سنية 2 محاضرة الwaxes
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Questions and Answers

Self cure is also known as chemical cure.

True (A)

A higher melting range is required for direct wax patterns compared to lab patterns.

True (A)

Sticky wax remains flexible when heated.

False (B)

Pattern waxes must have low flow at working temperatures to prevent distortion.

<p>True (A)</p> Signup and view all the answers

Corrective impression wax is made from paraffin and hydrocarbon wax.

<p>True (A)</p> Signup and view all the answers

Bite registration wax is not susceptible to distortion during removal.

<p>False (B)</p> Signup and view all the answers

The flow of bite registration wax at 37°C is between 2.5% and 25%.

<p>True (A)</p> Signup and view all the answers

If the melting temperature of wax is too high, it becomes easier to work with.

<p>False (B)</p> Signup and view all the answers

Boxing and utility wax is soft and easily shaped.

<p>True (A)</p> Signup and view all the answers

Burn out without residue is an important property of pattern waxes.

<p>True (A)</p> Signup and view all the answers

Waxes are commonly used in the final dental restoration.

<p>False (B)</p> Signup and view all the answers

Beeswax was historically used for creating patterns in dentistry.

<p>True (A)</p> Signup and view all the answers

The lost wax technique involves removing wax patterns by melting or burning them.

<p>True (A)</p> Signup and view all the answers

Waxes have only organic components, with no synthetic materials used.

<p>False (B)</p> Signup and view all the answers

The physical properties of waxes are governed by ANSI-ADA spec.4.

<p>True (A)</p> Signup and view all the answers

Paraffin is a type of natural wax used in dentistry.

<p>False (B)</p> Signup and view all the answers

Residual stress in wax patterns can adversely affect the quality of final restorations.

<p>True (A)</p> Signup and view all the answers

Boxing waxes are categorized under processing waxes.

<p>True (A)</p> Signup and view all the answers

Inlay wax is composed of five or six components including paraffin and carnauba.

<p>True (A)</p> Signup and view all the answers

The melting range for inlay wax indicates the temperature at which it transitions from solid to liquid.

<p>True (A)</p> Signup and view all the answers

Heat treatment of the carver is a method to increase residual stress in wax patterns.

<p>False (B)</p> Signup and view all the answers

The dimensions of baseplate wax are 15 cm long, 7.5 cm wide, and 0.13 mm thick.

<p>False (B)</p> Signup and view all the answers

Inlay wax can be used in both mouth and laboratory temperatures.

<p>True (A)</p> Signup and view all the answers

Casting wax has a slight tackiness to it.

<p>True (A)</p> Signup and view all the answers

Baseplate wax is only available in one type regardless of temperature.

<p>False (B)</p> Signup and view all the answers

Inlay wax measures 6 cm wide and 7.5 cm long.

<p>False (B)</p> Signup and view all the answers

Fluctuation related to water requires investment within 30 minutes.

<p>True (A)</p> Signup and view all the answers

There are no soft types of baseplate wax available.

<p>False (B)</p> Signup and view all the answers

Dr. Thurra Abbas documented the wax specifications on 11/17/2024.

<p>True (A)</p> Signup and view all the answers

The casting wax is designed to be completely non-tacky.

<p>False (B)</p> Signup and view all the answers

Flashcards

Waxing

A crucial step in dental laboratory work where wax models are created to match the final restoration's shape and size. These wax patterns can then be used to create various dental restorations like inlays, crowns, and prosthesis.

Lost Wax Technique

This technique involves creating a wax pattern of the desired restoration, surrounding it with investment material, and then melting the wax to leave behind a mold. This mold is then used to cast the final restoration, often made of metal or ceramic.

Beeswax

A key ingredient in waxes used in dentistry, often derived from bees.

Melting Range

The temperature range at which a wax melts, from the point where it starts to soften to the point where it becomes completely liquid.

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Excess Residue

The amount of residue that remains after wax is burned or melted out of the mold during the lost wax technique.

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Flow

The ease with which a wax can flow when heated, allowing it to conform to the desired shape.

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Thermal Expansion

The tendency of wax to expand or contract in size when subjected to changes in temperature.

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Residual Stress

The internal stresses that can exist within a wax pattern, which can affect the final restoration.

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Inlay Wax

A type of wax used to create patterns for inlays in the lost wax technique.

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Processing Waxes

Waxes used to hold or support other wax components, as well as to create a mold for the final restoration.

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Baseplate Wax

A specific type of wax designed for creating temporary dental casts or models, used for making impressions and guiding bite registration.

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Inlay Wax Composition

A blend of ingredients, often including paraffin, beeswax, carnauba wax, and cresin. Each component contributes to the wax's characteristics, like hardness and melting point.

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Casting Wax Tackiness

A property of inlay wax designed to allow for a temporary hold onto the prepared tooth during the impression-taking process.

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Inlay Wax Temperature Flexibility

Inlay wax is designed to work effectively at various temperatures, allowing for adaptability during different stages of the dental process.

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Baseplate Wax Types

Baseplate wax exists in different types (soft, medium, and hard) depending on the intended use and required flexibility.

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Inlay Wax Dimensions

Inlay wax is typically 7.5 cm in length and 6 mm in width, with 3 primary components working together to create a strong and durable dental restoration.

