Last October, after taking a high stick to the mouth that left his two front teeth comically chipped, Bruins winger David Pastrnak decided to have some fun with it.

Declining dental work, the now 21-year-old quickly posted a photo of himself to Instagram, where the new look drew rave reviews, and before long, the jagged grin had become something of a trademark — much to the delight of the team’s fans, and much to the chagrin of a certain mild-mannered gentleman named Edwin “Ted’’ Riley III.

“Look at that Jack-o’-lantern smile,’’ Riley said recently, shaking his head as he watched a pregame interview in which Pastrnak’s broken grin was on full, high-definition display. “Just don’t tell them who your dentist is.’’

That would be Riley, the man who for the past quarter-century has been charged with patching up the mangled smiles of the city’s professional hockey players. He’s the Bruins’ team dentist (did you know they had one?), and in a sport that’s taken more teeth than sugar — where flying pucks, sticks, and fists very often wind up in a player’s mouth — he has proven to be a good person to have around.

Over the years, he has been called upon to handle nearly every dental debacle imaginable. Cracked teeth. Broken teeth. Missing teeth. Mangled lips.

He once saw a player take a stick to the mouth so hard that it lifted the guy’s gums right off the bone. Another time, a current player had part of a tooth broken off mid-game. The trainer plugged the bleeding and the player returned to the ice, scoring a goal. After the game, a surgeon was stitching him up in the team’s medical room when Riley raised the question of where, exactly, the tooth had ended up. They found it embedded in the player’s lip.

During games, Riley can be found sitting quietly in his appointed TD Garden seat — section 19, row 17, seat 15 — watching the action and waiting patiently for his cue: a player suddenly grabbing for his mouth, a text from the trainer.

Most players refuse to sit out because of a lost tooth, so Riley, armed with a small dental kit, does what he can in the team’s medical room — a little something to stop the pain or the bleeding — before handling the heavy lifting during follow-ups at his downtown office.

Assuming, of course, he can persuade the players to show up.

“Some of the toughest guys [on the ice],’’ he explains, “may be the scaredest guys when it comes to dental work.’’

Born and raised in Boston, Riley was running his own practice downtown in 1993 when a friend and oral surgeon asked if he wanted to help out with the Bruins. He began filling in occasionally, and when the friend left for Long Island the following year, Riley was offered the job full time.

He accepted in large part because it came with an extra game ticket, which almost always went to his dad, a rabid Bruins fan who had no problem letting his son’s new employer know how he felt. “We’re sitting six rows behind the bench, and he’s screaming at the coach, at the players, anybody,’’ Riley says. “I’m like, ‘Dad, come on, you’ve got to cool it; I’m the dentist here.’ ’’

Over the years, it has remained something of a family affair, with Riley’s dentist son, Ed Riley IV, now covering games as well. The two work only home games, but treat injuries of Bruins’ foes as well.

Like many fathers and sons, the two often bond over Bruins hockey. Unlike many fathers and sons, the conversation typically centers on, as the younger Riley puts it, “which player doesn’t wear a mouthguard, or this guy got hit in the mouth, or this guy went down and was holding his face.’’

Despite the sport’s physical nature, however, a typical day at the office has become far less perilous over the years.

Faceguard requirements and the increased use of mouthguards have helped protect against pucks and sticks. And current rules preventing players from removing their helmets during fights mean would-be brawlers are more likely to require a hand surgeon after a dust-up than a dentist.

In an era in which they’re constantly on camera, meanwhile, today’s players seem far less willing than their gap-toothed brethren of yore to put pearly whites in harm’s way.

“In the old days, if you had a few teeth missing, that was thought to be a badge of courage as far as a hockey player was concerned,’’ says Bill Blair, past president of the NHL’s Team Dentists Association and longtime dentist for the Calgary Flames. These days, he says, “society demands that you have a good smile.’’

For Riley, it’s been quite a run. Through four general managers, 10 coaches, and too many players to count, the job has represented a constant, welcome distraction, a front-row seat to the city’s best show on ice. Sometimes, too, it’s been more than that.

Four years ago, Riley’s wife of 45 years was diagnosed with a brain tumor. Early treatment appeared successful, but within two years, it had returned with a vengeance. Toward the end, as Riley spent much of his time at her bedside, his only real reprieve from the grief came during the handful of trips he’d make over to the Garden.

“It gave you a couple hours where you didn’t have to think about everything else,’’ he says.

Stationed in his customary seat during a recent weeknight game, Riley kept a watchful eye over the ice below, cringing when pucks went screaming by at face-level, ducking out between periods to drop by the locker room and make sure all teeth were accounted for.

Over the years, he has come to measure a successful day’s work by two main criteria, and as the Bruins held on to beat the Las Vegas Golden Knights, 2-1, he took solace in the fact that — on this night, at least — he could go home happy.

“A win and no injuries,’’ the old dentist says, smiling. “That’s a great night.’’

Dugan Arnett can be reached at dugan.arnett@globe.com.