Class 3 Prep Dimensions Quiz & Flashcards

Questions and Answers

What is a Class 3 lesion?

Carious lesion on the inter proximal surface of anterior teeth not involving the incisal edge.

What are the contraindications for Class III composites?

An operating area that cannot be adequately isolated.

What clinical procedures are needed for a Class III restoration?

Anesthesia is usually necessary for patient comfort. 2. Occlusal assessments should be made to determine the tooth preparation design. 3. The composite shade must be selected before isolation. 4. The area must be isolated for effective bonding. 5. If restoration involves the proximal contact, inserting a wedge may assist in re-establishment.

What is the purpose of tooth preparation for a Class III restoration?

<ol> <li>Obtaining access to the defect. 2. Removing faulty structures. 3. Creating the convenience form for the restoration.</li> </ol> Signup and view all the answers

How do you access a Class III lesion from the facial approach?

Facial approach conserves tooth structure significantly. Signup and view all the answers

How do you access a Class III lesion from the lingual approach?

The facial enamel is conserved for enhanced esthetics, and shade matching of the composite is less critical. Signup and view all the answers

Which side should you access the Class III lesion if it is not seen from either side?

Access from the lingual side for esthetic reasons. Signup and view all the answers

Name the walls of the Class III preparation:

To be provided. Signup and view all the answers

What should be the dimensions of the Class III preparation?

Axial wall depth: 1-1.25 mm; Incisogingival length: 1.75-2.0 mm; Incisal extension at middle of contact area; Gingival extension should break contact with adjacent tooth. Signup and view all the answers

How should the anteriors be isolated with a rubber dam?

Canine to canine: use floss; Premolar to premolar: use retainers on both teeth. Signup and view all the answers

Describe the internal form of the Class III preparation.

<ol> <li>Incisal, gingival walls are parallel or slightly divergent, 90 degrees to proximal and lingual surfaces. 2. Facial wall is parallel to the lingual surface, 90 degrees to proximal. 3. Axial wall is parallel to the proximal surface, 90 degrees to the lingual surface.</li> </ol> Signup and view all the answers

What do you need to do to finish the Class III preparation?

<ol> <li>Smooth regular margins, with 45-degree bevels on accessible margins. 2. Well-defined walls and line angles. 3. Adjacent tooth must remain undamaged.</li> </ol> Signup and view all the answers

Why do we bevel the margins in preparation?

<ol> <li>Increases the surface area for bonding. 2. Provides a gradual transition from the restoration to the surrounding tooth structure for esthetics.</li> </ol> Signup and view all the answers

What kind of matrix band do we use on a Class III preparation?

A Mylar strip. Signup and view all the answers

What are the steps in restoring the Class III preparation?

<ol> <li>Select composite shade before isolation. 2. Isolate to permit effective bonding. 3. Use Mylar strip and place wedge below cervical margin. 4. Rinse, dry, and etch for 15-30 seconds.</li> </ol> Signup and view all the answers

Study Notes

Class III Lesions

Carious lesion located on the inter proximal surface of anterior teeth, excluding the incisal edge.

Contraindications for Class III Composites

Inadequate isolation of the operating area prevents effective bonding.

Clinical Procedures for Class III Restorations

Anesthesia may be required for patient comfort.
Conduct occlusal assessments to inform tooth preparation design and restoration function.
Select composite shade before tooth dehydration occurs.
Ensure proper isolation for effective bonding.
Use wedges to help re-establish proximal contact if the restoration involves the proximal area.

Purpose of Tooth Preparation for Class III

Access the defect directly.
Remove defective structures, including caries and prior restorations.
Design convenience form for optimal restoration placement.

Accessing Class III Lesion from Facial Approach

Accessing from facial conserves tooth structure significantly in cases of facially positioned caries or irregular alignment.

Accessing Class III Lesion from Lingual Approach

Preferred for better esthetics as it conserves facial enamel.
Color matching of the composite is less critical.
Discoloration is less noticeable, enhancing the restoration’s aesthetic longevity.

Accessing Non-visible Class III Lesions

If the lesion is invisible from either side, a lingual access is preferred for aesthetic reasons.

Dimensions of Class III Preparation

Axial wall depth: 1-1.25 mm.
Incisogingival length: 1.75-2.0 mm.
Incisal extension: at the middle of contact area.
Gingival extension: should break contact with adjacent tooth (1.75-2.0 mm).
Facial extension: approximately 1.5 mm to clear facial contact area.
Incorporate a 45-degree bevel at the cavosurface margin.
Maintain a rectangular outline shape with rounded internal line angles.

Rubber Dam Isolation for Anteriors

For canine to canine: use floss for isolation.
For premolar to premolar: apply retainers on both teeth.
Utilize retainers 212 and 9 for anteriors; retainers W2 and 212 for premolars.

Internal Form of Class III Preparation

Incisal and gingival walls should be parallel or slightly divergent, at 90 degrees to proximal and lingual surfaces.
Facial wall remains parallel to the lingual surface and at 90 degrees to proximal.
Axial wall parallels proximal surface, also at 90 degrees to lingual.
Primary retention achieved through bonding techniques.

Finishing Class III Preparation

Smooth and regular margins established, with 45-degree bevels where accessible.
Walls should be flat, smooth, and with well-defined line angles.
Ensure no damage to adjacent teeth.

Purpose of Beveling in Restorations

Increases surface area for improved bonding.
Facilitates a smooth transition between restoration and tooth structure for enhanced aesthetics.

Matrix Band for Class III Preparation

Utilize a Mylar strip for better visibility and flexibility than metallic bands.
Allows for light curing through the matrix.
Position wedge below the cervical margin to prevent overhang and stabilize the mylar strip.

Steps in Restoring Class III Prep

Select composite shade before tooth dehydration.
Isolate the area to ensure effective bonding, employing Mylar strip for light curing.
Rinse, dry, and etch the preparation for 15-30 seconds, extending 1 mm beyond margins before rinsing again and drying lightly.

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Description

Test your knowledge on Class III Composite Restorations in clinical dentistry. This quiz covers important definitions and procedures related to class 3 lesions. Perfect for dental students and professionals looking to reinforce their understanding of restorative techniques.