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Baseplate Wax Dimensions

Baseplate wax is typically 7.5 cm in width, 15 cm in length, and 0.13 mm thick.

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Inlay Wax Refinement

The process of shaping, manipulating, and refining the detail of the inlay wax to ensure a perfect fit during the impression-taking process.

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Pattern Waxes

A category of dental materials that are used to create temporary impressions, models, and bite registrations. It's essential for creating accurate representations of teeth and jaw alignment.

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Self-cure resins

Used for creating patterns for dental restorations, they solidify through a chemical reaction.

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Light-cure resins

Harden when exposed to specific wavelengths of light, often blue light.

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Composite resins

A type of resin, often used for fillings, which combines both resin and filler particles.

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Low flow in working temperature

The quality of wax to flow minimally at its working temperature to prevent distorting the pattern.

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Melting range higher than the environment

Ensures the wax model doesn't melt too easily during the process.

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Boxing and utility waxes

Waxes designed for boxing and utility purposes, easy to shape, soft, and available in long strips.

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Sticky wax

This wax gets sticky when heated, but brittle when cold, helpful for assembling metal and gypsum pieces.

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Corrective impression wax

Placed over an original impression, this wax assists in creating a functional impression, made from paraffin and hydrocarbon wax, flows readily at mouth temperature.

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Bite registration wax

Used to capture the bite of a patient, it flows readily at 37° Celsius, but is prone to distortion upon removal.

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Replacement of bite registration wax

Materials like addition silicones and polyethers have widely replaced bite registration wax due to their improved properties.

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Study Notes

Waxes in Dentistry

  • Waxes are used in various aspects of dentistry, both in clinics and labs.
  • They aren't used in final restorations, but are crucial for fabricating and ensuring successful metal or ceramic restorations.
  • Beeswax was utilized for patterns 200 years ago.
  • Waxing is a lab procedure used to create wax models that precisely match the final restoration's form and dimensions.
  • Types of wax models include fillings and crowns; also, prosthetic devices made of vitallium or acrylic.

Lost Wax Technique

  • The lost-wax technique uses a wax pattern to define a space within a stone-like material.
  • This process eliminates the wax pattern, creating a cavity that is then filled with metal.

Requirements of Dental Wax

  • The wax must perfectly match the size, shape, and contour of the intended appliance.
  • It should have sufficient flow when melted to accurately reproduce fine details.
  • No dimensional changes should occur after the wax is formed.
  • The wax should be able to be melted without leaving any residue.
  • The wax should be easily carved to produce a smooth surface.
  • The wax should have distinct color contrast to facilitate proper margin finishing.

Wax Components

  • Waxes can be classified as natural or synthetic.
  • Natural waxes include mineral (like paraffin and ceresin), plant (such as carnauba and candelilla), and animal (like beeswax).
  • Synthetic waxes are used to modify the characteristics of natural waxes, like polyethylene.

Classification of Waxes

  • Mineral waxes are refined from crude oil or petroleum.
    • Paraffin wax has a relatively low melting point (50-70°C) and is brittle.
    • Ceresin wax comes from petroleum and has a medium melting range (60°C).
  • Plant waxes are derived from palm trees, like carnauba, and other plants like candelilla.
    • They are hard, tough, and have a high melting point (80-85°C).
  • Animal waxes are extracted from animal products.
    • Stearin comes from beef fat, and has a low melting point.
    • Beeswax is extracted from honeycombs, partially crystalline natural polyester, and is brittle with a medium melting temperature (60-70°C).

Properties of Waxes

  • Waxes are organic molecules with high molecular weights.
    • The main components are hydrocarbon (paraffin) and high molecular weight esters.
  • Wax properties are regulated by ANSI-ADA specifications.
    • These specifications address melting range, excess residue, flow, thermal expansion, and residual stress.
  • Flow (a change in shape or dimension in response to force) is crucial.
  • Wax patterns placed in casting molds are melted out; residue affects the quality of the restoration.
  • The size of the material (e.g., inlay wax, baseplate wax, casting wax, and resins).
  • The waxes are used in auxiliary roles during the fabrication of models, impressions, and soldering.
  • There are categories of waxes used for different purposes (pattern waxes and processing waxes).
  • Examples are Inlay wax, casting wax, baseplate wax, boxing wax, utility wax, and sticky wax.
  • Specific wax types have different components, sizes, and melting point ranges depending on function.

Minimizing Residual Stress in Wax

  • Minimize this by controlling heating during the carving process, using small increments, maintaining consistent temperature, quick investments, and refining crucial details.
  • Controlling the heating to appropriate temperatures.
  • Preventing environmental temperature fluctuations, by using isolation.

Important Properties of Pattern Waxes

  • Low flow in working temperatures prevents distortion of the wax pattern.
  • The melting range should be higher than the environment; laboratory patterns have lower melting points than directly made wax patterns.
  • Excess heat can make the wax difficult to work with.
  • Complete burning away without any residue is important.

Types of Waxes

  • Pattern waxes are used to create models of restorations, including inlay, casting, and baseplate waxes.
  • Processing waxes aid in accessory phases of model production, impressions, and soldering.
  • Examples of processing waxes are boxing, utility, and sticky waxes.
  • Resins have recently been used for pattern and processing materials.

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