The playwright is an orthodontist, the director is a nurse, and the lead actress an astronomer, but “The Faith of David” is not community theater. The creative forces behind the show, debuting tonight at the Emerson Majestic, have visions of Broadway.

      The musical’s author, Craig Costanza of Revere, is negotiating with New York investors to put his production on the Great White Way. The four-day Boston run is a chance to gauge gudirnce reaction and possibly win over potential backers.

     If the show clicks, the orthodontist could find himself the Tim Rice of the tooth world. “How many times does anybody get an opportunity like this? I’m so lucky to be where 1 am,” Costanza said. “I’m enjoying every day of it, for however long it lasts.”

     Most shows fade long before they get near Broadway. Nicholas Martin, artistic director of the Huntington Theatre Company, said it usually takes a decade to get a musical up and running. Even a show such as “Suessical the Musical,” which had name recogniotion, was developed in workshop in Toronto before it began a pre-Broadway run in Boston.

     “No matter how good a show is, the chance of it getting to Broadway is a long shot,” Martin said.

     Tonight’s debut is the culmination of 20 years worth of work for Costanza, who was inspired to write “David” when the then-dentistry student read a story about David that went deeper than his encounter with the giant Goliath.

     “I was absolutely amazed at the amount of tragedy he faced in his lifetime. He was also inredibly multi-dimensional. He was a musician, a poet, a warrior, a prolific writer, and a king. I really identified with that side of him.”

     Like David, Costanza has also spent his life juggling diverse talents. He began playing the piano at age 8, spent afternoons in his  asement as a boy recreating scenes from “West Side Story” with friends, played the drums, and worshiped “The Sound of Music.” When it came time to choose a career, he looked to his family history to guide him. Costanza isn’t the first member of his family to show a talent for music.

     His father was offered a full scholarship to the New England Conservatory, but he chose to enter dentistry, a more stable profession than music, The younger Costanza flip-flopped between dentistry and music. At one point he dropped out of Boston University to study keyboards at Berklee but returned to BU and earned his dentistry degree. 
     Music remained in his life after he set up his dentistry practice. He played keyboards in bands, all the while tinkering with the script for “David.” In 1984, he grew totally frustrated with the project and shelved it, He didn’t pick it up again until almost 10 years later.
 
     Working alone on the script for three years, he called on a cojlege buddy, Rich Mutkoski, to help him finish it. Like Costanza, Mutkoski was torn between music and the sciences. He graduated with a dual degree in biology and music, and works for a pharmaceutical company. They added composer Tim Murner to the team, and the trio finished the script last year and began casting. Instead of waiting for Guffman to stumble across his work, Costanza saw the potential of his musical and began making plans to get it to Broadway. He hired a publicist,  and he has a team of industry insiders repre- senting him in New York negotiations. Although he hired a local cast of 75 for the Boston run, “David” is not & low-budget production. The price for the four-day run is about $100,000. Mutkoski is paying more than half out of money he earned in the stock market; the rest is from corporate sponsorships and local investors.
 
     “I have a great deal of faith in this show,” Mutkoski said, “not only that it will be successful in Boston but that it will be going on from there.” Both Costanza and Mutkoski have worked long hours on the play, in addition to working full-time jobs and trying to find time for their families. But as they gear up for tonight’s premiere, they say they’re glad they endured so many nights with so little sleep to see their dream come true.
 
     “1 used to sit here and write and imagine that David and all the characters were here in the room with me,” Costanza sald. “Now they’re actually here, They’re alive and on stage. It’s amazing to see the rehearsals. Even if it only went this far, I’d be thrilled. But I think we’re going a lot further.”