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. Copyright © 2005 by Elsevier Inc. All rights reserved.

Prepared Tooth Structures Design of the Cavity Preparation Gives strength within the tooth Helps determine how the tooth will hold the restoration in place Copyright © 2005 by Elsevier Inc. All rights reserved.

Pulpal Responses Types of Stimulus Examples of Stimulus Physical Thermal, electrical Mechanical Handpiece, traumatic occlusion Chemical Acid from dental materials Biologic Bacteria from saliva Copyright © 2005 by Elsevier Inc. All rights reserved.

Dental Liners Dental liners provide a thin barrier to protect the pulpal tissue from irritation caused by physical, mechanical, chemical and biologic elements. Copyright © 2005 by Elsevier Inc. All rights reserved.

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. Copyright © 2005 by Elsevier Inc. All rights reserved.

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 Copyright © 2005 by Elsevier Inc. All rights reserved.

Fig. 44-1 Location for placement of calcium hydroxide Copyright © 2005 by Elsevier Inc. All rights reserved.

Varnish A liquid consisting of one or more resins in an organic solvent applied to the internal preparation structure. Copyright © 2005 by Elsevier Inc. All rights reserved.

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 Copyright © 2005 by Elsevier Inc. All rights reserved.

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 Copyright © 2005 by Elsevier Inc. All rights reserved.

Fig. 44-3 Location for placement of cavity varnish Copyright © 2005 by Elsevier Inc. All rights reserved.

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 Copyright © 2005 by Elsevier Inc. All rights reserved.

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 Copyright © 2005 by Elsevier Inc. All rights reserved.

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. Copyright © 2005 by Elsevier Inc. All rights reserved.

Types of Base Materials Zinc Oxide Eugenol (ZOE) Zinc Phosphate Polycarboxylate Glass Ionomer Copyright © 2005 by Elsevier Inc. All rights reserved.

Fig. 44-5 Location for placement of a base Copyright © 2005 by Elsevier Inc. All rights reserved.

Dental Bonding Dental bonding improves retention by creating a micromechanical retention between the tooth structure and the restoration. Copyright © 2005 by Elsevier Inc. All rights reserved.

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 Copyright © 2005 by Elsevier Inc. All rights reserved.

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” Copyright © 2005 by Elsevier Inc. All rights reserved.

Etching Systems Etching Systems remove the smear layer in preparation for bonding. Supplied as: Liquid/Gel Maleic acid Phosphoric acid Copyright © 2005 by Elsevier Inc. All rights reserved.

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.       Copyright © 2005 by Elsevier Inc. All rights reserved.

Table 44-1 Supplementary Dental Materials and Application in Order of Use Copyright © 2005 by Elsevier Inc. All rights reserved.