Chapter 43 - Restorative and Esthetic Dental Materials

Galloy.

A nonmercury alloy that has been approved by the American Dental Association (ADA), but has not been researched for its potential because of the advancement of composite resins.

Curing of most dental material in the process of?

Placing a paste-type material into the tooth preparation for adaptation.

What term describes the process in which the resin material is changed from a plastic state, where it can be molded and shaped, into a hardened restoration?

Polymerization.

What type of ceramic, used most often in dentistry, combines strength, translucence, and the ability to match the natural tooth color?

Porcelain.

Would dental amalgam be placed in anterior or posterior teeth?

Posterior

What controversies exist with the mercury in dental amalgam?

Potential harm to patients from the mercury within the amalgams placed in their teeth. The toxicity level of mercury vapors affecting dental personnel exposed over a long period.

When were microfilled composites used?

Primarily in anterior restorations, for which smoothness and esthetics are of primary concern and class III restorations.

List the indications for the uses of amalgam.

Primary & permanent teeth Stress-bearing areas of the mouth Small to medium-sized cavities in the posterior teeth Severe destruction of tooth structure As a foundation for cast-metal, metal-ceramic, and ceramic restorations When a patient's commitment to personal oral hygiene is poor When moisture control is problematic When cost is an overriding patient concern.

Force.

Any push or pull on matter, which produces a stress and a strain

What is the average biting and chewing force in the posterior area of the mouth of persons with their natural teeth?

Approximately 170 pounds or approximately 28,000 pounds of pressure per square inch on a single cusp of a molar.

Esthetic.

Artistically pleasing and beautiful appearance.

What is the dental assistant's responsibility with regard to materials?

Assembling the setup for each material while being attentive to the manufacturer's recommended proportions and mixing techniques.

Describe these three forms of curing:

Auto-cured Light-cured Dual-cured

What are the main differences in the composition and classification of dental amalgam alloy powders?

Based on alloy particle shape and size, copper content, and zinc content.

Describe the composition of ceramic.

Composed of compounds of metallic and nonmetallic elements. They are made of a claylike material with a glaze that has metallic components to make it durable and able to withstand temperature changes.

How does the strength of composite resins compare with amalgam and gold alloy restorations?

Composite resins are not as strong as amalgams or gold alloy restorations but they are designed to meet the needs of the specific area of the tooth or mouth.

What dental materials are becoming the most widely accepted materials of choice by dentists and patients?

Composite resins.

What happens to a dental material when it is exposed to hot and cold?

Contraction and Expansion

These thermal changes are of major concern for two reasons:

Contraction and Expansion The need to protect the pulp from thermal shock from extreme differences in temperature

Macrofilled composites are also know as?

Conventional or traditional composites

Define malleability.

The ability of a material to withstand permanent deformation under compressive stress without sustaining permanent damage.

What allows for the polymerization of the composite resin?

The addition of fillers and coupling agents.

What improved the physical properties and esthetic qualities over the past several years?

The addition of resin which allows the material to be light-cured, auto-cured, or both.

What factors determine the strength and wear-resistance of the material and also influence the polished finish of the restoration?

The amount of filler, the particle size, and the types of fillers used.

What is the most important factor involved in selecting the shade?

The background lighting that is used.

Describe the traditional cavity preparation for amalgam restorations since amalgam and tooth structure do not adhere to each other.

The dentist uses a bur or hand (manual) cutting instruments to produce this retention form (creating a crevice in the tooth that the material can lock into). But, microleakage may occur between the material and the tooth if a bonding material is not placed to create a seal.

What factors are considered when selecting the most appropriate material?

The extent of the decay, the type of defect in the tooth, the condition of the entire mouth, the location of the restoration, and cost factors.

How is the provisional restoration constructed?

The material is placed in an alginate impression or in a vacuumed-formed tray and seated over the prepared tooth and allowed to cure. The occlusion is adjusted, and the temporary is polished and cemented in place with temporary cement.

Ductility.

The measure of the capacity of a metal to be stretched or drawn out by a pulling or tensile force without fracturing

Describe the sealed single use amalgam capsules.

