Depending on your subject, this can be just a minor tweak, or a major reconstruction. Luckily, in most cases, you’ll be able to fix most problems with teeth using the Liquify filter, but sometimes, you have to rebuild a tooth or two from scratch.
Here’s the image with teeth we want to retouch. First, let’s evaluate what we need to do: the two front teeth look a little too long compared to the other teeth (they should only be a little longer than the surrounding teeth). So, that’s one thing to fix. Then, I would remove the points from the canine teeth, and repair the gap on the canine tooth on the right. Lastly, I would straighten the bottom teeth.
Go under the Filter menu, under Distort, and choose ...