Transcript Dental Cements Chapter 45

Chapter 45
Dental Cements
Copyright 2003, Elsevier Science (USA).
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Produced in the United States of America
ISBN 0-7216-9770-4
Copyright 2003, Elsevier Science (USA). All rights reserved.
Introduction
Dental cements are a classification of dental
materials that are continually used in dentistry.
The American Dental Association and the
International Standards Organization (ISO) have
teamed up to classify dental cements according to
their properties and their intended uses in
dentistry.
Copyright 2003, Elsevier Science (USA). All rights reserved.
Classification of Cements
 Type I: Luting agents that include
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permanent and temporary cements.
Type II: Restorative applications.
Type III: Liner or base applications.
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Luting Agent
 A material that acts as an adhesive to hold
together the casting to the tooth structure.
Luting agents are designed to be either
permanent or temporary.
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Permanent Cement
 For the long-term cementation of cast
restorations such as inlays, crowns, bridges,
laminate veneers, and orthodontic fixed
appliances.
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Temporary Cement
 Temporary cements are used when the
restoration will have to be removed. Most
commonly, temporary cement is selected for
the placement of provisional coverage.
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Variables Affecting Cements
 Mixing time
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• Make sure to follow the manufacture’s
directions for the mixing time, working time,
and delivery time.
Humidity
• If the clinical area is warm or humid,
premature exposure of the cement to these
environments can create a loss of water from
the liquid or an addition of moisture to the
powder.
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Variables Affecting Cements-cont’d
 Powder to liquid ratio

• Incorporating too much or too little powder
will alter the consistency.
Temperature
• Some types of cements put off an
exothermic reaction.
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Mixing Dental Cements
 Before mixing, read and carefully follow the
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
manufacturer's directions for the brand being
mixed.
Determine the use and then measure the powder
and liquid according to the manufacturer's
instructions.
Place the powder toward one end of the glass
slab or paper pad and the liquid toward the
opposite end (the space between allows room for
mixing).
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Mixing Dental Cements-cont’d
 Divide the powder into increments.
 When increment sizes vary, the smaller
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increments are used first.
Incorporate each powder increment into the
liquid and then mix thoroughly.
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Types of Cements
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Zinc-oxide eugenol
Zinc phosphate
Polycarboxylate
Glass ionomer
Composite resin
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Zinc Oxide Eugenol
 Chemical Makeup
• Liquid: Eugenol, H2O, acetic acid, zinc
acetate, and calcium chloride.
• Powder: Zinc oxide, magnesium oxide,
and silica.
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Types of Zinc-Oxide Eugenol
 Type I

• Lacks strength and long-term durability
and is used for temporary cementation of
provisional coverage.
Type II
• Has reinforcing agents added and is used
for the permanent cementation of cast
restorations or appliances.
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Supply of Zinc-Oxide Eugenol
 Liquid/Powder

• Mixed on an oil-resistant paper pad.
• Mixing time ranges from 30 to 60 seconds.
• Setting time in the mouth ranges from 3 to
5 minutes.
Paste
• Supplied as a two-paste system as
temporary cement.
• Pastes are dispensed in equal lengths on a
paper pad and mixed.
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Zinc Phosphate
 Chemical Makeup
• Liquid: Phosphoric acid, aluminum
phosphate, and water.
• Powder: Zinc oxide, magnesium oxide,
and silica.
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Types of Zinc Phosphate
 Type I (fine grain)

• Used for the permanent cementation of
cast restorations such as crowns, inlays,
onlays, and bridges. This material creates
the very thin film layer that is necessary for
accurate seating of castings.
Type II (medium grain)
• Recommended for use as an insulating
base for deep cavity preparations.
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Supply of Zinc Phosphate
 Powder/liquid
• Powder is divided into increments that vary
in size.
• It is critical that the powder be added to
the liquid in very small increments.
• Cement must be spatulated slowly over a
wide area of a cool, dry, thick glass slab to
dissipate the heat.
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Polycarboxylate Cements
 Chemical Makeup
• Liquid: Polyacrylic acid, itaconic acid,
maleic acid, tartaric acid, and water
• Powder: Zinc oxide
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Use of Polycarboxylate
 Used as a permanent cement for cast
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restorations, stainless steel crowns, and
orthodontic bands.
Used as a nonirritating base under both
composite or amalgam restorations.
Used as an intermediate restoration.
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Supply of Polycarboxylate
 Powder/liquid
• Liquid may be measured by using either
the plastic squeeze bottle or the calibrated
syringe-type liquid dispenser.
• Liquid has a limited shelf life because it
thickens as its water evaporates.
• Mixed on a nonabsorbent paper pad.
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Glass Ionomer
 Chemical Makeup
• Liquid: Itaconic acid, tartaric acid, maleic
acid, and water.
• Powder: Zinc oxide, aluminum oxide, and
calcium.
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Types of Glass Ionomer
 Type I
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• For the cementation of metal restorations
and direct-bonded orthodontic brackets.
Type II
• Designed for restoring areas of erosion
near the gingiva.
Type III
• Used as liners and dentin bonding agents.
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Benefits of Glass Ionomer
 Powder is an acid-soluble calcium. The slow
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release of fluoride from this powder aids in
inhibiting recurrent decay.
Causes less trauma or shock to the pulp than
many other types of cements.
Low solubility in the mouth.
Adheres to a slightly moist tooth surface.
Has a very thin film thickness, which is excellent
for seating ease.
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Supply of Glass Ionomer
 Powder/liquid
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• Mixed manually on a paper pad or a cool,
dry glass slab.
• Glass slab increases the working time of
the cement.
Premeasured capsules
• Triturated and expressed through a
dispenser.
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Composite Resin
 Chemical Makeup
• Physical properties are comparable to those
of composite resins.
• Low film thickness.
• Insoluble in the mouth.
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Uses of Composite Resin
 Cementation of ceramic or resin inlays and
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onlays.
Cementation of ceramic veneers.
Cementation of orthodontic bands.
Direct bonding of orthodontic brackets.
Cementation of all metal castings.
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Supply of Composite Resin
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Powder and liquid mix
Syringe-type applicator
Base and catalyst
Light cure/dual cure system
• Recommended portions of either
application are dispensed onto a paper pad
and mixed rapidly with a spatula.
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Cement Removal
 Operator preparedness and knowledge
• Instruments selected for the procedure:
Explorer, mouth mirror, black spoon.
• Use of a fulcrum.
• Use of dental floss in and around the
embrasure areas.
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