All Owen Bennion wanted for the first show of the summer was his two front teeth.

Unfortunately, as of about 11:35 a.m. Friday, he pretty much no longer had them.

Owen is the new musical director of the Vineyard Sound, a popular college a cappella group that sings a regular schedule of hourlong shows across the Island from the middle of June until the middle of August. On Friday evening, the 16th season of Vineyard Sound was scheduled to begin with two performances at St. Andrew’s Episcopal Church in Edgartown.

You’ve heard the old expression “The show must go on.” Well, after what Owen and the rest of the Vineyard Sound went through on Friday, you’d have to ask the question, “Up to what point, exactly?” And then as the day wore on, probably just a plain old “Why?”

Let’s hit the bottom line right now: All ten guys in the Vineyard Sound sang both shows, the first at 7 p.m. (traditionally geared to families with young children), the second at 9 p.m. (for a crowd that can stay up later).

Now read how the rest of that Friday the 13th played out for a group of five veteran and five rookie singers who all woke up with a healthy case of the opening night jitters anyway.

Early in the morning, the Vineyard Sound drove to the Oak Bluffs school, where they sang doo-wop and some funkier stuff for kids and teachers. After returning to the group’s house off the Edgartown-West Tisbury Road, three veterans (Owen Bennion, Allie Levey and business manager Dan Carroll) and three rookies (Andy McCulloch, Matt Lipkins and Eddie Silva) piled into Allie’s Toyota Camry and drove to Edgartown to play a little three-on-three at the elementary school basketball courts. They arrived at 11:30 a.m.

Five minutes later, Owen was driving down the baseline for a layup, the score 4 to 2 and Eddie, having sunk three, playing the game of his life. “I posted up on him,” said Dan of Owen, “and he put a shot up, and he fell off to the side, and the next thing I heard was this ‘tink!’”

“When I came down,” said Owen, “I remember seeing the post here” — he put his palm an inch in front of his face to mimic the steel stanchion to the backboard — “hitting it, falling, and then spitting out my teeth.”

“I keep going back to it,” said Andy on Saturday afternoon, looking at Owen across a patio table at the house. “I mean, your teeth made direct contact with a six-inch by six-inch metal pole. You took off paint!” Matt recalled seeing the dental fragments lying on the court. He picked them up and showed them to Owen. “Found your teeth,” he said, trying to be as helpful as he could.

Owen’s right front tooth had snapped off almost horizontally at about the halfway point. The left front tooth was jagged, with the outer edges more or less intact but the center cut away almost to the root. There was remarkably little blood and no larger injury to the face. Yet as Owen cheerily recalled the more graphic personal turns in the story on Saturday, Dan pulled his Irish cap down over his eyes, Andy lowered his forehead onto the table and Matt winced a bit and said quietly, “Ungh. I can still hear it in my head: ‘Ping!’ Like a golf ball.”

Dan pronounced the game over and the six headed for the hospital. But he let the three rookies off at Sharky’s in Edgartown, partly because he felt there were now too many men in the car, and partly because, well, it was lunchtime.

For the next three hours, Owen waited at the emergency room, calling his mother Masayo, a medical technician in Seattle, for guidance. While the E.R. staff tried to find an Island dentist who could minister on short notice to an a cappella singer with mouth trauma, Owen’s mom dialed dentists on the Cape, who either did not answer or could not help. She also tried Owen’s uncle, Dr. Eric Rubin, a staff member at the Harvard School of Public Health, to see if he knew a dentist in Boston, if it came to that.

Meanwhile, Dan, only two weeks into his inaugural tenure as business manager, drove home from the hospital with Vineyard Sound veteran Tatsuya Adachi and newcomer Matt Ungaro, who’d come to the hospital with Owen’s wallet and cell phone. With two opening night shows advertised in the papers for that evening, Dan tried to figure out how — if necessary — two hours of a cappella singing might be stitched together without a musical director who also sang complicated harmonies ranging from tenor one down to baritone.

