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.
"Not a lot of pain, swollen a little bit," Cano said. "Good to get it done and now I'm back with the guys."
The new Mariners second baseman also started a double play to end the first.
Cano said he's working on his swing in spring training and discounts his power numbers because of how the ball flies in Arizona. He was glad to get a ground ball on the hard infield early in the game, which he turned for a double play.
"Robbie's a great talent and he cares about his job. It showed today," Mariners manager Lloyd McClendon said.
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.
Shields pitched 4 2/3 innings and allowed two runs on five hits, throwing 65 pitches. He stuck out five in his third and longest start of spring training. The runs were the first Shields has given up this spring.
"There's no sense in trying to break out everything right away. Trying to build arm strength right now," Shields said. "Body's feeling good and it was nice to be at 65 pitches."
Perez exited the game after the second inning with a bruise on his lower left palm, the result of a foul tip. His first X-ray was negative for any further damage and Shields said Perez wanted to stay in the game.
Manager Ned Yost isn't concerned about the injury to his top catcher.
"Really precaution. It was just a bit of a bruise," Yost said. "If it's one of those season deals, we wouldn't even think twice about it."
Second baseman Omar Infante played his first spring training game in the field as he returns from a shoulder injury. He said needs to get more power behind his throws. "I was pleased with his at-bats and he looked great in the field," Yost said.