Class II Cavity Prep Flashcards

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Questions and Answers

What are the steps in the GV Black Cavity Preparation approach? (Select all that apply)

Cleansing the cavity preparation (correct)

Outline form (correct)

Placement of the filling material

Resistance and retention form (correct)

When is the reverse curve more exaggerated?

When the contact is further away from the central groove.

How deep should the pulpal floor be in a Class II preparation?

0.5 mm into dentin.

The bucco-occlusal and linguo-occlusal wall are __ and make a _ angle with the pulpal floor.

parallel, 90 degree Signup and view all the answers

What does the extent of the proximal external outline depend on?

Extent of the carious lesion, breaking the contact with adjacent tooth, convenience to place and finish the restoration. Signup and view all the answers

What is the shape of the proximal external outline?

Triangle. Signup and view all the answers

Why is the proximal external outline a triangle?

Retention, conserve tooth tissue and MR, correspond to the proximal surface morphology and contact. Signup and view all the answers

What is the mandibular bucco-proximal wall angle with gingival floor?

Acute - 80 degrees. Signup and view all the answers

What is the mandibular linguo-proximal wall angle with gingival floor?

Acute - 85 degrees. Signup and view all the answers

What is the maxillary bucco-proximal wall angle with gingival floor?

90 degrees. Signup and view all the answers

What is the maxillary linguo-proximal wall angle with gingival floor?

Acute angle. Signup and view all the answers

What shape should the axial wall be?

Convex. Signup and view all the answers

Bucco and linguo-proximal wall direction (M/D) should make a _____ angle to the tangent of the proximal surface.

90 degree Signup and view all the answers

What is flare?

Divergence of the wall axio-proximally. Signup and view all the answers

What is wrong with excess flare?

There is no unsupported enamel but you lose retention and resistance form. Signup and view all the answers

What is wrong with lack of flare?

Unsupported enamel rods and fracture of tooth structure. Signup and view all the answers

What shape should the gingival floor have?

C shape. Signup and view all the answers

Why should the gingival floor have a C-shape?

So that there is no unsupported enamel. Signup and view all the answers

What determines the width of the gingival floor?

It should be placed 0.5 mm into the dentin, depends on the thickness of the enamel. Signup and view all the answers

What gives the occlusal segment retention?

Dovetail, direction of the buccal and lingual walls pulpo-occlusally, define line angles. Signup and view all the answers

What gives the proximal segment retention?

Triangularity of the box, define line and point angles, 'U' shaped grooves. Signup and view all the answers

Class II cavity preparations can be performed on which teeth? (Select all that apply)

Pre-molars Signup and view all the answers

What hand instruments do you need for a Class II preparation?

Chisel 15-8-12, hatchet 15-8-14, GMT and angle formers. Signup and view all the answers

Why use a wedge?

Depresses interproximal gingiva apically, prevents injury to soft tissue + rubber dam, prevents seepage of saliva and blood through rubber dam, causes minute separation, indicates gingival cavo-surface breakage. Signup and view all the answers

What are three uses for the medial GMT?

Plane the gingiva cavosurface margin of the mesio-proximal box, bevel the mesio-pulpo axial line angle, accentuate or develop retention grooves in disto-proximal box. Signup and view all the answers

What are three uses of the distal GMT?

Plane gingival cam of disto-proximal box, bevel disto-pulpo-axial line angle, accentuate or develop retention grooves in the mesio-proximal box. Signup and view all the answers

What are three burs used in a Class II cavity preparation?

#256 high speed, #256 slow speed, 1/4 round bur. Signup and view all the answers

How are Class II carious lesions diagnosed?

Bitewing radiographs. Signup and view all the answers

On a radiograph, how can you tell the lesion has penetrated the DEJ?

When it appears to have gone 2/3 or more of the way through the enamel into the DEJ. Signup and view all the answers

What determines the occlusal external outline of the proximal box?

The extent of carious lesions and to break contact with the adjacent tooth. Signup and view all the answers

A minimum of ______ of separation should be allowed between the gingival cavo surface and proximal surface of the adjacent tooth.

