My top right front tooth is longer than my left front tooth. Is there anyway my dentist could make it the same length?

A set of photos would help greatly in advising you on the best option for correcting your front teeth, but here are a few things that come to mind.  The shorter tooth could be lengthened using composite bonding or a porcelain veneer.  The longer tooth could be slightly shortened using a fine bur if the length difference is really small.  The bottom line is that one way or another the discrepancy can be corrected to give you even symmetry with your front two teeth.  Good luck.   

Yes, it can be done by either lengthening one or shortening the other.  The first thing I would do is try and find out if one looks too long or the other looks too short.  A small change can be made by adding composite (plastic) or shortening the enamel by drilling.  larger changes would probably be best done with porcelain, either lengthening or shortening.

Without a photo it is difficult to say what the best solution is. They range from filing down the longer tooth(if the difference is minimal) to building up the shorter one. An assessment of your overall bite would be beneficial as you may have other teeth in your mouth that are of different length. If this is the case then orthodontics may be a better long term solution. A photo would allow for a more accurate treatment plan.