dental liners, bases and bonding Ch. 44

Prepared Tooth Structures
Design of the cavity preparation gives strength within the tooth & helps determine how the tooth will hold the restoration in place.
Pulpal Responses (sensitivities & discomforts)
Pulp sensitivities and discomforts that the patient may experience after a restoration. (Physical, Mechanical, Chemical, Biologic stimuli)
Physical Stimuli
Thermal (hot /cold), electrical (fork, foil)
Mechanical Stimuli
Handpiece (vibration from dentist drill), traumatic occlusion ("bite" does not occlude properly & added pressure is placed in a specific area)
Chemical Stimuli
Acid from dental materials (zinc phosphate (ZOE); pH 0-14, 7 neutral)
Biologic Stimuli
Bacteria from saliva.
Dental Liners
Provide thin barrier that protects the pulpal tissue from irritation cased by physical, mechanical, chemical & biologic element.
Calcium Hydroxide (CaOH)
Protects pulp from chemical irritation by sealing, stimulates production of reparative or secondary dentin, compatible with many restorative materials, Dycal (type of liner that is a 2-paste system, catalyst and base). *Apply only on dentin directly over deepest portion of the preparation.
Used to seal dentinal tubules, reduce leakage around restoration, barrier to protect tooth from acidic cements like zinc phosphate. Inadvisable to use under composite & glass ionomer cements. *Apply w/cotton pellet a thin coat on walls, floor, & margin of cavity, apply second coat.
Dentin Sealer
Used to tx or prevent hypersensitivity, seal dentinal tubules. Used instead of a varnish. Ideal for use under all indirect restorations. *Apply sparingly with cotton tipped applicator over all areas of the exposed dentin. Don't allow contact w/ soft tissues (HEMA & glutaraldehyde),
Dental Bases
Provide pulpal protection in three ways: protective bases, insulating bases, sedative bases.
Protective base
Protect the pulp before the restoration is placed.
Insulating base
Protect the tooth from thermal shock.
Sedative base
Soothe a pulp that has been damaged by decay or irritated by mechanical means. Types of base materials are Zinc oxide-eugenol, Zinc phosphate, Polycarboxylate, Glass ionomer.
Zinc oxide-eugenol (ZOE)
An insulating and sedative base. Made with eugenol, an oil from cloves and soothing on painful pulp. Can't be used under composite resins or glass ionomers.
Zinc phosphate
Excellent thermal insulator. Phosphoric acid can be irritating to pulp, so a liner is needed under the zinc phosphate base.
Selected for protective and insulating qualities. Nonirritating to the pulp and can go under all types of direct and indirect restorations. *A base is much thicker than a liner, varnish, or desensitizer to act as a buffer between the pulp and restorative material. Entire pulpal covered to 1-2mm thicknes
Critical for enamel and dentin surfaces to form a better chemical bond between the tooth and restoration. System to remove the smear layer in preparation for bonding. Supplied as:Liquid/Gel
Maleic acid, Phosphoric acid.
Dental bonding
Improves retention by creating a micromechanical retention between the tooth structure and the restoration.
Enamel bonding
Placed directly onto the intact enamel surface. Ex: Sealants, bonded orthodontic brackets, resin-bonded bridges, bonded veneers.
Dentin bonding
Placed on prepared dentin in order to bond.
Smear layer (Thin layer of debris,"Nature's bandage")
Restorative Materials
To replace or bring something back to its natural appearance and function.
Esthetic Materials
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.
A safe, affordable, and durable material that is used to restore premolars and molars.
Process where the mercury and alloy are mixed together to form the mass of amalgam.
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. Match natural tooth, bond directly to tooth
Macrofilled composites
Contain the largest of filler particles, providing greater strength but a duller, rougher surface.
Microfilled composites
Inorganic filler is much smaller and is capable of producing a high polish, finished restoration, which is used primarily in anterior restoration.
Hybrid composites
Contain both macrofill and microfill particles.
Polymerizaton of Composite Resins
Process in which the resin material is changed from plastic state into a hardened restoration. Auto-cured, light-cured.
Glass Ionomer Materials
A versatile material with chemical properties allowing it to be a restorative material, liner, bonding agent, and permanent cement. Use for primary teeth, non-stress areas, intermediate restorations, core material for buildups, long term temporary restorations.
Temporary Restorative Materials
Designed to maintain or restore function to a tooth or teeth and keep the patient comfortable for a period of time.
Intermediate Restorative Materials (IRM)
Composed of zinc-oxide for strength and durability, and eugenol which has a sedative effect. Used to restore primary teeth, emergencies, caries management. IRM come in premeasured capsules of powder/liquid.