Wax Pattern in Dental Casting

Questions and Answers

Which technique is primarily used in the case of intra-coronal restorations?

Indirect technique

Indirect-direct technique

Direct technique (correct)

Dipping method

The dipping method results in a thick layer of wax that captures all details of the preparation.

False

What tool is used for measuring the thickness of wax?

Wax caliper

The wax pattern is primarily constructed using __________ techniques.

direct and indirect Signup and view all the answers

Match the method of wax pattern construction with its description:

Dipping method = Creates a thin layer called coping Incremental method = Built using melted wax added incrementally Direct technique = Constructs in the patient's mouth Indirect technique = Uses a prepared die on a stone cast Signup and view all the answers

Which type of wax is used in the indirect technique?

Soft wax Signup and view all the answers

Incremental method does not induce any stresses during construction.

False Signup and view all the answers

What is the main advantage of the indirect technique?

High accessibility and time saving Signup and view all the answers

In coping construction, the thickness of the layer should be approximately __________ mm.

0.3 Signup and view all the answers

What should be done before removing the wax pattern from the die?

Allow it to cool Signup and view all the answers

What is the appropriate contour for axial surfaces of a pattern that allows oral hygiene and accommodates inter-dental papilla?

Straight emergence profile Signup and view all the answers

Contact areas of maxillary teeth should be located centrally.

False Signup and view all the answers

What happens if a margin is over-contoured?

Plaque accumulation and periodontal diseases Signup and view all the answers

The palatal cusps of upper teeth and buccal cusps of lower teeth are referred to as __________ cusps.

functional Signup and view all the answers

Match the following terms with their definitions:

Functional cusps = Used for grinding food Non-functional cusps = Prevent overflowing of food Tripoding = Cusp contact in three points Curve of Spee = Important in protrusive movement Signup and view all the answers

What should be done with the occlusal contacts to avoid wearing?

Contact at the base of triangular ridge Signup and view all the answers

Under-contouring is more significant than over-contouring for causing gingival issues.

False Signup and view all the answers

What is the recommended thickness of the veneering porcelain in a wax pattern for a PFM crown?

0.8-1mm Signup and view all the answers

The process of milling wax blocks using CAD/CAM machines is referred to as __________.

CAD Wax Signup and view all the answers

What is a consequence of an open contact between teeth?

Food wedging leading to caries Signup and view all the answers

What is the first step in the lost wax technique for cast restoration?

Wax pattern is fabricated Signup and view all the answers

Type II wax is used for direct techniques inside the patient's mouth.

False Signup and view all the answers

What is the purpose of adding beeswax in the composition of the wax pattern?

To increase melting temperature and provide rigidity. Signup and view all the answers

The process of burning out the wax pattern creates a ______ for the molten metal to flow into.

mold Signup and view all the answers

Match the type of wax with its characteristic:

Type I = Soft wax used for indirect technique Type II = Medium wax that softens at 37 °C Bees wax = Increases melting temperature Dammer resin = Reduces flakes in the wax pattern Signup and view all the answers

Which of the following is NOT a requirement of casting wax?

Be combustible Signup and view all the answers

The components of a wax pattern include paraffin wax, beeswax, and dammer resin.

True Signup and view all the answers

List two characteristics that casting wax should possess after carving.

Minimum rate of stress relaxation and ability to be carved without chipping. Signup and view all the answers

The heating instrument used for wax pattern fabrication allows for accurate control of ______.

wax temperature Signup and view all the answers

What is the main purpose of using a sprue former in the lost wax technique?

To secure the wax pattern in place Signup and view all the answers

Study Notes

Wax Pattern Overview

The lost wax technique is used to create metal cast restorations from wax patterns.
Process involves: wax pattern > sprue former > investment > burn out of wax > mold > molten metal casting.

Requirements of Casting Wax

Must flow easily and preserve fine details until investment.
Should accept additions and be carved without chipping.
Must be polishable, have minimal stress relaxation, and evaporate without residues.
Different color from die material essential for contrast.
Should retain strength and rigidity after cooling.

Components of Wax Pattern

Paraffin wax or synthetic wax (40-60%).
Beeswax to boost melting temperature and rigidity.
Damar resin included to reduce flaking.
Dies used for color contrast.

