Class 1 Cavity Preparation Flashcards

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Questions and Answers

What are pits and fissures cavities?

All the cavities on the occlusal surfaces and the occlusal 2/3rds of the facial and lingual surfaces of the posterior teeth and the lingual surfaces of maxillary incisors.

What is enamel composed of?

Millions of enamel rods or prisms.

Where do the enamel rods exist?

Extend from the DEJ to the external surface of the tooth.

What is the direction of the enamel rods?

Perpendicularly oriented to both the DEJ and tooth surface. Signup and view all the answers

How does the direction of the enamel rods differ in the cervical region?

Enamel rods are oriented apically. Signup and view all the answers

What are the US public health criteria for describing a carious lesion?

Opacity surrounding the pits and fissures, softening of the base of pits and fissures, softened enamel that may flake away by the explorer, stickiness, loss of normal translucency of enamel. Signup and view all the answers

What are cavities that extend beyond frank cavity into the dentin?

Extensive cavities. Signup and view all the answers

What is a prepared cavity?

Cavity prepared because of a carious lesion and it is ready for insertion of restorative materials. Signup and view all the answers

What does the external outline principle: CSM state?

All cavosurface margins must be placed 0.5mm beyond defective tissue in the sound tooth structure. Signup and view all the answers

What is meant by extension for prevention?

Do not exceed 0.5 mm beyond defective tissue. Signup and view all the answers

What are the external outline characteristics?

Extent of carious lesion, removal of other enamel defects, convenience: access, visibility, relation with adjacent and opposing teeth, soft tissue consideration and esthetics. Signup and view all the answers

How do you decide on the extent of external outline in the clinic?

Before the start of cavity preparation: use explorer to identify starting locations and remove fissure or caries where microleakage may be occurring. Signup and view all the answers

What is enameloplasty?

Reshaping the saucer shape of enamel surface with a bur if 1/3 or less of enamel depth is involved. Signup and view all the answers

Describe pulpal line angles.

Round and defined. Signup and view all the answers

Describe mesial and distal walls.

Should make obtuse angles with pulpal floor. Signup and view all the answers

What are the pros and cons of Dr. Sturdevant preparation?

Pro: Retentive restoration, strong restoration margin; Con: May leave unsupported enamel rods. Signup and view all the answers

What are the pros and cons of Dr. Charbeneau preparation?

Pro: No unsupported enamel rods; Con: Less retentive restoration, restoration with weaker margin, needs extra dentinal retention. Signup and view all the answers

What are the pros and cons of Dr. Hadavi preparation?

Pro: No chance to leave behind unsupported enamel rods; Con: Moderately retentive restoration, restoration with moderately strong margin. Signup and view all the answers

What is Dr. Sturdevant amalgam margin?

90 degrees. Signup and view all the answers

What is Dr. Charbeneau amalgam margin?

Acute angle. Signup and view all the answers

What is Dr. Hadavi amalgam margin?

Larger but still acute angle. Signup and view all the answers

Why do mesial and distal walls diverge pulpo-occlusally?

To be parallel to the enamel rods, to preserve intact dentin, for stronger marginal ridges. Signup and view all the answers

What are the general principles in establishing outline form?

Remove carious lesion completely, place margins in sound enamel, remove all undermined enamel rods. Signup and view all the answers

What is the desired degree of smoothness or roughness for enamel walls based on the restorative materials used?

Smooth wall for cast gold restoration; rough walls for composite restoration; acceptable walls for amalgam restoration. Signup and view all the answers

What is convenience form?

Shape or form that a cavity takes to facilitate adequate visibility and accessibility. Signup and view all the answers

What are the tooth preparation principles for amalgam?

Caries are removed, weakened tooth structure is removed, remaining tooth structure is left as strong as possible, underlying pulpal tissue is protected, restorative material is retained in a strong, esthetic, and functional manner. Signup and view all the answers

What are the tooth preparation principles for modified preparation, composite and bonding?

Non-uniform depth, more shallow, preparation of walls of varying height or width, marginal angles of 90 degrees or greater, more enamel bevels and less (or no) need for retention and resistance forms. Signup and view all the answers

What should an examination kit contain?

Mouth mirror, explorer, calibrated condenser, cotton pliers. Signup and view all the answers

What are cavity preparation instruments?

Rotary cutting instruments: 256, high and low speed; hand cutting instruments: chisel: 15-8-12; hatchet: 15-8-14; hoe. Signup and view all the answers

What are the steps in cavity preparation?