0.3 mm Signup and view all the answers

Why is the proximal depth at the level of the pulp-axial line angle greater than at the gingival floor area?

Enamel is thicker occlusally than in the gingival region. Signup and view all the answers

Where does the proximal contact point lie on maxillary teeth?

Towards the buccal (reverse curve on buccal and straight on lingual). Signup and view all the answers

What two things does the reverse curve allow?

Preserves the triangular ridge of the cusp, facilitates the formation of a 90 degree angle between proximal walls and the tangent of the proximal surface. Signup and view all the answers

What are four examination instruments?

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

Where is retention in the proximal box placed?

Entirely in dentin. Signup and view all the answers

What does proximal segment retention consist of?

Divergent bucco and linguo proximal walls, defined line and point angles, 'U' shaped groove. Signup and view all the answers

Study Notes

Class II Cavity Preparation Overview

GV Black's approach includes outlining form, resistance and retention form, convenience form, removal of carious lesions, finishing enamel wall, and cleansing the preparation.
The reverse curve is more exaggerated when the contact point is further away from the central groove.
The pulpal floor depth in a Class II preparation should be 0.5mm into dentin.

Wall Angles and Geometry

The bucco-occlusal and linguo-occlusal walls are parallel and make a 90-degree angle with the pulpal floor.
Mandibular bucco-proximal wall angle with the gingival floor is acute at 80 degrees, while the linguo-proximal wall angle is acute at 85 degrees.
Maxillary bucco-proximal wall angle with the gingival floor is 90 degrees, and the linguo-proximal wall angle is acute.

Proximal External Outline

The proximal external outline's shape is triangular, which conserves tooth tissue, provides retention, and matches the morphology of the proximal surface.
The outline extent depends on the carious lesion's size, the need to break contact with adjacent teeth, and convenience for placing and finishing the restoration.

Gingival Floor and Flare

The gingival floor should have a C-shape to prevent unsupported enamel.
The width of the gingival floor is determined by being 0.5mm into dentin, based on enamel thickness.

Retention Features

Retention in the occlusal segment is provided by dovetails, wall direction, and defined line angles.
For the proximal segment, retention relies on triangularity, defined angles, and "U" shaped grooves.
Retention in the proximal box is entirely located in dentin.

Hand Instruments and Tools

Essential hand instruments for Class II prep include chisels (15-8-12), hatchets (15-8-14), GMT, and angle formers.
Wedges are used to depress interproximal gingiva, prevent injury to soft tissue, and minimize seepage of saliva through the rubber dam.

Cavity Preparation Techniques

Medial GMT can plane the gingival cavosurface margin, bevel mesio-pulpo axial line angle, and accentuate retention grooves in the disto-proximal box.
Distal GMT serves to plane the gingival cam of the disto-proximal box, bevel disto-pulpo-axial angles, and enhance retention grooves in the mesio-proximal box.

Diagnostic Techniques

Class II carious lesions are diagnosed using bitewing radiographs.
Lesions are identified in radiographs when they penetrate at least two-thirds into the enamel towards the DEJ.

Operational Guidelines

The occlusal external outline of the proximal box is determined by the extent of carious lesions and the need to break contact with adjacent teeth.
A minimum separation of 0.3mm should exist between the gingival cavo surface and the adjacent tooth's proximal surface.

Additional Considerations

Proximal depth at the pulp-axial line angle is greater than at the gingival floor due to varying enamel thickness.
Proximal contact points in maxillary teeth typically lie towards the buccal side.
The reverse curve allows preservation of cuspal triangular ridges and facilitates an angle between proximal walls and the tangent of the proximal surface.

Instrumentation for Examination

Examination instruments include a mouth mirror, explorer, calibrated condenser, and cotton pliers.

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Description

This quiz focuses on the essential principles of Class II cavity preparation, highlighting key concepts such as GV Black's approach. It covers outline form, resistance and retention, and considerations for pulpal floor depth. Perfect for students learning dental cavity techniques.