Dental materials (C)

Copyright 2003, Elsevier Science (USA). All rights reserved.
Chapter 43
Restorative and Esthetic
Dental Materials
Copyright 2003, Elsevier Science (USA).
All rights reserved. No part of this product may be reproduced or transmitted in any
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Produced in the United States of America
ISBN 0-7216-9770-4

Introduction
Restorative dental materials fulfill an important
role in the way dentistry is delivered today.

Standardization of Dental Materials
 ADA: criteria for a new material
• Must not be poisonous or harmful to the body.
• Must not be harmful or irritating to the tissues
of the oral cavity.
• Must help protect the tooth and oral tissues of
the oral cavity.
• Must resemble the natural dentition.
• Must be easily formed and placed in the
mouth.

Properties of Dental Materials
 Mechanical properties must withstand the
biting and chewing force in the posterior area
of the mouth.
 Force is any push or pull on matter.
 Stress is the reaction within the material that
can cause distortion.
 Strain is the change produced within the
material that occurs as the result of stress.

Mechanical Properties
 Types of stress and strain:
• Tensile stress pulls and stretches the
material.
• Compressive stress pushes the material
together.
• Shear stress is the breakdown of the
material.

Thermal Changes
 A change in temperature in the oral cavity due
to either a hot or cold product.
 Contraction and expansion
• Dental materials will contract or expand at
their own rate.
• Change in temperature can cause a dental
material to pull away from the tooth.
• Microleakage
• Faulty restoration

Electrical Properties
 An electrical current, or galvanic action, is
created when two different or dissimilar metals
are present in the oral cavity.
 Conditions:
• Saliva.
• Two metallic components of different
composition.
• Electrical current.
• Galvanic action, or shock, is the coming
together of all conditions.

Corrosive Properties
 Reaction a metal has when it comes into
contact with corrosive products.
 Solubility is the degree to which a substance
will dissolve in a given amount of another
substance.

Application Properties
 Flow:
• The dental material must be pliable enough
to be placed in the preparation.
 Adhesion:
• The force that causes unlike materials to
adhere to each other.
 Wetting is the ability of a liquid to flow over
the surface.
 Viscosity is the property of a liquid that causes
it not to flow easily.

Application Properties- cont’d
 Surface characteristics is where a liquid flows
more easily on a rough surface than on a very
smooth surface.
 Film thickness: In general, the thinner the film, the
stronger the adhesive junction.
 Retention is the ability to hold two things firmly
together when they will not adhere to each other.
 Curing
• Auto-cured material hardens as the result of a
chemical reaction of the materials.
• Light-cured material does not harden until it has
been exposed to a curing light.

Restorative and Esthetic Materials
 Restorative: To replace or bring something
back to its natural appearance and function.
 Esthetic: To replace or bring something back to
its pleasing appearance.

Direct Restorations
 Restorative materials that are applied to the
tooth while the material is pliable and able to
carve and finish.
• Amalgam
• Composite resins
• Glass ionomer
• Intermediate restorative materials
• Tooth-whitening products

Amalgam
 Amalgam is a safe, affordable, and durable
material that is used predominantly to restore
premolars and molars (Figure 43-8).

Fig. 43-8 Packing an amalgam carrier.

Indications for Using Amalgam
 In individuals of all ages.
 In stress-bearing areas of the mouth.
 When there is severe destruction of tooth
structure.
 As a foundation.
 When personal oral hygiene is poor.
 When moisture control is problematic.
 When cost is an overriding patient concern.

Indications for Not Using Amalgam
 Esthetics is important.
 Patient has a history of allergy to mercury or
other amalgam components.
 The cost of other restorative materials or
treatment options is not a factor.

Chemical Makeup of Amalgam
 Mercury (43% to 54%)
 Alloy powder (57% to 46%)
• Silver, which gives it its strength.
• Tin for its workability and strength.
• Copper for its strength and corrosion
resistance.
• Zinc to suppress oxidation.