They contain the proper ratio of metals in a sealed capsule. This ensures an accurate ratio and reduces the possibility of exposure to any of the materials.

Malleability allows a metal to be shaped into a?

Thin sheet or plate

Ductility allows a metal to be made into a?

Thin wire

What does the "flow" of a dental material allow during placement permit?

This allows the material to fill in the preparation of the tooth

What is the technical term for amalgam restorations?

"Silver fillings"

How long would you triturate Sybraloy?

13 seconds

What percentage of high-copper alloy is tin?

15-30%.

When someone drinks hot coffee (anything super hot) and then eats ice-cream (anything super cold), the temperature changes from what within the mouth in seconds?

150 degrees Fahrenheit to 100 degrees Fahrenheit (66 degrees C - 38 degrees C)

What is the mercury to alloy ratio of amalgam?

1:1.

What is the mixing time for the powder and liquid glass ionomer?

30 - 45 seconds.

What percentage of high-copper alloy is silver?

40-70%.

What portion of amalgam is mercury?

43-54%.

What portion of amalgam is alloy (mixture of metals) powder?

46-57%.

Capsules are available in?

600 mg of alloy - appropriate amount of material for a small or single-surface restoration 800 mg of alloy - Used for a larger restoration

What percentage of high-copper alloy is copper?

8-28%.

What term describes the non-noble metals used in the alloys?

A base metal.

What instruments are used to smooth the amalgam, making sure there are no irregularities in the restoration?

A burnisher.

Why is solubility in the mouth a concern?

A material that dissolves easily in the oral environment is of limited use due to the fact that it will wash away and leave the tooth structure exposed.

Describe base metals, including examples.

A metal of relatively low value that has inferior properties such as a lack of resistance to corrosion and tarnish. Examples include iron, tin, and zinc.

What type of temporary restoration may be used if a cusp is gone or the preparation of a tooth involves the gingival margin?

A provisional coverage material.

What covers a major portion, if not the entire clinical portion, of a tooth or several teeth for a longer period of time?

A provisional restorative material or temporary crown.

What is used to determine the correct shade?

A shade guide.

What separates the mercury and alloy in the capsule until they are ready to be mixed?

A thin membrane.

Solubility.

Ability to be dissolved

What is the function of the fillers in IRM?

Added to improve the strength and durability of the material.

What term describes force that causes unlike materials to adhere, or stick, to each other?

Adhesion.

Describe the recommended use of galloy.

After the tooth has been lined with a resin, and that an application of sealant be placed over the restoration.

What is the function of the pestle in the capsule?

Aids in the mixing process.

The main difference in the composition and classification of dental amalgam alloy powders are based on?

Alloy particle shape and size Copper content Zinc content

What materials are considered restorative and esthetic?

Amalgam, composite resins, glass ionomers, temporary restorative materials, and tooth-whitening products.

What restorative materials do not adhere directly to tooth structure?

Amalgam, or silver fillings, and cast metals.

What type of temporary restoration may be used for a lost filling or a small pit within the enamel?

An intermediate restorative material.

How do surface characteristics affect adhesion?

By influencing the wetting material of the material. A liquid flows more easily on a rough surface than on a very smooth surface.

Microfilled composites

Came about in the 1980s; the main difference noted with this type of composite resin was that it contained inorganic fillers that were much smaller than those in a macrofilled composites.

What is one of the most critical aspects of working with composite resins, and why?

Color-matching because if the correct shade is not selected, this will be apparent to the patient after the restoration is in place.

Why is retention an important concept in dentistry?

Dental restorations, casting, and appliances must be held in place with the use of materials and retention methods that are not harmful to the body.

What is the resin matrix component used as the foundation of resins?

Dimethacrylate, also known as BIS-GMA.

What term describes dental restorative materials that are applied to the tooth while the material is pliable and can be adapted, carved, and finished?

Direct restorations.

Strain.

Distortion or change produced as a result of stress

For what reasons do teeth become stained?

