure.These include:1. Amalgam.2. Bonding agents.3. Resin based composites.4. Compomers.5. Ceramics.6. Liners.7. Cement bases.8. Dental polymers.
Types of Restorative dental materials
a) Direct restorative materials: Used intraorally. fabricate restorations / prosthetic devices
directly on the teeth or tissues.a) Indirect restorative materials: Used extra orally. Formed indirectly over a cast or models.
3. AUXILIARY DENTAL MATERIALS
Materials used in the process of fabricating dental prosthesis. These include:
1. Impression materials.2. Dental waxes.3. Gypsum casts and model materials.4. Finishing and polishing abrasives.5. Acrylic resins for impressions.6. Acid etching solutions.
4. TEMPORARY RESTORATIVE DENTAL MATERIALS
Sub category of restorative materials. Intended to be used to restore the tooth temporarily. These include:
1. Orthodontic wires. 2. Cements used as temporary liners.3. Cements used as temporary filling materials.4. Acrylic resins used for inlays, inlays, crowns
and fixed partial dentures.
SELECTION OF DENTAL MATERIALS
1. Analysis of the problem.2. Consideration of the
requirements.3. Consideration of the available
materials and their properties.4. Choice of a suitable material.
1. Analysis of the problem
Basic and very important step.Incorrect analysis may lead to wrong
treatment plan.Poor prognosis and failure of
treatment.e.g. Selection of a filling material.
2. Consideration of the requirements
Enlist the requirements that a material must meet.
Requirements of a material are dependent upon the situation.
3. Consideration of the available materials and their properties
Clear concept about the properties. In case of immediate problem,
Must choose from the materials in hand.Dentist must be up to date with the
advancements.Thorough comparison of Properties of the
available materials with requirements.
4. Choice of a suitable material
Final step. Narrowing the range of choice.
Factors:1. Availability.2. Ease of handling.3. Cost effectiveness.
Identification of Restorations:“Dental Restoration” –
Restores function & appearance of oral structure lost by pathology, injury, or is congenitally missing
Examples:Pathology – caries: fillingInjury – broken tooth: crownCongenitally Missing: prosthetic (i.e. bridge)
Identification of Restorations:
Direct Restoration –A restoration that is created and placed
directly into the prep site of the tooth(i.e. amalgam filling, composite filling)
Indirect Restoration – A restoration that is created outside of the
mouth on a model of the prepped tooth and later fixed into the mouth
(i.e. gold crown, denture)
Direct Fillings:
Usually made of amalgam (“silver” metal) or composite (acrylic) materials
For caries of various degrees; anterior or posterior teeth
Posterior amalgam fillings
Crown: Indirect restoration
to replace missing crown of tooth, or protect remaining crown of tooth
Caries, fractures, teeth with RCT, esthetics
Made of porcelain, metals, or both
Porcelain-Fused-to-Metal (PFM) Crown
Bridge:
An indirect restoration; to replace one or more missing teeth
“fixed” – not removable; cemented to existing teeth
Made of porcelain, metals, or bothAbutment – the existing tooth/teeth
supporting the bridgePontic – the replacement tooth
Bridge:
Anterior bridge on model
Anterior bridge before cementation
How many abutment teeth
does the patient have?
Indirect Restorations:
Inlay –A fabricated restoration made of metal or
porcelain that replaces missing tooth structure; does NOT include the restoration of any cusps
Onlay – A fabricated restoration (as above) that
DOES include the restoration of at least one cusp
Veneers:
All-porcelain or acrylic facing for tooth
Primarily used for esthetic reasons
Can alter shape & color of existing tooth
Denture:
The removable dental prosthetic used to replace all of the teeth in an arch; patient is edentulous.Made of acrylic (teeth may be porcelain)
“Partial Denture” – replaces some teeth in the arch; patient is partially edentulous.Made of acrylic usually with metal
substructure and [email protected]
Endodontic Restorations:
“Endodontic” – “inside” the tooth; root canal treatment (RCT)Gutta percha – used to fill the canalPost and Core –
The post is a metal piece that is screwed into and cemented into the root canal
The core is built-up around the post to create more available tooth structure
Endodontic Restorations:
Gutta Percha
Post
(Silver Points used to be used in the canal as a filler.)
(The core is built upon this post.)
Pediatric Restorations:
Space Maintainer: Holds space where
primary tooth was prematurely lost
Stainless steel band/crown with loop
Fabricated outside of the mouth; cemented
