Open your image.
Make a selection of the teeth by using one of the lasso tools and/or magic wand tool.
Now we’re going to refine the edge of our selection.
Go to Refine Edge or Select > Refine Edge (Alt + Ctrl +R).
Now give some Feather by sliding the slider towards the right. The amount of feather may vary depending on the size of the image and the resolution.
Then click Ok.
Will now turn this selection into the layer mask.
Make a new layer and place it under a group by pressing Ctrl + G.
select the group and click on layer mask.
The selection that you had will turn into the layer mask.
Now we’re going to tackle the color by going to the adjustment layer.
Check the Colorize option & slide the Hue slider almost all the way to the left. In my case, I’ve set it at 28. Adjust the saturation levels as well. In my case, it’s at 25.
To take the Dark areas in the teeth, go to the Adjustments Layer again, select Curves. Select the Curves Layer and double-click on it. This will open up the Layer Style dialog Box. Now Alt + Click on the Underlying Layer Slider right pointer. This will split the pointer into 2. Now move the left half of the newly created half and slide it to the right to your liking. Same with the right half, but not too much left.
Now we’ll take care of the lighter areas.
Create a new Layer inside the group. Select the Marquee tool and select the entire teeth area.
Now open Edit > Fill. And fill the entire area with white.
Now double-click on the recent created layer to open the Layer Style dialog box. Go to the Underlying slider & this time select the left slider arrow (the dark one) and Alt + Click to split in half. Move the right half of the pointer as far to the right as how much you need. Then do the same with the left half till you get desired results. You can also play with the opacity.
The final output!
Check this out while you wait!