It has been said that dragon-fire could melt and consume the Rings of Power, but there is not now any dragon left on earth in which the old fire is hot enough; nor was there ever any dragon, not even Ancalagon the Black, who could have harmed the One Ring, the Ruling Ring, for that was made by Sauron himself.

Could a dragon have destroyed the Ring?

Smaug's dragon-fine would not have been hot enough to destroy the One Ring. The malevolence that Sauron put inside of the Ring could only be destroyed in the Cracks of Doom, so Frodo was compelled to make the journey to Mordor.

Can Smaug use the One Ring?

Probably not. Dragons are a lesser order of creatures, and since Sauron is both a Maia and master of the Ring, in any contest between Smaug and Sauron, Sauron would have prevailed. The Dragon Sauron might use with terrible effect. Smaug is therefore clearly subservient to Sauron.