“The first thought that went through my head — I didn’t want to say it to you, Owen — was, ‘If Owen isn’t going to do the show tonight, do we have to pay him?’” said Dan.

The hospital found a dentist in Edgartown who would take Owen after the last scheduled patient of the day. With Allie Levey, Owen arrived at the Triangle offices of Dr. Brian S. Cullen around 3 p.m. He got into the chair at about 4:45 p.m. and Dr. Cullen began to fashion and bond caps that could serve Owen not just that night — if they could be finished on time — but for up to seven years.

As Dr. Cullen worked, Dan and Allie met for a late lunch, wondering how they might do their first shows without the musical director and marveling at Owen’s spirits, which never seemed to flag. “Hey, the whole process was really interesting to me,” said Owen. Dr. Cullen “gave me a hand-held mirror, and I was watching the whole time.”

Back at the house, the news had spread and the mood had tightened, but not for reasons anyone had expected. “When I woke up, I thought I was going to be very nervous, running over my part all day, trying to figure stuff out,” said Andy, a rookie and one of the basketball players. “But then Owen’s teeth fell out. Whaddaya know? So everything just got shifted.”

Dan arrived at the house and laid out scenarios from ideal (two shows, on time and at full-strength) to catastrophic (no shows): He ironed all the Vineyard Vine uniforms of Oxford shirts, khaki shorts and printed ties. A little after five o’clock, the group set off for Edgartown and St. Andrew’s Church.

From Dr. Cullen’s office, Allie called to say that the oral surgery was taking longer than expected — the right tooth, heretofore well-anchored in Owen’s mouth, had suddenly loosened a bit at the root and needed rebonding. He and Owen would not arrive at St. Andrew’s much before 7:15 p.m. Owen’s face would still be a bit numb from the Novocain, but otherwise their conductor would be unmedicated and able to harmonize. Listening to news of the delay on his cell phone, Dan thought to himself, “Friday the 13th sucks.”

Owen rolled out of the chair and scheduled a follow-up appointment with Dr. Cullen and his assistant. At 7 p.m., the moment the show was supposed to begin, Allie and Owen drove out of the Triangle parking lot and headed downtown. Owen, his amalgamated front teeth tender but looking normal, began to draw up a set list for the first show in the passenger seat of the car. The church was six minutes away.

At St. Andrew’s, Dan told the audience: “‘We’re not going to be starting until 7:15. If you don’t want to hang out, that’s fine.’ ” But people still kept coming in. “I didn’t want to be a jerk and say we’re not going to have a show after they’d sat down. Some people come out just to see the first Vineyard Sound show of the year,” he recalled.

At 7:10 p.m., Owen and Allie pulled in. Dan had pre-tied the ties in the collars of their shirts. As Owen changed, he dictated the set list for the first show to Dan, cutting out the two leads he himself might have sung (Southern Cross and Cupid). They went on stage at 7:16 p.m., with no warmup for either Owen or Allie. “When I started the show, the lip area and the back of my nose were still numb,” said Owen. “I could feel the front of my nose.”

There were 40 people in the house. “We killed it,” said Dan of the first performance. “Everybody [in the group] really picked it up,” added Owen.

Between shows, Owen worked his way around a quiche and a soda from Espresso Love. He hadn’t eaten anything (except for the pole, said Dan) since breakfast. Forsaking the Advil his fellow singers had bought him, Owen sang Southern Cross and Cupid at the 9 p.m. show.

“My voice was fine,” he said. The difficulty was “mostly forming consonants — and especially loud consonants . . . Pretty much I had to keep my tongue in the back of my mouth and click the hard consonants off the roof of my mouth.” Otherwise, he thought the second show went fine too.

In honor of his ordeal, Dan Carroll declared Saturday to be Owen Bennion Day at the Vineyard Sound house. That meant mandatory Allman Brothers played on the stereo every hour, one of Owen’s favorite bands.