Capter 43

Dental Materials

Mechanical Properties

Properties that determine how a dentsal material withstands forces in the mouth.

Force

Any puch or pull on matter

Strain

Result of stress. Change/deformation of material

Tensile stress

stress that pulls or stretches material

Compressive stress

stress that pushes material together

Shear stress

stress caused by two parallel forces in opp directions

Malleability

Ability of a metal to be extended in all directions by a compressive force

Ductility

Ability of a metal to be stretched or drawn out by pulling or tensile force without breaking

Thermal change

Change in temp by hot or cold products

Micro leakage

space that develops allowing saliva and bacteria to enter.

Percolation

liquid slowly passing through pores

Ideal THermal Expansion

restorative material should expand and contract at simular rate to the tooth

Galvanic shock

tingling casused by galvanic action

galvanic action

electrial current produces whern two differnt meltads are present.

Corrosion

reaction whne metal is exposed to temp, humidity, saliva

hardness

materials resistanceto indentation, scratch and abrasion

Solubility

THe degree which a substance will dissoce in an amount of time.

Flow

Ability of a dental material; to reai pliable to flow into a tooth

Adhesion

Strength the causes materials to adhere or stick together

Wetting

liquid's ability to spread out and stick to a solid surface instead of beading up.

Viscosity

Property of thick fluids

Retention

Holding two things together

Mechanical Retention

retention by creating a physical desing or structure (pins)

Chemical Retention

Retencion through chemical bonding (glue)

Curing

Setting and hardening process of a dental material caused byu chemical reaction or light.

light curing

Material that hardens after exposure to a curing light

auto cureing

material that hardens becuasse of a chemical reaction after the compenents are mixed

Dual cured

Material which has some curing occur during mixing, and is finally cured after exposer to light

Direct Restorative Material

Material places directly into tooth while it is pliable and can be adapted and carved

Indirect Restorative Material

Made outside of mouth, usually by dental lab tech.

Amalgam

restorative material, made of alloy powder with mercury. used for back teeth

Silver in amalgam provides

strenth

Tin in amalgam

provides workability and stenth

Copper in Amalgam

strength and corrosion resistant

Zinc in Amalgam

supresses oxidation

Eames technique

amalgam mixing technique usijng 1 to 1 ratio of mercury to alloy.

Trituration

Process of mixigng mercuiry and alloy together ( amalgamation)

Under-triturated amalgam

not been mixed enought.

Over-triturated amalgam

mixed too much

Condensation

packing amalgam tight in all areas of cavity and also helps remove acess mercury.

Amalgam carrier

instrumetn used to carry amalgam into tooth

amalgam condeser

instrument used to pack amalgam into place

Amalgam carving

carving amalgam to tooth natural anatomy

Burnisher

instrument used to smooth amalgam

Articualting paper

used to check the occlusion of newly placed restoration

Amagam indications

stress bearing areas, small to mod posterior cavities, severe destruction of tooth structure , foundations for certain restorations, poor oral hygiene, cost, moisture control in mouth.

Amalgam Contraindications

Esthetic concerns, allergy to mercury/amalgam components, or situations where a large restoration is needed and cost is not a significant concern.

Composite Resin

A tooth-colored restorative material widely used because of its esthetic qualities.Composite Resin Components

Composite Resin Components

- Organic resin matrix, inorganic fillers, coupling agent, and pigments.

Organic Resin Matrix

The organic portion of composite resin that contains carbon.

Inorganic Fillers

Materials added to composite resin to provide strength and other physical/chemical characteristics.

Coupling Agent

Chemically bonds the inorganic filler to the organic resin matrix.

Pigments

Components that provide composite resin with its color.

Flowable Composite

A composite material designed to flow more easily.

Sealant Composite

A low-viscosity composite designed to flow into pits and fissures.

Composite Resin Indications

Class I, II, III, IV, and V restorations; surface defects; closing diastemas; and esthetic recontouring.

Composite Resin Unfavorable Conditions

Poor isolation, poor oral hygiene, severe bruxism, or lack of a night guard.

