In May 2014, while sitting at his desk eating a bag of nuts, the man bit down and cracked a tooth. In desperate need of a dentist, he Googled and found the offices of Bilal Ahmed, who had a practice in Northwest Washington.

Ahmed told the patient that the tooth had to be extracted and that he had to use nitrous oxide, commonly known as laughing gas, for sedation during the procedure.

The patient said he woke to find his anesthetic mask askew and the dentist forcing him into oral sex. Prosecutors later determined that the 31-year-old was not Ahmed's only victim.

In D.C. Superior Court on Friday, Ahmed was sentenced to 16  1 /2 years in prison for sexually assaulting five patients and one employee between 2010 and 2014.

Ahmed, 45, was arrested last year and charged with the string of attacks in his offices at Universal Smiles, at 2311 M St. NW in the District's West End. The office is closed and Ahmed's license has been revoked. In May, he pleaded guilty, with charges including first-degree sexual abuse of a patient, four counts of second-degree sexual abuse of a patient and three misdemeanor charges of sexual abuse. Ahmed will have to register as a sex offender for life.

Assistant U.S. Attorney Sharon Marcus-Kurn said Ahmed preyed on male patients he had identified as being gay.

"He lured his victims and gained their trust with his fancy Georgetown office and white physician's coat," she said. "His pleasure was momentary, but his effects will be forever with his victims."

In court Friday, four of Ahmed's former patients and one former employee spoke of feeling betrayed after trusting the dentist, only to be sexually assaulted while they were sedated.

One victim recounted to Judge Zoe Bush at the sentencing that while he was attending medical school in Washington, he was assaulted by Ahmed in 2010. "I was mortified at being sexual assaulted by another doctor," he said, adding that Ahmed telephoned him the next day "just to ask me if I was okay."

One victim said he lived in silence even as he watched a growing number of women go public with their stories of sexual assault and harassment nationwide as part of the #MeToo movement.

"I thought no one would believe me. No one believes gay men can be raped," he told the judge.

One person whom Ahmed assaulted in 2014 received a diagnosis of post-traumatic stress disorder and suffered panic attacks, prosecutors said. Some patients, prosecutors said, have not returned to any dental office.

Ahmed sat at a courtroom table next to his attorneys as the victims spoke, covering his face with his right hand.

Ahmed is a husband and father of six whose 3-year-old son died in June in an accidental fall from a window.

Ronald Weiner, a forensic mental-health expert who examined Ahmed after his arrest, said at the sentencing that he believes the former dentist, who said he was sexually assaulted as a child, would not reoffend after therapy.

Walking to the lectern with a cane after recently suffering a heart attack, Ahmed, standing next to his attorney, apologized to his victims, the judge and his family. "I feel the shame," he said. "To err is human, to forgive, divine."