Due to aging, consumption of staining substances such as coffee, tea, colas, and tobacco; trauma, use of tetracycline, excessive fluoride, nerve degeneration, and aging of restorations.

A 1:1 mercury-to-alloy ratio is also known as?

Eames technique

What is used to finish a composite resin restoration?

Finishing burs and abrasive materials.

What are the four properties that must be considered in the application of a dental material?

Flow Adhesion Retention Curing

How does film thickness affect adhesion?

For adhesion to take place and remain permanent, the dental material selected that will join the tooth and restoration will require a thin film thickness. The thinner the film thickness, the stronger the adhesive junction.

When are metal reinforced glass ionomers used in dentistry?

For clinical application of core buildups, repair of fractured cusps and amalgam fillings in class I, II, and V cavities; as a base, and as an abutment for overdentures.

High-copper alloys

Frequently used Contain a higher percentage of copper than previous alloys

What term describes the electrical currents present in the oral cavity created when two different, or dissimilar, metals are present?

Galvanic action.

Silver.

Gives it its strength

What material represents one of the most versatile dental materials available?

Glass ionomers.

What materials make up the "glass" component of glass ionomers?

Glass, ceramic particles, and a glassy matrix.

Describe gold as a restorative material.

Gold in its purest form has the ability to resist tarnish and etching when exposed to harsh conditions in the mouth, but it is much too soft to use in cast dental restorations. However, it can be combined with other metals to form an alloy; this material provides the characteristics and hardness required of an indirect restoration.

What instruments are used to carve back the amalgam material to the tooth's normal anatomy?

Hand carving instruments.

Cured

Hardened Material

What terms describe the types of gold alloys?

Hardness, malleability, and adaptability.

What is the function of the eugenol in IRM?

Has a sedative effect on the pulp.

What happens when the peroxide-based product contacts the teeth?

It allows oxygen to enter the enamel and dentin, thereby whitening the colored substances.

Which type of composites contain a mixed range of particle sizes and can be polished smoother than macrofilled and has greater strength than microfilled with high wear resistance and excellent shading characteristics?

Hybrid composites used for IV and VI restorations.

A patient has discussed her concern over the large amount of amalgam fillings in her mouth, and she fears that the mercury may be harming her health. She has scheduled an appointment to discuss this with the dentist. If you were the dentist, how would you respond to this patient?

I would explain to her that when mercury is combined with other materials in dental amalgam, its chemical nature changes so that it is essentially harmless. The amount released in the mouth under the pressure of chewing and grinding is extremely small and presents no cause for alarm. In fact, this amount is less than what patients are routinely exposed to in food, water, and air.

How is IRM supplied?

In a powder and liquid that is mixed manually, or in premeasured capsules that are activated and then triturated.

How are composite resins packaged?

In a single-paste, lightproof syringe. The light-cured resins do not require mixing and are used directly as they come from the syringe. The paste will not harden until it has been exposed to the curing light.

How are glass ionomers supplied?

In bottles as a powder and liquid which are manually mixed together on a treated paper pad, or in light-protected tubes where the material is allowed to auto-cure for 10 to 15 minutes. The metal glass ionomer is supplied as a liquid or paste system or in premeasured capsules that are mixed or triturated for application.

Why is the cover on the amalgamator closed during trituration?

In order to prevent mercury vapors from escaping.

What materials are used to construct provisional restorations?

Include an auto-cure acrylic known as methylmethacrylate, or light-cured composite resin which has different properties than composite restorative materials.

What are the uses of glass ionomers?

Include as a restorative material, liner, bonding agent, and permanent cement.

What two forms of polymerization exist for composite resins?

Include auto-curing and light-curing.

List the cautions for placing glass ionomer.

Include avoiding water contamination contact with the material, being aware that when the material's glossy appearance has disappeared the setting stages have begun, and protecting the matrix band from the material as it will adhere to the metal band.

What materials are used for indirect restorations?

Include gold alloys and ceramic materials.

What noble metals are used for cast restorations?

Include gold, palladium, and platinum.

What combinations of ceramic-metal restorations are available?

Include porcelain fused to metal, porcelain bonded to metal, ceramico-metal, and porcelain metal.

