Restorative and Esthetic Dental Materials Chapter 43 Copyright

Restorative and Esthetic Dental Materials Chapter 43 Copyright © 2005 by Elsevier Inc. All rights reserved.

Introduction Restorative dental materials fulfill an important role in the way dentistry is delivered today. Copyright © 2005 by Elsevier Inc. All rights reserved.

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 – Must conform to function Copyright © 2005 by Elsevier Inc. All rights reserved.

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

Types of Stress and Strain • Tensile Stress – Pulls and stretches the material. • Compressive Stress – Pushes the material together. • Shear Stress – The breakdown of the material. Copyright © 2005 by Elsevier Inc. All rights reserved.

Fig. 43 -1 Types of Stress and Strain Copyright © 2005 by Elsevier Inc. All rights reserved.

Thermal Changes • A change in temperature in the oral cavity results from a hot or cold product. • Contraction and Expansion – Dental materials will contract or expand at their own rate. – Changes in temperature can cause a dental material to pull away from the tooth causing • Microleakage • Faulty restoration Copyright © 2005 by Elsevier Inc. All rights reserved.

Electrical Properties • An electrical current, or galvanic action, is created when two different or dissimilar metals are present in the oral cavity. • Conditions For This To Occur – Saliva – Two metallic components of different composition – Electrical current – Galvanic action, or shock, is the coming together of all conditions Copyright © 2005 by Elsevier Inc. All rights reserved.

Corrosive Properties • Reaction that a metal has when it comes into contact with corrosive products. • Solubility – The degree to which a substance will dissolve in a given amount of another substance. Copyright © 2005 by Elsevier Inc. All rights reserved.

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

Application Properties-cont’d • Surface characteristics - 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 - 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. Copyright © 2005 by Elsevier Inc. All rights reserved.

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 a pleasing appearance. Copyright © 2005 by Elsevier Inc. All rights reserved.

Direct Restorations • Restorative materials are applied to the tooth while the material is pliable and able to carve and finish. – Amalgam – Composite resins – Glass ionomers – Intermediate restorative materials – Tooth-whitening products Copyright © 2005 by Elsevier Inc. All rights reserved.

Dental Amalgam is a safe, affordable, and durable material used predominantly to restore premolars and molars. Copyright © 2005 by Elsevier Inc. All rights reserved.

Fig. 43 -6 Example of a Class II amalgam restoration Copyright © 2005 by Elsevier Inc. All rights reserved.

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 for a crown • When personal oral hygiene is poor • When moisture control is problematic • When cost is an overriding patient concern Copyright © 2005 by Elsevier Inc. All rights reserved.

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

Indications for Using 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. Copyright © 2005 by Elsevier Inc. All rights reserved.

Fig. 43 -7 Mercury and Alloy powder in is purest form, then triturated (From Hatrick CD, Eakle WS, Bird WF: Dental materials: clinical applications for dental assistants and dental hygienists, St. Louis, 2003, Saunders. ) Copyright © 2005 by Elsevier Inc. All rights reserved.

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 Copyright © 2005 by Elsevier Inc. All rights reserved.

Amalgam Hygiene Guidelines • 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. Copyright © 2005 by Elsevier Inc. All rights reserved.

Preparation of Amalgam • Capsules – (600 mg of alloy): For small or single-surface restorations – (800 mg of alloy): For larger restorations • Activator: Used to break the separating membrane in the capsule • Trituration: The process by which the mercury and alloy are mixed together to form the mass of amalgam Copyright © 2005 by Elsevier Inc. All rights reserved.

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

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

Fig. 43 -14 Example of a composite resin restoration. (Courtesy Premier Dental Products. ) Copyright © 2005 by Elsevier Inc. All rights reserved.

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 Copyright © 2005 by Elsevier Inc. All rights reserved.

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

Composition of Composite Resins-cont’d • Fillers add the strength and characteristics necessary for use as a restorative material. • Inorganic Fillers – Quartz – Glass – Silica – Colorants Copyright © 2005 by Elsevier Inc. All rights reserved.

Composition of Composite Resins-cont’d • Coupling Agent strengthens the resin by chemically bonding the filler particles to the resin matrix – Organosilane compound Copyright © 2005 by Elsevier Inc. All rights reserved.

Types of Composites • Macrofilled Composites – Contains the largest of filler particles, providing greater strength but a duller, rougher surface. Rarely used today. • Microfilled Composites – The inorganic filler is much smaller and is capable of producing a highly polished, finished restoration, which is used primarily in anterior restoration. • Hybrid Composites – Contain both macrofill and microfill particles. Copyright © 2005 by Elsevier Inc. All rights reserved.

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 Copyright © 2005 by Elsevier Inc. All rights reserved.

