Pulse Curing Composite To Avoid White Lines- By Thomas W. Mitchell, DDS, FAGD

Introduction: 

Most composites shrink so much and with so much force/stress that they'll literally pull enamel crystals off the margin. There's only a couple that truly have low enough shrinkage stress that we don't have to worry about this damage. Exquisite Restoration (Apex Dental Materials, Inc.) is the best of the ones available.

The white lines we see at margins are the result of this shrinkage stress damage. We can't change the amount that the composite will shrink, but we can change the rate of shrinkage, allowing it to release that stress slowly enough to prevent damaging the margin. We do that by adding light a little at a time, and that's called "Pulse Curing". If you're using a composite other than Exquisite Restoration, we highly recommend pulse curing any layer that is in contact with enamel.

Thomas W. Mitchell, DDS, FAGD
This is #14 DO on my millennial assistant. That's a DO composite I did last year and she's crushed it. Today I'm trying to show how well pulse curing prevents white lines, so I'm using a micro-hybrid with approx. 2.2% shrinkage, which I know from past experience will develop white lines if I don't pulse cure.
Thomas W. Mitchell, DDS, FAGD
This is a Greater Curve band that I needed because the gingival margin is so deep. Not great adaptation on the buccal and lingual so I know I'll be doing some disking. This photo is after Clean and Boost dentin and enamel cleanser was applied for about 20 seconds, then rinsed and dried.
Thomas W. Mitchell, DDS, FAGD
This is after rewetting the prep with Bondsaver D (bond degradation preventer), 3 coats of Surpass 2, completely dry off the solvent, 1 coat of Surpass 3, air thin that and add a thin layer of Titan Flowable composite, then co-cure it all together for 10 secs with the Valo light on Standard power, 1000 mW/cm2.
Thomas W. Mitchell, DDS, FAGD
Then my first layer of composite against the distal matrix, condensed and shaped using Seamfree wetting resin, then Pulse Cured for 3 seconds from about 1 cm away with the Valo light on Standard Power. I do know that Dr. John Kanca has been pulse curing with his Valo on XTRA POWER but for only “1 second”, so if you want to use that setting on the Valo go ahead.
Thomas W. Mitchell, DDS, FAGD
This is the second layer, completing the occlusal surface, and “Pulse Cured” for 3 seconds from 1 cm away. Limiting the amount of light we're blasting the composite with at one time is the key to preventing white lines.
Thomas W. Mitchell, DDS, FAGD
Then final contouring with 3M Softflex red discs.
Thomas W. Mitchell, DDS, FAGD
And after checking the occlusion, I quickly glaze and seal the surface by cleaning it with Clean and Boost, then a quick coat of Surpass 2, dry completely and a thin coat of Surpass 3. Then comes the final curing of 10 seconds from each direction. Note: there are no white lines along the margins.

Conclusion: 

For composites other than Exquisite Restoration, I recommend you take the extra time to go thru the pulse curing protocol to prevent damaging the enamel margins. We've previously shown curing bulk fill Exquisite Restoration with the Valo light set on XTRA Power for only 3 seconds and not developing white lines. If you have a Valo light and want to turn up the power to really shorten down the curing time that's great with Exquisite Restoration composite, but probably not for others yet.

Case by: 

Thomas W. Mitchell, DDS, FAGD