What chain of procedures is involved in indirect restorations, or castings?

Include preparing the tooth, taking a final impression, waxing a pattern, investing the pattern, casting the restoration, finishing and polishing the casting, and cementing the restoration in place.

List the applications of glass ionomer restorative materials.

Include primary teeth, final restorations in nonstressed areas such as class V and root surfaces, intermediate restorations, core material for buildups, and provisional or long-term temporary restorations.

List the uses of temporary restorative materials.

Include reducing the sensitivity and discomfort of a tooth to determine its diagnosis, maintaining the function and esthetics of a tooth until a permanent restoration can be placed, protecting the margins of a prepared tooth that will receive a permanent casting at a later time, and preventing shifting of adjacent or opposing teeth caused by an open space.

List some common uses of IRM.

Include the restoration of primary teeth when permanent teeth are 2 years or less from eruption, restorative emergencies, and for caries management programs.

Why are porcelain materials chosen?

Include the shading of colors matches tooth color well, it improves the esthetic appearance of anterior teeth, the material has the strength of metal, it is a good insulator, and it has a low coefficient of thermal expansion.

What characteristics of dental materials affect adhesion?

Include wetting, viscosity, surface characteristics, and film thickness.

What is the composition of tooth-whitening products?

Includes a peroxide-based ingredient which comes in different concentrations.

What types of restorations does the dental laboratory technician create in the dental laboratory?

Includes indirect restorations or castings.

Hardness is a measure of the resistance of a metal to?

Indentation, scratching, or abrasion

How do indirect porcelain restorations compare with direct restorations, such as composite resins?

Indirect porcelain restorations are stronger than direct restorations, such as composite resins, due to the fact that laboratory fabrication techniques incorporate heat and pressure.

What additional additives are included?

Initiator, the accelerator, the retarder, and the ultraviolet (UV) light stabilizers.

Stress.

Internal reaction or resistance to an externally applied force

What materials make up the "ionomer" component of glass ionomers?

Ion-crossed-link polymers such as acrylic acid, tartaric acid, and maleic acid.

Corrosion.

Is the reaction that occurs within a metal when it is exposed to corrosive factors such as temperature, humidity, and saline. Certain foods contain metallic forms that can cause corrosion of a material. Most corrosion is only surface discoloration and can be easily removed with polishing agents.

Curing

Is the setting process of a dental material that is initiated by a chemical reaction or by light in a blue wave spectrum.

What is an advantage of using glass ionomer as a restorative material?

It has the ability to bind chemically, not mechanically, to the teeth, so the need to prepare the tooth structure is not as extensive as for amalgam or composite.

What is the disadvantage of galloy?

It is sensitive to moisture, which can cause corrosion and expansion.

List the criteria for new dental materials.

It must not be poisonous or harmful to the body It must not be harmful or irritating to the to the tissues of the oral cavity It must resemble the natural dentition as closely as possible so as to be esthetically pleasing It must be easily formed and placed in the mouth to restore the mouth's natural contour It must conform and function despite limited access, wet conditions, and poor visibility.

What type of composite contains the largest filler particles, providing greater strength but a duller, rougher surface?

Macrofilled, or conventional or traditional, composites that were used in the 1960s and 1970s that were self-cured.

Light-cured

Material does not harden until it has been exposed to a curing light. This allows a more flexible working time.

What characteristics allow dental materials to withstand the oral environment as well as allow for easy application?

Mechanical properties Thermal changes Electrical properties Corrosive properties Solubility Application properties.

Composites are classified by practical size as?

Megafill Macrofill Midifill Minifill Microfill Nanofill

Which type of composites contains much smaller filler particles and are capable of producing a highly polished finished restoration?

Microfilled composites that are UV-cured.

What may be the result of different rates of contraction and expansion of tooth structure and restorative material?

Microleakage, when the dental material pulls away from the tooth, or a faulty restoration. This separation of material and tooth could allow fluids, debris, and microorganisms to enter between the restoration and the wall of a cavity preparation.

