Transcript MDA Ch 44 PP

Dental Liners, Bases,
and Bonding Systems
Chapter 44
Copyright © 2005 by Elsevier Inc. All rights reserved.
Introduction
Dental liners, bases, and bonding systems
are a supplemental classification of dental
materials that provide additional
protection for the health and well-being
of the tooth being restored.
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Prepared Tooth Structures
• Design of the Cavity Preparation
– Gives strength within the tooth
– Helps determine how the tooth will hold
the restoration in place
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Pulpal Responses
Types of Stimulus
Examples of Stimulus
Physical
Thermal, electrical
Mechanical
Handpiece,
traumatic occlusion
Chemical
Acid from dental
materials
Biologic
Bacteria from saliva
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Dental Liners
Dental liners provide a thin barrier to
protect the pulpal tissue from irritation
caused by physical, mechanical,
chemical and biologic elements.
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Calcium Hydroxide
• Indications for Use
– Protects the pulp from chemical irritation by
its sealing ability.
– Stimulates the production of reparative or
secondary dentin.
– Compatible with all types of restorative
materials.
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Calcium Hydroxide-cont’d
• Application Process
– May be an advanced function in your state
– Placed directly over the deepest portion of
the preparation
– Placed only on dentin
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Fig. 44-1 Location for placement of calcium hydroxide
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Varnish
A liquid consisting of one or more resins
in an organic solvent applied to the
internal preparation structure.
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Varnishes
• Indications for Use*
– Seal dentinal tubules
– Reduce leakage around a restoration
– Act as a barrier to protect the tooth from
highly acidic cements such as zinc phosphate
* This material is contraindicated in its use under composite
resins and glass ionomer restorations
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Varnishes-cont’d
• Application Process
– Applied with either a small disposable
applicator or cotton pellet
– Thin coating of varnish placed on the
internal walls, floor, and margin of a
cavity preparation
– Allowed to air dry
– A second application is recommended
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Fig. 44-3 Location for placement of cavity varnish
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Dentin Sealer
• Indications for Use
– Treat or prevent hypersensitivity
– Used instead of a varnish
– Seal the dentinal tubules
– Ideal for use under all indirect restorations
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Dentin Sealer-cont’d
• Application Process
– Use material sparingly
– Do not allow to contact soft tissues
(HEMA and glutaraldehyde)
– Apply the dentin sealer with the cotton-tipped
applicator
– Apply over all areas of exposed dentin
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Dental Bases
• Dental bases provide different types
of pulpal protection:
– Protective Base: Protects the pulp from a large
restoration.
– Insulating Base: Protects the tooth from
thermal shock.
– Sedative Base: Soothes a pulp that has been
damaged by decay or irritated by mechanical
means.
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Types of Base Materials
Zinc Oxide Eugenol (ZOE)
Zinc Phosphate
Polycarboxylate
Glass Ionomer
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Fig. 44-5 Location for placement of a base
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Dental Bonding
Dental bonding improves retention by
creating a micromechanical retention
between the tooth structure
and the restoration.
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Enamel Bonding
• Enamel bonding is placed directly
on the intact enamel surface.
• Examples of Enamel Bonding
– Sealants
– Bonded orthodontic brackets
– Resin-bonded bridges
– Bonded veneers
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Dentin Bonding
• Dentin bonding is placed on the prepared
dentin for the bonding of a restorative
material to tooth structure.
• Smear Layer
– Thin layer of debris
– “Nature's bandage”
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Etching Systems
• Etching Systems remove the smear layer
in preparation for bonding.
• Supplied as:
– Liquid/Gel
– Maleic acid
– Phosphoric acid
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Clinical Application of the Etchant and
Bonding Systems
• Plaque or debris is removed before the
bonding process.
• Etchant is applied to remove the smear layer.
• Rinsing and Drying of tooth structure
(avoid overdrying etched teeth).
• Bonding solution covers all surfaces.
• Too much bonding is better than too little.
• Contamination with saliva requires the entire
procedure to be redone.
• Allow time for bonding material to mature
before completing the restoration.
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Table 44-1 Supplementary Dental Materials
and Application in Order of Use
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