Cano missed four games following the dental work. He singled twice off James Shields, already picked to start on opening day. The Royals ace later picked off Cano at third base.
The new Mariners second baseman also started a double play to end the first.
Alex Gordon doubled in two runs during a five-run third for the Royals.
Kansas City catcher Salvador Perez left after two innings with a bruise on his left palm after being hit with a foul tip.
Preliminary X-rays did not show any further damage and manager Ned Yost said the injury wasn't serious.