Microleakage

Microscopic space located at the interface of the tooth structure and the sealant or restoration (faulty restoration)

What is the ideal lighting for shade selection?

Natural light. If the dental light is used it should be moved to the side of the patient to decrease the intensity.

Are either of these two concerns valid, why or why not?

No because when mercury is combined with other materials in dental amalgam, its chemical nature changes so that it is essentially harmless. In addition, the amount released in the mouth under the pressure of chewing and grinding is extremely small and presents no cause for alarm. In fact, this amount is less than what patients are routinely exposed to in food, air, and water.

What are the four major components of dental resins?

Organic resin matrix Inorganic fillers Coupling agent Tooth colored pigments.

Tensile stress and strain pulls

Pulls and stretches the materials. Example: Tug-of-war

What materials are used as the inorganic fillers in composite resins?

Quartz Glass Silica particles Colorants.

Sealant composite

Resembles flowable composites but have the viscosity to allow the material to flow into the pits and fissures of the tooth surface.

BIS-GMA is the foundation of?

Resins

What term describes the ability to hold two things together when they will not adhere to each other?

Retention.

What conditions allow these electrical currents?

Saliva contains salt which makes it a good conductor of electricity. Two metallic components of different composition can act as a battery, and galvanic action, or shock, is the coming together of all these conditions.

Auto-cured

Self-cured materials harden as the result of a chemical reaction of the materials when mixed together

What are the components of the alloy powder?

Silver Tin Copper Zinc

What are the most common dental restorative materials?

Silver amalgam, composite resin, glass ionomer, temporary restorative materials, tooth-whitening products, gold alloy, and ceramic castings.

What term describes the degree to which a substance will dissolve in a given amount of another substance?

Solubility.

Dual-cured

Some curing takes place as the material is mixed. The final cure does not occur until the material has been exposed to a curing light

What are the particle shapes of high-copper alloys?

Spherical (round particles) or Irregular (rough, lathe-cut particles)

What material has been added to the metal reinforced glass ionomer to produce a strong, abrasion-resistant dental material?

Spherical silver-tin alloy.

Copper.

Strength and corrosion resistance

Hardness is an indication of?

Strength and wear-ability

What is the function of the coupling agent in composite resins?

Strengthens the resin by chemically bonding the filler to the resin matrix.

What type of reaction does a dental material undergo when distortion occurs?

Stress

Flowable composite

Supplied as a hybrid or nanofilled composite with enough filler included to make the material wear resistant. Flow is the key term in describing this type of composite. Designed to flow easily.

Zinc.

Suppress oxidation

Describe the following three types of stress and strain:

Tensile stress and strain pulls Compressive stress and strain Shear stress and strain

What organization ensures that standards and strict specifications are followed by dental material manufacturing companies when developing new dental materials?

The Council on Dental Materials, Instruments, and Equipment, which is a subcommittee of the American Dental Association or ADA.

Although each composite kit may contain its own shade guide, what is the universally accepted shade guide?

The VITA Shade Guide.

Wetting.

The ability of a liquid to flow over the surface and come into contact with the small irregularities that may be present. Example: Water has a high wetting ability because it flows easily

Malleability.

The ability of a material (usually metal), to withstand permanent deformation under compressive stress without sustaining permanent damage

List the differences in the technique between an amalgam restoration and a composite restoration.

The cavity preparation for a composite resin is designed to hold the resin material by means of a bonding system rather than by retention added into the preparation Some dental materials cannot be used with composite resins The matrix system will vary with composite resins Placement of composite resin is accomplished in increments in which light-curing is performed before additional increments are added.

How is ceramic used in dentistry?

The ceramic material is adhered to a metal casting, creating the "best of both worlds" in strength and esthetics.

What does the exact curing time of light-cured resins depend on?

The composite manufacturer's instructions, most often 20 to 60 seconds; thickness and size of the restoration, when larger quantities are being placed, each increment is cured before the next is placed; and the shade of the restorative material used, the darker the shade, the longer the required curing time.

What does a clinical dental assistant need to understand about materials?