Issues Concerning Amalgam
 Harm to patients: Essentially harmless.
 The exception is with patients who have many
amalgam restorations, or a high sensitivity to
metals.
 Harm to Dental Personnel: Health concerns
with high exposure to mercury, not amalgam.
• Tremors
• Kidney dysfunction
• Depression
• Nervous system disorders

Amalgam Hygiene
 Do not contact mercury with your skin.
 Protect against spillage during trituration.
 Keep lid closed during trituration.
 Do not discard scrap amalgam into waste
containers.
 Collect all scrap amalgam and store under water
or photographic fixer solutions in a closed
container.

Preparation of Amalgam
 Capsules (600 mg of alloy): For small or
single-surface restorations.
 Capsules (800 mg of alloy): For larger
restorations.
 Trituration: The process by which the
mercury and alloy are mixed together to form
the mass of amalgam.

Direct Application of Amalgam
1. Mixed amalgam placed in amalgam well.
2. Amalgam carried to the prepared tooth.
3. Amalgam placed in increments in the
prepared tooth.
4. Each increment is condensed immediately.
5. Carvers are used to carve anatomy into the
amalgam.
6. A burnisher is used to smooth the amalgam.
7. The new restorations occlusion is checked.

Composite Resins
 Becoming the most widely accepted material of
choice by dentists and patients because of their
esthetic qualities and new advances in their
strength (Figure 43-13).

Fig. 43-13 Resins supplied in a syringe.

Indications for Using Composite Resins
 Withstand the environments of the oral cavity.
 Be easily shaped to the anatomy of a tooth.
 Match the natural tooth color.
 Be bonded directly to the tooth surface.

Chemical Makeup of Composite Resins
 Resin matrix
• Dimethacrylate, referred to as BIS-GMA
• Monomer used to make synthetic resins
• Polymerization additives
• Allow the material to take form through a
chemical process
• Initiator
• Accelerator
• Retarder
• Ultraviolet (UV) stabilizers

Chemical Makeup of Composite
Resins-cont’d
 Fillers Add the strength and characteristics
necessary for use as a restorative material.
 Inorganic fillers
• Quartz
• Glass
• Silica
• Colorants

Chemical Makeup of Composite
Resins-cont’d
 A coupling agent strengthens the resin by
chemically bonding the filler to the resin
matrix.
• Organosilane compound

Types of Composites
 Macrofilled composites contain the largest of
filler particles, providing greater strength but a
duller, rougher surface.
 Microfilled composites: The inorganic filler is
much smaller and is capable of producing a
highly polishee, finished restoration, which is
used primarily in anterior restoration.
 Hybrid composites contain both macrofill and
microfill particles.

Polymerization of Composite Resins
 The process in which the resin material is
changed from a plastic state into a hardened
restoration.
• Auto-Cured
• Light-Cured

Direct Application of Composite Resins
1. Select the shade of the tooth.
2. Express the needed amount of material onto
the treated pad or in the light-protected well.
3. Material placed in increments.
4. Material is light-cured.
5. Material is finished and polished.

Steps in Finishing a Composite Restoration
1. Reduction of the material is completed by the
use of a white stone or a finishing diamond.
2. Fine finishing is completed with carbide
finishing burs and diamond burs.
3. Polish with medium discs and finish with the
superfine discs.
4. Finishing strips assist in the polishing of the
interproximal surfaces.
5. Use polishing paste with a rubber cup.

Glass Ionomer Materials
 Glass ionomer is a versatile material with
chemical properties allowing it to be a
restorative material, liner, bonding agent, and
permanent cement.

Indications for Using Glass Ionomers
 Primary teeth.
 Final restorations in non-stress areas.
 Intermediate restorations.
 Core material for a buildups.
 Long-term temporary restorations.

Qualities of Glass Ionomers
 The ability to chemically bind to the teeth.
 No need to prepare the tooth structure as
extensively as for preparing for an amalgam or
composite resin.
 The release of fluoride after its final setting.

