No, I don't think that there is one "best fingering" for scales. In fingering a scale, players will usually attempt to limit the number of shifts and will also try to determine the best places for necessary shifts to occur. This will often come down to player preference. Scales should also be kept within a given position. In other words your fingers should rarely have to cover more than a 4 fret span--shifting is usually preferred over stretching. Awkward string crossings may also be considered, but since most exams require you to prepare a number of different right hand combinations, this is not always practical.
The latest edition of the Royal Conservatory of Music's technical guide now states that any reasonable scale fingering will be accepted of exams--more evidence that there is not one best way to finger a scale.
Edit--If you trust your teacher, than it may be best to use his/her fingerings.