The general characteristics of each type of dental material, the selection criteria, and ways to prepare the restorative and esthetic materials for a procedure.

What material is used most often as a short-term restoration that is placed in a tooth to last for a short time?

The intermediate restorative material, or IRM, which is a reinforced zinc oxide-eugenol composition.

What does an understanding of dental materials provide the dental assistant?

The knowledge necessary to recognize the types of procedures practiced by the general dentist.

What will determine the type of temporary restorative material selected?

The location and the amount of tooth structure that needs to be restored.

What steps are followed once the amalgam has been triturated?

The mixed mass is placed from the capsule into an amalgam well, the pestle is removed and placed back into the capsule, and the mix is loaded back into the amalgam carrier.

What is amalgamation, or trituration?

The process by which mercury and alloy powders are mixed together to form the mass of amalgam needed to restore the tooth.

Percolation

The process of a liquid substance passing through a porous substance

Viscosity.

The property of a liquid that causes it not to flow easily. Example: Maple Syrup

What is the most unique quality about glass ionomer?

The release of fluoride after the final setting which provides the added advantage of inhibiting decay around a restoration.

What do the particle shapes influence?

The trituration and working characteristics (condensing and carving) of the resulting amalgam mixture.

What is the function of the fillers?

To add the strength and other characteristics that are needed in a restorative material. The ability of these materials to reflect light facilitates the creation of an esthetically pleasing restoration.

What is the purpose of activating the capsule before trituration?

To break the seperating membrane.

What is the general use of temporary restorations?

To maintain and restore function and keep the patient comfortable for a limited period of time.

What is the purpose of condensing each increment of amalgam?

To pack the amalgam tightly into all areas of the prepared cavity and to aid in removing any excess mercury from the amalgam mix.

Restorative.

To restore or bring back to it's natural appearance

What is one of the fastest and most cost-effective ways of restoring the esthetic appearance of teeth?

Tooth whitening, also referred to as bleaching.

What may be the toxic effects of an increase in exposure of mercury vapors for dental personnel?

Tremors, kidney dysfunction, depression, and central nervous system disorders.

Compressive stress and strain

Two forces directed toward each other Example: Chewing

Shear stress and strain

Two forces of material parallel to each other sliding in opposite directions Example: Cutting paper with scissors

Describe the use of hard, type III, gold alloys.

Used for inlays, full crowns, three-quarter crowns, and anterior or posterior bridge abutments.

Describe the use of medium, type II, gold alloys.

Used for almost all types of cast inlays and posterior bridge abutments.

Describe the use of soft, type I, gold alloys.

Used for casting inlays subject to slight stress during mastication.

Describe the use of extra hard, type IV, gold alloys.

Used for crowns, bridges, and cast-removable partial dentures.

Hybrid composite

Used most often today. Are cured with a visible light-curing method and can be polished smoother than macrofilled composites, yet they have greater strength than is seen with microfilled composites. High wear resistance and excellent shading characteristics.

Describe the light-curing process.

Uses a high-intensity blue light source that provides an effective curing of resins. The blue light source is a combination of tungsten and halogen lighting.

What is included in the composite resin "kit"?

Varying shades of the composite resins, along with an etching and bonding system that works specifically for the application process of that material.

In what situations is amalgam contraindicated?

When esthetics is particularly important, such as in the anterior teeth or in facial surfaces that can be viewed; with patients who have a history of allergy to mercury or other amalgam components, and when a large restoration is needed and the cost of other restorative materials is not a significant factor in the treatment decision.

When were macrofilled composites used?

When greater strength was required to resist fracture for class I and II restorations.

Contraction and Expansion.

When temperature changes occur, each type of dental material will contract or expand at its own rate. It is essential that the tooth structure and restorative material have the same rate of contraction and expansion.

Why is adhesion between the dental material and the tooth structure a major concern?

Without proper adhesion, microleakage can occur and the restoration could come out.

Tin.

Workability and strength

Can a provisional restoration be placed by an expanded function dental assistant?

Yes, in most states because it is not considered permanent.

Can an intermediate restoration be placed by an expanded function dental assistant?

Yes, in most states.