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 groundball 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.
Mike Moustakas singled twice and drove in two runs for the Royals. Billy Butler doubled, singled and scored twice.
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.
Royals: Shields pitched 4 2-3 innings and allowed two runs on five hits, throwing 65 pitches.
"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."
Mariners: Maurer's second spring training start ended after he allowed three straight singles and a run with two out in the third inning. He lasted 2 2-3 innings and allowed four runs on six hits as he tries to stay in contention for a spot at the back end of the starting rotation.
"Got a little tired," Maurer said after 47 pitches. "Definitely a little tired the second time out there. Liked the way the changeup worked today, so that's a plus."
Cano and Shields relived the strange pickoff play Shields executed to catch Cano off third base in the fourth inning.
Shields said Cano told young teammate Abraham Almonte during the game to be wary of his pickoff move. But Shields caught Cano despite the warning.
"Spring training or not, we're still working on stuff, too," Shields said.
"It's good that he did it now," Cano said. "Now we know during the season what's he's got. He got everybody, even the third base coach. Nobody saw anything."
Royals outfielder Jarrod Dyson had an interesting day in center field. He robbed Smoak of extra bases with a leaping catch at the wall that turned into a sacrifice fly in the first inning. But he misplayed a line drive hit by John Buck that zoomed over Dyson's head and off the wall for a double in the fifth. "I looked like a rookie ball outfielder on that play," Dyson said.
Royals: 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.
Mariners: Right-hander Taijuan Walker threw long toss without pain Sunday as he recovers from shoulder soreness, but has yet to pitch in a spring training game.