Penetration, extension, finishing cavity. Signup and view all the answers

What is the proper bur direction for preparing an occlusal cavity?

A bur should be placed 90 degrees on the plane that passes over the cusps and the marginal ridges. Signup and view all the answers

What should the cavity outline and walls have?

Smooth curves and straight lines. Signup and view all the answers

What does the design of the cavo-surface angle depend upon?

The restorative material being used: amalgam: butt joint margin; composite or cast gold: bevel margin. Signup and view all the answers

How should internal outline be defined?

Defined and round but not sharp. Signup and view all the answers

What are some popular mistakes in cavity preparation?

Unsupported rods, under-extended cavity, not removing caries completely, shallow or too deep cavities, malshaped internal outline, under/over-extended external outline. Signup and view all the answers

Study Notes

Cavity Preparation Overview

Pits and fissures cavities are located on occlusal surfaces and occlusal 2/3rds of facial and lingual surfaces of posterior teeth, as well as the lingual surfaces of maxillary incisors.
Enamel comprises millions of enamel rods or prisms that extend from the dentino-enamel junction (DEJ) to the tooth's external surface.
Enamel rods are oriented perpendicularly to both the DEJ and the tooth surface, with a deviation to an apical direction in the cervical region.

Carious Lesion Identification

US public health criteria for carious lesions include opacity around pits and fissures, a soft base, softened enamel that flakes, stickiness, and loss of translucency.
Extensive cavities are those that extend beyond frank cavities into dentin, indicating deeper carious involvement.

Cavity Preparation Definitions

A prepared cavity is one that has been readied for the insertion of restorative materials after a carious lesion has been addressed.
The external outline principle requires that all cavosurface margins extend 0.5 mm beyond any defective tissue into sound tooth structure.

External Outline Considerations

Characteristics of the external outline include the extent of caries, removal of surrounding enamel defects, convenience of access and visibility, and considerations of soft tissue and aesthetics.
To determine external outline extent, begin cavity preparation with an explorer to locate starting points, and remove fissures or caries contributing to microleakage.

Enamel Reshaping and Angles

Enameloplasty reshapes the enamel surface and may be performed if only 1/3 or less of the enamel depth is affected.
Pulpal line angles should be rounded and well-defined, while mesial and distal walls must create obtuse angles with the pulpal floor.

Restoration Techniques Overview

Dr. Sturdevant's preparation encourages a retentive restoration but may leave unsupported enamel rods.
Dr. Charbeneau's method avoids unsupported rods but results in weaker margins needing additional dentinal retention.
Dr. Hadavi’s approach also avoids unsupported rods but maintains moderate restoration strength.

Amalgam Margins

Sturdevant's amalgam margins are characterized by a 90-degree angle, while Charbeneau's typically form an acute angle, and Hadavi's are larger but still acute.

Cavity Wall Characteristics

Mesial and distal walls diverge pulpo-occlusally to align with enamel rods, preserve intact dentin, and strengthen marginal ridges.
General principles for establishing outline form include complete removal of carious lesions, placement of margins in sound enamel, and elimination of undermined enamel rods.

Wall Smoothness and Roughness

For smooth walls, cast gold restorations permit undistorted impressions and close adaptation.
Rough walls, often found in composite restorations, enhance bonding surface area.
Acceptable walls in amalgam restorations aid in reducing marginal leakage.

Tooth Preparation Principles

For amalgam, all carious and weakened structures are removed, leaving strong tooth structure, while protecting underlying pulpal tissue.
Modified preparation for composite emphasizes non-uniform depth, varying wall heights, and bevels.

Examination and Instrumentation

An examination kit for cavity preparation should include a mouth mirror, explorer, calibrated condenser, and cotton pliers.
Cavity preparation instruments encompass rotary cutting tools (256, high and low speed) and hand cutting tools (chisels, hatchets, hoes).

Preparation Steps and Guidelines

The steps in cavity preparation are penetration, extension, and finishing.
A bur for occlusal cavity preparation should be placed at 90 degrees to the plane over the cusps and marginal ridges.
Cavity outlines should feature smooth curves and straight lines, adhering to specific angles based on restorative materials.

Internal Outline Qualities

The internal outline of a cavity should be defined and rounded but not sharp.
Common preparation mistakes include unsupported enamel rods, under/over-extension, and non-conformity to tooth anatomy.

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Description

Test your knowledge on cavity preparation with these flashcards designed for Class 1 students. Learn about pits and fissures, the composition of enamel, and the structure of enamel rods. Perfect for reinforcing dental terminology and concepts essential for future practice.