sharpened

Your canine teeth can be sharpened by going to your dentist, where he/she will probably add a contour in place, but if you mean 'sharpened' like a pencil sharpened, then talk to your dentist about that.

The past tense of sharpen is sharpened and the past participle is also sharpened.

No, not every note is sharpened, or raised a half step. It's just that note. For example, in a measure, if the note A is sharpened, every A in that measure will be sharpened unless naturalized.

A shovel can be sharpened with the right tool in place.