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X-ray Safety

Qualifications to operate dental radiographic equipment in Ontario

Updated February 2023; Originally published in the August/September 2013 issue of Dispatch.

Who can prescribe dental radiographs? 

In a dental office, only a dentist has the authority to prescribe dental radiographs.  

Dentists who hold a valid CT Member Authorization from the College may prescribe dental CT scans at any dental facility that holds a valid dental CT scanner facility permit. More details can be found at: Standards of Practice – Dental CT Scanners (msecnd.net)  

Who can take dental radiographs in Ontario?

The Healing Arts Radiation Protection (HARP) Act sets out the qualifications and requirements for persons operating x-ray machines in dental facilities. The legislation indicates the following persons are permitted to take radiographs in a dental office: 

  1. Dentists who are registered members of the College may take radiographs. Dentists who hold a valid CT Member Authorization from the College may take CT scans at any dental facility with a valid dental CT scanner facility permit, as long as they have received onsite training in the safe operation of the dental CT scanner installed in that facility. (Reference: CT Member Authorization (rcdso.org) and Standards of Practice – Dental CT Scanners (msecnd.net)). 
  2. Dental hygienists who are registered members of the College of Dental Hygienists of Ontario are qualified to operate dental radiographic equipment (except CT scanners) 
  3. Dental assistants/staff who meet HARP qualifications (see below) are qualified to operate dental radiographic equipment (except CT scanners)  
  4. Dental assisting and dental hygiene students are also able to operate dental radiographic equipment (except CT scanners) in teaching clinics at Colleges of Applied Arts and Technology and under the supervision of dentists during field placements in dental offices for approved vocational college programs in dental assisting (level I or II) 
  5. Qualified medical radiation technologists registered with the College of Medical Radiation and Imaging Technologists of Ontario (CMRITO) may take radiographs with dental radiographic equipment. They may also operate dental CT scanners under the onsite supervision of a qualified prescribing dentist. (Reference: CT Member Authorization (rcdso.org) and Standard of Practice for Dental CT Scanners)
  6. Dental students are permitted to operate dental radiographic equipment (except CT scanners) in teaching clinics at Faculties of Dentistry and under the supervision of dentists during rotations which are part of their curriculum requirements.
    1. *Graduate dental students (residents) are permitted to operate a CT scanner in teaching clinics at the Faculties of Dentistry if they are under the supervision of another dentist with CT member authorization.  

What is considered sufficient proof of qualifications for dental assistants/staff to take radiographs in a dental office? 

For dental assistants/staff trained in Ontario:  

Any of the following items are acceptable as proof of qualifications: 

  1. A diploma, certificate or transcript confirming successful completion of a dental assisting course/program. Courses/programs are approved by the Director of X-ray Safety at the Ministry of Health (“HARP-approved course/program”). A list of schools which currently offer HARP-approved courses/programs is available from the X-ray Inspection Service (XRIS) at xris@ontario.ca, OR 
  2. A diploma, certificate or transcript confirming successful completion of a dental assisting course/program that has been approved by the HARP Commission (prior to 2009), OR 
  3. A certificate from the RCDSO confirming successful completion of the x-ray safety update course taken during the December 1983 – December 1986 period; OR 
  4. A “HARP” letter issued by the Director of X-ray Safety  

Note on “HARP” letters:  

XRIS no longer issues HARP letters. Historically, HARP letters were issued to some graduates as an acknowledgement letter indicating that the individual had completed a HARP-approved course/program. These HARP letters will continue to be accepted as proof by XRIS.  XRIS has advised they will not reissue any lost HARP letters. Individuals with lost HARP letters will be required to obtain one of the other applicable documents from the above list.  

The X-ray Inspection Unit (XRIS) of the Performance Improvement and Compliance Branch of the Ontario Ministry of Health and Long-Term Care has a complete and current list of approved programs in dental radiation safety/dental assisting in Ontario. XRIS can be contacted at xris@ontario.ca. 

What about individuals who wish to work as dental assistants and were trained outside of Ontario?  

Individuals with dental training from outside of Ontario are not automatically qualified to operate X-ray machines in Ontario. They will need to meet the same requirements outlined above by successfully completing a HARP-approved course/program.  

Individuals who wish to seek exemptions based on their previous education should inquire with one of the current HARP-approved schools to have their qualifications reviewed for possible exemption. This includes internationally-trained dentists and dental hygienists who are not licensed in Ontario, as well as internationally-trained dental assistants. 

Please note: an NDAEB Certificate does not represent HARP Certification in Ontario. The HARP Certificate is a separate Provincial requirement.