Composite Resin vs. Amalgam

Composite is more esthetic and commonly light-cured, but is more technique-sensitive and generally less strong than amalgam

Composite Increment Size

Typically 1–2 mm increments should be placed and light-cured at one time.

Composite Shade Timing

Shade should be selected before tooth preparation because dehydration/desiccation can change the tooth's color.

Shade Lighting

Tooth shade should ideally be determined in daylight or standardized daylight lighting

Polymerization

The process by which resin changes from a pliable state into a hardened restoration.

Composite Finishing

Finishing burs and abrasive materials are used because completely hardened composite cannot be carved like amalgam.

Glass Ionomer

A versatile dental material that chemically adheres to teeth and releases fluoride after setting.

Major Advantage of Glass Ionomer

It chemically adheres to tooth structure and releases fluoride.

Glass Ionomer Indications

Primary teeth, nonstress areas such as Class V and root surfaces, sealants, core buildup material, and provisional restorations.

Glass Ionomer Composition

A combination of glass, ceramic particles, and a glassy matrix.

Temporary Restoration

A restoration designed to maintain function, protect the tooth, and keep the patient comfortable for a limited period.

Temporary Restoration Uses

Reduce sensitivity, maintain function/esthetics until a permanent restoration, protect prepared-tooth margins, and prevent movement of adjacent/opposing teeth.

Intracoronal Restoration

A restoration in which the material is surrounded by tooth structure.

Extracoronal Restoration

A restoration in which the restorative material extends over a cusp.

IRM

Intermediate Restorative Material; a reinforced zinc-oxide eugenol material.

Eugenol

Component of IRM that has a sedative effect on the pulp.

IRM Uses

Primary teeth, restorative emergencies, caries management, and temporary treatment of sensitive teeth.

IRM Compatibility with Composite

IRM is not compatible with composite resin.

IRM Powder-to-Liquid Ratio

One drop of liquid to one scoop of powder when mixed manually.

Provisional Restorative Material

Material designed to cover a major portion of a tooth or several teeth for a longer period.

Exothermic Reaction

A reaction that gives off heat.

Tooth Whitening

An esthetic procedure used to improve the appearance of discolored teeth.

Whitening Materials

Most tooth-whitening products contain a peroxide-based ingredient.

Peroxide

Whitening ingredient that works within enamel to remove staining and discoloration.

Natural Tooth Whitening

Only natural tooth structure will whiten; direct composite and indirect porcelain restorations will not.

Causes of Tooth Discoloration

Aging, coffee/tea/cola/tobacco, trauma, tetracycline, excessive fluoride, nerve degeneration, and aging restorations

Tooth Whitening Contraindication

Whitening is contraindicated during pregnancy and lactation.

Carbamide Peroxide

Common bleaching ingredient in whitening gels; the presentation states typical gel concentrations of 10–30%.

At-Home Whitening

Generally uses lower concentrations than in-office whitening.

Indirect Restoration Indications

Significant loss of tooth structure, trauma, decay, fracture, endodontically treated teeth, cosmetic/function needs, or restoration of an implant.

Gold-Noble Metal Alloy

An alloy combining gold with other metals to provide the hardness and characteristics needed for cast dental restorations.

Pure gold

too soft

Type I Gold alloy

soft alloy used for light stress

Type II Gold Alloy

Medium alloy used for most cast inlays and posterior bridge abutments.

Type III Gold Alloy

Hard alloy used for inlays, full crowns, three-quarter crowns, and anterior/posterior bridge abutments.

Type IV Gold Alloy

Extra-hard alloy designed for crowns, bridges, and cast-removable partial denture frameworks.

Porcelain

A ceramic material used extensively in dentistry because it combines strength, translucency, and natural tooth-color matching.

Ceramics

Compounds consisting of combinations of metallic and nonmetallic elements.

PFM

Porcelain fused to metal.

PBM

Porcelain bonded to metal.

Advantages of Porcelain

Good tooth-color matching, improved anterior esthetics, strength, good insulation, and a low coefficient of thermal expansion.

Porcelain Shade Selection

Ideally performed in natural light, especially for esthetically important areas.

High Coefficient of Thermal Expansion

Can cause problems when the restorative material expands and contracts at a different rate from the tooth or another material.