WASHINGTON, June 12 (Reuters) - U.S. President Joe Biden postponed a meeting with the head of NATO and skipped his other public events on Monday to undergo his second root canal procedure in as many days, the White House said.

"The president is doing just fine and he will be certainly working in the residence this afternoon," press secretary Karine Jean-Pierre said following the treatment at the White House.

Biden reported tooth pain on Sunday, prompting an X-ray examination and root canal treatment by a team from Walter Reed National Military Medical Center, according to a letter from his physician that was distributed to the press.

"The President tolerated the procedure well," the physician, Kevin O'Connor, wrote about the previously undisclosed treatment. "There were no complications."

Biden, 80, experienced more pain on Monday, received local anesthesia and did not need to transfer his powers to Vice President Kamala Harris under the 25th Amendment of the U.S. Constitution, the White House said.

Biden's wife, first lady Jill Biden, commented on the procedure at a New York campaign fundraising event, saying she went to the dentist office at the White House to check on Biden and "he was under anesthesia. But he came up and he was good.”

Asked for clarification of her remarks, a White House official said Biden had simply undergone a local anesthesia for the procedure.

Root canal procedures are common to treat infected teeth that cause pain, especially for older adults, said Asgeir Sigurdsson, endodontics chair at New York University's College of Dentistry. Millions are performed each year in the United States with a near-universal rate of success, he said.

Two or more procedures are sometimes required to remove damaged tooth tissue and fully resolve the issue, Sigurdsson said. Local anesthetics used to numb pain during the procedure can make it difficult to speak for a few hours afterwards.

"Once you treat it properly, it will heal without any complications," said Sigurdsson.

Biden previously underwent root canal procedures in the 1990s, as a senator overseeing the Supreme Court confirmation hearings for Justice Clarence Thomas.

Biden is the oldest person to serve as U.S. president and both his age and health have been a focus of voters as he seeks a second, four-year term in the 2024 election.