Clinical Protocol for Class II Composite Restorations

This document outlines the systematic procedure for performing a Class II restoration, covering preparation, matrix placement, bonding, and finishing techniques.

1. Initial Preparation and Tooth Protection

Before beginning the preparation, place a wedge underneath the proximal contact

between the target tooth and the adjacent tooth. This serves to protect the adjacent tooth from accidental damage during the procedure.

Occlusal Step

Initial Penetration: Use a bur to penetrate the occlusal surface to a depth

just inside the dentino-enamel junction (DEJ).

Extension: Extend the preparation mesio-distally and buccal-lingually.

Preservation: Maintain the integrity of the cusp tips while ensuring all caries are removed.

Proximal Box Preparation

Ditch Cut: Using a 245 bur, create a ditch cut along the DEJ.

Enamel Shelf: Extend to full depth while maintaining a thin shelf of enamel between the bur and the adjacent tooth.
Breakthrough: Gently move toward the adjacent tooth until the enamel shelf breaks free.

Refinement: Smooth the pulpal floor and axial walls

. 5. Hand Instrumentation: Use an enamel hatchet to trim “hooks” or spurs of enamel at the corners

and remove any unsupported enamel.

Retention and Final Adjustments

Retention Grooves: For added stability, place proximal retention grooves or divots just inside the DEJ using a quarter-round

or 169L tapered fissure bur.

Occlusal Dovetail: Ensure a dovetail is present at the mesial pit

to prevent proximal displacement.

Surface Texture: Roughen the walls with a coarse diamond bur

to increase surface area for bonding.

Clearance: Verify a clearance of approximately 0.5 mm

from the adjacent tooth.

2. Matrix System Placement

Proper isolation and contouring are essential for a successful Class II restoration.

Matrix Selection: Place a sectional matrix or a Tofflemire band.

Ensure the inferior portion is seated below the gingival cavosurface margin.

Wedging: Reinsert the wedge underneath the proximal contact, ensuring it is outside the matrix band to push the band firmly against the prepared tooth.

Ring Placement: Deliver the sectional matrix ring so the ends straddle the wedge or sit between the band and wedge.

Burnishing: Use a round or flat instrument to burnish the matrix band against the adjacent tooth

to ensure a tight proximal contact.

3. Bonding and Composite Placement

Etching and Priming

Step	Action	Duration
Etch	Apply 30–40% phosphoric acid to the entire preparation.	15–20 seconds
Rinse	Wash thoroughly with water and high-volume suction.	10 seconds
Dry	Gently air dry; leave dentin slightly moist to prevent collagen collapse.	N/A
Bond	Apply prime and bond adhesive with a micro-brush; air thin.	10 seconds (Cure)

Incremental Placement

First Layer: Place a 2mm increment into the proximal box.

Compact with a blunt instrument (dip the instrument in adhesive to prevent sticking).

Polymerization: Light cure for 20 seconds

(or per manufacturer instructions).

Anatomy Build-up: Continue incremental placement until natural anatomy is restored.
Marginal Ridge: Carefully contour the final layer against the matrix band

using a ball burnisher or composite instrument.