Types of Wax

Type I: Medium wax for direct techniques, softens at 37°C.
Type II: Soft wax for indirect techniques, melts at 25°C.

Instruments for Fabrication

Heating instrument (normal or electric) for precise temperature control.
Waxing tools: includes droppers, burnishers, and various carvers.
Wax caliper for measuring thickness.
Zinc stearate powder to assess occlusal contact.

Techniques of Wax Pattern Fabrication

Direct technique allows creation inside the patient's mouth, suitable for intra-coronal restorations using medium wax.
Indirect technique involves preparing a die on a stone cast with soft wax, popular for efficiency.
Indirect-direct technique combines both methods for final adjustments intra-orally.

Methods of Wax Pattern Construction

Dipping method: involves dipping the die into molten wax to create a thin, uniform layer (coping).
Incremental method: wax is melted and added in layers, but frequent additions can induce stress and distortion.

Steps of Wax Pattern Construction

Coping Construction: Thin thimble non-anatomical crown adheres to preparation using dipping or droppers.
Pattern Removal & Evaluation: Cool the wax pattern before removal; ensure accurate adaptation to die.
Proximal Surface: Shape for oral hygiene; specific contact areas differ for maxillary and mandibular teeth.
Buccal & Lingual Surfaces: Height of contour protects gingiva; avoid overcontouring to reduce plaque and gingival issues.
Occlusal Surface: Functional and non-functional cusps defined for grinding and food prevention with tripoding concept.
Margination: Margins refined before investing to improve adaptation, stress relief must be avoided.

Wax Pattern for Veneered Crowns

Full anatomical wax pattern created, with controlled cut-back for uniform veneering porcelain thickness (0.8-1mm) to enhance properties.

Recent Advances

CAD/CAM technology enables milling wax blocks for improved accuracy, documentation, and efficiency in fabrication.

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Description

This quiz covers the process of creating a wax pattern for cast restoration in dentistry using the lost wax technique. It includes steps from the initial wax pattern to the final casting of metal or ceramics. Test your understanding of this essential procedure in dental applications.

Wax Pattern in Dental Casting

Questions and Answers

Which technique is primarily used in the case of intra-coronal restorations?

The dipping method results in a thick layer of wax that captures all details of the preparation.

What tool is used for measuring the thickness of wax?

The wax pattern is primarily constructed using __________ techniques.

Match the method of wax pattern construction with its description:

Which type of wax is used in the indirect technique?

Incremental method does not induce any stresses during construction.

What is the main advantage of the indirect technique?

In coping construction, the thickness of the layer should be approximately __________ mm.

What should be done before removing the wax pattern from the die?

What is the appropriate contour for axial surfaces of a pattern that allows oral hygiene and accommodates inter-dental papilla?

Contact areas of maxillary teeth should be located centrally.

What happens if a margin is over-contoured?

The palatal cusps of upper teeth and buccal cusps of lower teeth are referred to as __________ cusps.

Match the following terms with their definitions:

What should be done with the occlusal contacts to avoid wearing?

Under-contouring is more significant than over-contouring for causing gingival issues.

What is the recommended thickness of the veneering porcelain in a wax pattern for a PFM crown?

The process of milling wax blocks using CAD/CAM machines is referred to as __________.

What is a consequence of an open contact between teeth?

What is the first step in the lost wax technique for cast restoration?

Type II wax is used for direct techniques inside the patient's mouth.

What is the purpose of adding beeswax in the composition of the wax pattern?

The process of burning out the wax pattern creates a ______ for the molten metal to flow into.

Match the type of wax with its characteristic:

Which of the following is NOT a requirement of casting wax?

The components of a wax pattern include paraffin wax, beeswax, and dammer resin.

List two characteristics that casting wax should possess after carving.

The heating instrument used for wax pattern fabrication allows for accurate control of ______.

What is the main purpose of using a sprue former in the lost wax technique?

Study Notes

Wax Pattern Overview

Requirements of Casting Wax

Components of Wax Pattern

Types of Wax

Instruments for Fabrication

Techniques of Wax Pattern Fabrication

Methods of Wax Pattern Construction

Steps of Wax Pattern Construction

Wax Pattern for Veneered Crowns

Recent Advances

Studying That Suits You

Description

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