There is a little metal showing on my dental crown. Is there any fix for this? (photo)

You have a crown that has a  metal coping and porcelain covering it.  The porcelain was probably thin due to the lack of space available for the crown.  It is only an aesthetic issue and functionally it will be fine.  Should you ever have another crown  make sure to request that it be "metal free."  Good luck. 

Sounds like not enough tooth structure was reduced when preparing for the new crown so to fit the new crown into place, the dentist removed the porcelain down to the metal. If it bothers you aesthetically, return to the dentist and have him redo it. Suggest an all porcelain zirconium crown which has no metal base and looks much nicer.

Your dentist appears to have ordered for you a crown with a nickel substructure covered with porcelain to make it look like a tooth.  Not enough of the tooth was removed from the chewing surface to allow for the thickness of metal and porcelain, forcing the lab to make the crown too big for the space.  The dentist then ground down the crown exposing the metal.  Though the metal showing does not endanger the tooth, if you want to replace the crown you may be able to remove it yourself without drilling by biting into sticky Milk Duds.  Then have the tooth shortened a little more where the metal shows through and have the dentist order you a full contour zirconium oxide crown which will need no metal layer underneath. 

You are seeing the metal understructure showing through the porcelain which is baked over the metal to make the crown look like a tooth.  Your tooth is relatively short so it is difficult to have enough room in these cases for the porcelain to be thick enough to cover all the metal.  It will not affect the longevity of your crown.

There is no fix for that except for replacing the entire crown.  The good news is that there is no harm to your tooth and the size of the metal showing is miniscule.  That being said, your dentist should have shown it to you and given you the option of having the lab redo it.  I'd leave it alone because it will be more trouble then it's worth to drill off the new crown and make a new one.

It can be patched with bonding or just leave it.  If the defect continues to get larger, then a new crown is in order with more space to accommodate the porcelain