As of version 8 of Capture One, users have been blessed with the ability to control white balance on an adjustment layer. This is useful for a number of reasons, but the biggest win for my workflow is a very simple, and very repeatable way to whiten and brighten teeth in Capture One.
For a change of pace, I recorded a video to demonstrate this technique. Steps are detailed out below.
Step One: Make you desired adjustments to the overall image
Step Two: In the Local Adjustment tool tab, create a new adjustment layer and call it "Teeth"
Step Three: Use the paint brush tool to paint a mask over your subjects teeth
Step Four: Use the local White Balance adjustment tool to reduce the Kelvin temperature of the masked area until you achieve the desired effect. You can also locally adjust exposure and/or brightness to further enhance the teeth.
I find this to be a really effective, easy, and easily repeatable way to enhance tooth that appear too yellow, while keeping your images in Capture One. I used to rely on Photoshop to do any teeth whitening I needed, which meant I made my adjustments in Capture One, then exported to Photoshop for further editing. Now I can keep 99% of my workflow in Capture One, reserving Photoshop for only major editing.