Properties of Glass Ionomers
 Glass Ionomer
 Glass
• Ceramic particles
• Glassy matrix
 Acrylic acid
 Tartaric acid
 Maleic acid
 Metal-reinforced glass ionomer
• Silver-tin alloy + Glass ionomer

Supply of Glass Ionomers
 Powder and Liquid: Manually mixed together
on a treated paper pad.
 Light-Protected Tubes: Dispensed onto a
treated paper pad.
 Paste/Paste System: Mixed for application.
 Premeasured Capsule: Triturated for
application.

Temporary Restorative Materials
 Designed to maintain or restore function to a
tooth or teeth and keep the patient
comfortable for a period of time.

Indications for Using a Temporary
Restorative Material
 Reduce sensitivity and discomfort of a tooth to
determine its diagnosis.
 Maintain the function and esthetics of a tooth
until a permanent restoration can be placed.
 Protect the margins of a prepared tooth that
will receive a permanent casting at a later time.
 Prevent shifting of the adjacent or opposing
teeth because of open space.

Intermediate Restorative Materials (IRM)
 Composition:
• Zinc-Oxide gives strength and durability.
• Eugenol has a sedative effect.

Indications for Using IRM
 Restoration of primary teeth
 Restorative emergencies
 Caries management program
 Supply of IRM
• Powder/liquid
• Premeasured capsules

Provisional Restorative Materials
 Restorative material that covers the major
portion, if not the entire clinical portion of a
tooth or several teeth for a period of time.

Types of Materials Used
 Auto-cured acrylic (methylmethacrylate)
 Light-cured resin
 Process of application
• Material is placed in either an alginate
impression or a vacuum-formed tray.
• Material is seated over the prepared tooth
and allowed to cure.
• Occlusion is adjusted.
• Material is cemented in place with temporary
cement.

Tooth Whitening Materials
 The process of applying a material on anterior
teeth for a prescribed period of time to whiten
the color of one’s teeth.

Indications for Using Tooth-Whitening
Products
 Teeth discolored
 Aging
 Consumption of staining substances
 Trauma
 Tetracycline staining
 Excessive fluoride
 Nerve degeneration
 Old restorations

Tooth-Whitening Products
 Carbamide Peroxide: When the carbamide
peroxide breaks down, oxygen enters the
enamel and dentin and bleaches the colored
substances.
 Concentrations: 10%, 16%, 22%

Indirect Restorations
 Types of dental restorations that dental
laboratory technicians create in the dental
laboratory.
 These restorations are also referred to as
castings, cannot be reshaped, and are carved
once they are in this stage.

Gold Alloys
 By combining gold with other metals to form
an alloy, it creates the characteristics and
hardness required as an excellent choice for an
indirect restoration.
• Gold
• Palladium
• Platinum

Types of Casting Alloys
 Soft, Type I alloys are used for casting inlays
subject to slight stress during mastication.
 Medium, Type II alloys can be used for
practically all types of cast inlays and possibly
posterior bridge abutments.
 Hard, Type III alloys are acceptable for
inlays, full crowns, three-quarter crowns, and
anterior or posterior bridge abutments.
 Extra-hard, Type IV alloys are designed for
cast-removable partial dentures.

Ceramics
 Ceramics are compounds that involve a
combination of metallic and nonmetallic
elements, creating strength and aesthetics.

Types of Ceramic Restorations
 Porcelain fused to metal (PFM)
 Porcelain bonded to metal (PBM)
 Ceramco-metal restorations
 Porcelain-metal restorations (P-M)

Porcelain
 Type of ceramic that is most commonly used in
dentistry. It combines strength, translucence
and the ability to match the natural tooth color.

Indications for Using Porcelain
 The shading of colors matches the tooth color
well.
 It esthetically improves the appearance of
anterior teeth.
 It has the strength of metal.
 The material is a good insulator.
 The material has a low coefficient of thermal
expansion.

Dental materials (C)

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