Injectafil used to lower stress in high "C" factor restorations- By Thomas W. Mitchell, DDS, FAGD

Introduction: 

Injectafil is a dual cure composite offered by Apex Dental Materials. As it chemically cures it releases the polymerization stress which is a big cause of sensitivity or even fracture in high “C” factor preps (all class 1's and those with tall, thin cusps). If you allow it to reach the gel stage most of that stress will be released. It's really not wear resistant enough to withstand occlusal forces (except for pediatrics) so you need to top layer it with a paste composite. In this case I'm replacing a couple of deep occlusal amalgams.

Thomas W. Mitchell, DDS, FAGD
30-31 old amalgams showing wear and she wants them replaced.
Thomas W. Mitchell, DDS, FAGD
Pretty deep preps. High “C” factor.
Thomas W. Mitchell, DDS, FAGD
After 20-30 seconds of etching with Clean and Boost. Then rinse and dry and apply Bondsaver D. Let that dwell for 5 seconds and lightly blow off any puddles, leaving the surface damp. Then I "slobbered" on one coat of Superb, dried that completely to evaporate all remaining water and solvent, added two additional coats of Superb and blew off the solvent. Then place WO Titan flowable over the deep areas and co-cured for 3 seconds with the Valo light set on XTRA POWER, or 3200mW/cm2.
Thomas W. Mitchell, DDS, FAGD
I squirted a layer of Injectafil into the bottom 1/2 of each prep. Then waited for it to reach it's gel stage (about 30 secs). Then added a couple of seconds of light with the Valo light on Standard Power so the top of the Injectafil is hard enough to layer composite over it.
Thomas W. Mitchell, DDS, FAGD
Then layered and shaped Exquisite Restoration over the Injectafil. Here I did my usual lingual layer, shaped and cure for 3 secs with the Valo light set on XTRA POWER, then repeat for the buccal layers.
Thomas W. Mitchell, DDS, FAGD
I adjusted occlusion, pumiced off the blue marking paper and sealed the restorations with another addition of Superb (air thin and light cure).

Conclusion: 

This is a great use of Injectafil. It replaces additional layering of your paste composite and letting it gel before adding light allows it to release it's shrinkage stress to protect these high “C” factor preps and tall weak cusps from curing damage. Just top layer it over with your paste composite and you'll have a great long lasting restoration without those stress/sensitivity issues. Hope this helps.

Case by: 

Thomas W. Mitchell, DDS, FAGD