Boards - Dental Materials

Adhesion

The chemical attraction between unlike molecules

Cohesion

The chemical attraction between like molecules

Coefficient of thermal expansion

An index which indicates how one material reacts to temperature extremes in relation to another

Compressive Strength

The force at which a material breaks under pressure

Creep

Slow dimensional change caused by compression

Ductility

The ability to undergo change of form without breaking

Elasticity

A material's ability to recover its initial shape after undergoing a force

Galvanism

An electrical current generated by dissimilar metals in an acidic environment

Gelation

The process of gelling (solidification by cold)

Imbibition

Absorption of a solvent by gel

Malleability

A material's capacity to be shaped by force or pressure

Microleakage (percolation)

Passage of oral fluids/bacteria into and out of tooth structure due to marginal gap or failure of marginal (restorative) seal

Polymerization

The linking, branching, or cross linking of smaller molecules

Proportional limit

The force at which a material cannot return to its original shape

Syneresis

Contraction of a gel due to the loss of a solvent

Tensile Strength

The force needed to stretch a material to the point of fracture

Viscosity

Resistance to flow

Amalgam

alloy of mercury containing silver, copper, tin and zinc

Bonding Agents

establishes micro mechanical retention with enamel and dentin by adapting to relief areas created by conditioning with phosphoric acid; example: BIS-GMA

Sealants

Barrier used to protect the occlusal surfaces of teeth from bacterial assault by sealing anatomically unprotected tooth structure with resin

Composite

An esthetic restorative material composed of a bonding agent and tooth colored filler particles of various sizes; usually silicates, quartz or glass

Liners

Used to seal dentin or medicate the dental pulp; Includes Calcium hydroxide, Zinc oxide/eugenol, and resin modified glass ionomer

Bases

Used to provide thermal insulation or mechanical protection for the dental pulp; Includes all cements due to poor thermal conductors and adequate compressive strength

Cements

Used to affix a restoration to tooth structure as a base; includes zinc phosphate, polycarboxylate, and glass ionomer

Zinc phosphate Cement

exothermic reaction on mixing; mechanical interlock between tooth and casting

Polycarboxylate Cement

High chemical affinity for enamel; powder mixed with polyacrylic acid

Glass Ionomer Cement

Releases fluoride, binds to dentin, coefficient of thermal expansion approximates tooth structure, can be used as a class V restorative material

Resin Cement

Tooth colored cement to affix esthetic restorations like porcelain laminate veneers and tooth colored inlays, onlays, or crowns, ad clear orthodontic brackets; Used for luting etched metal retainers such as resin bonded bridges and prefabricated endodonti

Hybrid Cements

Resin modified glass ionomers, seals dentin effectively to minimize sensitivity, releases fluoride (glass ionomer)

Zinc-oxide/eugenol cement

used for temporary cementation, temporary aluminum shell crown, orange solvent used to clean insruments

Rigid (Inelastic) Materials

plaster, Type I Gypsum, compound, and zinc oxide/eugenol

Reversible Hydrocolloid

Aqueous (water soluble) material that undergoes a physical reaction, temperature dependent, gelation from cold, unstable, susceptible to imbibition and syneresis; Ex: Agar

Irreversible Hydrocolloid

Aqueous material that undergoes a chemical reaction, not temperature dependent but setting can be delayed by cold or accelerated by warm water; unstable, susceptible to imbibition and syneresis; Es: Alginate

Non-aqueous Materials

Polysulfide rubber, polyether rubber, silicone rubber, vinylpolysiloxane

Gypsum Products

Mineral, Calcium, Sulfate, di-hydate; heated to refine material; includes alpha and beta calcium sulfate hemi-hydrate

Inlay and Casting Wax

used for cast restorative patterns

Baseplate Wax

useful in removable prosthetic procedures

Bite registration Wax

useful to obtain occlusal records

Boxing Wax

used in pouring models

Sticky Wax

Becomes sticky when heated, used to attach models

Utility Wax

used to modify the shape of impression trays and cushion braces

Casting Alloys

Used to fabricate inalys, onlays, crowns, and bridges; can be precious or non precious alloys

Precious Alloys

contains noble metals that can resist tarnish and corrosion; includes gold, platinum and palladium

Nonprecious Alloys

contains base metals which are subject to tarnish and corrosion; may be allergenic, includes silver, copper, nickel, tin and zinc

Implants

Biocompatible titanium alloy prosthesis used to replace missing teeth; endosteal (within bone); leading cause of failure is mobility

Tartar Control Active Ingredient

Pyrophosphate

Gum Care Tooth Paste Ingredient

Triclosan (antimicrobial agent)

Desensitization Tooth Paste Ingredient

Potassium Nitrate, Sodium Citrate, Strontium Chloride

Vital Bleach Ingredient

Carbamide Peroxide or hydrogen peroxide