The Class II Solution

Isolation is the next step - and making sure the restorative field isn’t contaminated with blood or saliva will be key to success.

Creating the best foundation for your Class II restoration depends on your matrix system. We recommend choosing a matrix system that:

• minimizes impingement of soft tissue allowing adhesive to perform at its optimum potential,
• creates a tight seal, and
• provides an anatomically correct form

like the Palodent V3 sectional matrix system or the Palodent 360 circumferential matrix band.

Avoiding Post-Op Sensitivity

Most dentists experienced in Class II restorations knows that postoperative sensitivity is a common problem, often caused by adhesive application technique mistakes. To minimize the chances of post-op sensitivity, avoid the following adhesive missteps:

• Over-etching dentin – Dentin exposure to etchant should not exceed 15 seconds.
• Over-drying dentin – Keep the dentin surface slightly moist prior to bonding.
• Solvents not removed during drying step – Keep in mind that each type of solvent (acetone vs. alcohol) requires a different amount of air thinning to completely volatize.
• Incomplete material coverage – Completely cover the entire internal surface of the cavity with the adhesive, ensuring it appears glossy rather than matte.
• Under curing – Choose a light that performs well at clinically relevant distances. 

While light curing may seem like the simplest part of a Class II restoration, it’s not as straightforward as you might think. Traditionally, clinicians have been led to believe that as long as the blue light is near the restoration for long enough, the restorative material will cure.

It’s not as simple as that, which is why more than 37% of composite restorations are being insufficiently light cured⁷. The amount of energy delivered by the curing light is what leads to a successful procedure. The more energy delivered to the Class II restoration, the stronger the material will be. An insufficient cure can lead to adverse effects on physical properties, reduced bond strengths, breakdown at the margins, increased potential for microleakage, and ultimately secondary caries and Class II restoration failure.⁸

To be sure you’re curing effectively, make sure to consider the following when using your light:

• Performance over distance: The #1 reason for Class II failure is recurrent caries, and the floor of the proximal box (often 8mm away from the tip of the light) is the most vulnerable interface. Be sure your curing light is effective over distance to avoid this.
• Beam uniformity: Hot and cold spots within the light beam may lead to a non-uniform cure across the restoration, which is why you want a uniform beam profile.
• Angle: Be careful with the angle of your curing light. The guide tip should be as close as possible and parallel to the occlusal surface of a Class II to have the best chance at allowing light to fill up the proximal box. Pen-style lights make it easier to maintain the proper curing angle when space is an issue – such as the back of mouth, and in geriatric and pediatric cases.
• Ergonomics and operation: A lightweight, ergonomic curing light design with simple controls may help reduce the opportunity for technique variability.
• Curing Cycle length: While you can’t overcure the composite itself, you CAN, in fact, deliver too much radiant energy to the tooth, causing an excessive increase in temperature which can cause sensitivity, and damage the pulp and oral tissues. The safest and most reliable approach is to deliver a lower intensity over a longer exposure time.

With the tooth prepped, matrix placed, and adhesive applied and light cured, it’s now time to place the restorative material.  The main challenge faced in this step is cavity adaptation at the floor of the proximal box.