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 transferred in increments. 4. Material is light-cured. 5. Material is finished and polished. Copyright © 2005 by Elsevier Inc. All rights reserved.

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

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

Indications for Using Glass Ionomers • Primary teeth. • Final restorations in nonstress areas. • Intermediate restorations. • Core material for a buildup. • Long-term temporary restorations. Copyright © 2005 by Elsevier Inc. All rights reserved.

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 Copyright © 2005 by Elsevier Inc. All rights reserved.

Composition of Glass Ionomers • Glass – Ceramic particles – Glassy matrix • Acrylic acid • Tartaric acid • Maleic acid • Metal-reinforced glass ionomer – Silver-tin alloy + Glass ionomer Copyright © 2005 by Elsevier Inc. All rights reserved.

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

Temporary Restorative Materials Designed to maintain or restore function to a tooth or teeth and keep the patient comfortable for a period of time Copyright © 2005 by Elsevier Inc. All rights reserved.

Fig. 43 -20 Placement of a temporary restoration Copyright © 2005 by Elsevier Inc. All rights reserved.

Indications for Using IRM • 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. Copyright © 2005 by Elsevier Inc. All rights reserved.

Composition of IRM • Zinc-Oxide gives strength and durability. • Eugenol has a sedative effect. • Supply of IRM – Powder/liquid – Premeasured capsules Copyright © 2005 by Elsevier Inc. All rights reserved.

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

Fig. 43 -21 Example of an acrylic resin temporary Copyright © 2005 by Elsevier Inc. All rights reserved.

Fig. 43 -22 Acrylic resin supplied in different forms (From Hatrick CD, Eakle WS, Bird WF: Dental materials: clinical applications for dental assistants and dental hygienists, St. Louis, 2003, Saunders. ) Copyright © 2005 by Elsevier Inc. All rights reserved.

Process of Application • Material is mixed and placed in either an alginate impression or a vacuumformed tray. • Seated over the prepared tooth and allowed to cure. • Occlusion and margins are adjusted. • Material is cemented in place with temporary cement. Copyright © 2005 by Elsevier Inc. All rights reserved.

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

Fig. 43 -23 Before and after in tooth whitening Copyright © 2005 by Elsevier Inc. All rights reserved.

Indications for Using Tooth-Whitening Products • Teeth discolored • Aging • Consumption of staining substances • Trauma • Tetracycline staining • Excessive fluoride • Nerve degeneration • Old restorations Copyright © 2005 by Elsevier Inc. All rights reserved.

Tooth-Whitening Products • Peroxide-Based Gel – The peroxide breaks down, oxygen enters the enamel and dentin and bleaches the colored substances. – Concentrations: 10%, 16%, 22% Copyright © 2005 by Elsevier Inc. All rights reserved.

Treatment Options • In-Office Treatment – Professionally applied – Fastest results – Most expensive • At-Home Treatment – Custom fitted tray – Follow a regimen • Over-the-Counter – Strips – Paint on Copyright © 2005 by Elsevier Inc. All rights reserved.

Indirect Restorations Types of dental restorations that the dental laboratory technician creates in the dental laboratory. These restorations are referred to as castings, which cannot be reshaped, and carved once they are in this stage. Copyright © 2005 by Elsevier Inc. All rights reserved.

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 Copyright © 2005 by Elsevier Inc. All rights reserved.

Fig. 43 -26 Gold posterior crown Copyright © 2005 by Elsevier Inc. All rights reserved.

Types of Casting Alloys • Soft, Type I Alloy – Used for casting inlays subject to slight stress during mastication • Medium, Type II Alloy – Used for practically all types of cast inlays and possibly posterior bridge abutments • Hard, Type III Alloy – Acceptable for inlays, full crowns, three-quarter crowns, and anterior or posterior bridge abutments • Extra-hard, Type IV Alloy – Designed for cast-removable partial dentures Copyright © 2005 by Elsevier Inc. All rights reserved.

Ceramics are compounds that involve a combination of metallic and nonmetallic elements, creating strength and aesthetics. Copyright © 2005 by Elsevier Inc. All rights reserved.

Types of Ceramic Restorations • Porcelain fused to metal (PFM) • Porcelain bonded to metal (PBM) • Ceramco-metal restorations • Porcelain-metal restorations (P-M) Copyright © 2005 by Elsevier Inc. All rights reserved.

Porcelain • Type of ceramic that is most commonly used in dentistry. It combines strength, translucence and the ability to match the natural tooth color. Copyright © 2005 by Elsevier Inc. All rights reserved.

Fig. 43 -27 Example of a porcelain crown Copyright © 2005 by Elsevier Inc. All rights reserved.

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