11/13/2014 02:37 EST | Updated 01/13/2015 05:59 EST

Dr. Bob Rishiraj accused over propofol use in case of brain damaged teen

A College of Dental Surgeons in British Columbia hearing is underway into allegations of unprofessional conduct involving a Kamloops dentist, after a teenage patient suffered irreversible brain damage.

The college is investigating allegations Dr.Bob Rishiraj used propofol for deep sedation without proper training.

Propofol is an anaesthetic that has also been linked to the deaths of both Joan Rivers and Michael Jackson.

At Thursday's hearing, a dental assistant who worked with Rishiraj, testified that the 18-year-old patient stopped breathing during oral surgery for the removal of wisdom teeth.

During the procedure, the assistant said, she performed chest compressions and 911 was called. She recalled "bawling her eyes out" and leaving the office after the incident.

Neither the patient nor any of the witnesses can be named due to a publication ban. None of the allegations have been proven in court.