PROVIDENCE — A Superior Court judge has upheld the firing of a Smithfield social studies teacher for stapling a student’s scalp during a classroom stunt three years ago.

Judge Daniel A. Procaccini ruled that the Smithfield School Committee, the state education commissioner and the state Board of Regents for Elementary and Secondary Education Appeals Committee showed “good and just cause” in finding that Bethany St. Pierre should be dismissed from her job as a Smithfield High School social studies teacher after injuring a student and then urging the class to cover it up.

While Procaccini acknowledged St. Pierre’s stellar teaching record over six years, he wrote that the court could not ignore that her actions could have compromised the well-being of her students.

St. Pierre, a popular teacher among students, would conduct her class in the spirit of a vaudevillian magic show in which she would cast herself as the master magician and a student as a volunteer from the audience, the decision states. One act included a “stapler trick” in which she held a loaded stapler close to the volunteer’s skull and created an impression that a staple hit the student’s head, when, in fact, it fell harmlessly into the volunteer’s hair.

In September 2006, however, the stunt went wrong and the stapler went into 15-year-old Shawn Lynch’s head, sending a trickle of blood down his face.

Realizing the injury, St. Pierre wiped the blood away and asked Shawn if he was alright. He said yes and she sent him to the bathroom to wash up, cautioning the students before the end of the class that mention of the incident should remain “within the classroom.” She did not direct Shawn to see the school nurse or notify her superiors.

Ten days later, the boy’s mother alerted Principal Daniel P. Kelly, who summoned St. Pierre to his office. During a meeting attended by a union representative, St. Pierre acknowledged the incident.

Supt. Robert O’Brien contacted St. Pierre by letter with concerns about the episode. After interviewing St. Pierre, he wrote her that he planned to recommend that the School Committee fire her.

That November, following a closed session in which the board heard testimony, the committee voted 4 to 1 that she should lose her job. Education Commissioner Peter McWalters and a Board of Regents appeal committee both upheld that decision.

St. Pierre then appealed to Providence County Superior Court, arguing her firing was unjustified because its basis did not amount to “good and just cause” under the state teachers’ tenure act. She asserted that the committee must show repetitive and intentional conduct to support termination and that “progressive discipline” would be the better course to take.

Procaccini wrote that while St. Pierre may have made a mistake, the record shows that she made four errors: performing the trick itself, failing to get medical attention for Shawn, failing to alert the principal and trying to cover up the episode with the help of students.

“[This] court finds that the intentional actions demonstrating and compounding poor judgment in an isolated incident can constitute ‘good and just cause’ under the act,” the decision states.

St. Pierre, 34, of Glocester, was initially charged with assault, but a District Court judge dismissed the count, saying “accidents happen.” She was also awarded unemployment compensation.

kmulvane@projo.com