Impacted canine tooth extraction?

The upper cuspid has the biggest root in the mouth and there is a reason for that - it helps provide lip support for the corners of the mouth. A baby cuspid is not large enough to do that and leaving it in place will usually cause the corner of the mouth to droop. The massive root of the upper cuspid and the crown as well help to prevent the mouth from looking like it sags or frowning. Although all your teeth may be perfectly straight, the only way to bring the cuspid down is to use all the teeth in your mouth for anchorage to help pull that big tooth down. It would be a mistake to have the impacted cuspid extracted and pulling it down is not considered "cosmetic" but necessary. If you choose not to have the impacted cuspid erupted orthodontically, the disfigurement it causes will become more and more obvious as you get older.