Orthodontic radiographs (x-rays)
Why do we gather radiographs?
Radiographs are an important diagnostic tool in assessing an orthodontic condition and in determining a suitable treatment plan.
The two most common radiographs - although not exclusive - are the panoramic (OPG) and cephalometric views. The OPG provides information about the presence and position of unerupted teeth, the health of the supporting bone around the teeth, jaw joints (TMJ's) sinuses, and the jaw bones (maxilla and mandible).
The lateral cephalogram is a profile x-ray of the skull and soft tissues and is used to assess the relation of the teeth in the jaws, the relation of the jaws to the skull and the relation of the soft tissues to the teeth and jaws. In children, growth predictions can be made and we can also determine the changes that have occured with treatment. In adults, treatment can be predicted with varying degrees of accuracy and results quantified.
OPGThe lateral cephalogram is a profile x-ray of the skull and soft tissues and is used to assess the relation of the teeth in the jaws, the relation of the jaws to the skull and the relation of the soft tissues to the teeth and jaws. In children, growth predictions can be made and we can also determine the changes that have occured with treatment. In adults, treatment can be predicted with varying degrees of accuracy and results quantified.
Computer Aided Tracing
Computer Aided Tracing
Are radiographs harmful?
You may have questions regarding the safety of x-rays used in orthodontic treatment.
The implementation and use of x-ray equipment is strictly monitored by state authorities. This means that the x-ray machine, the room which it is housed in and the staff who are allowed to operate the machine have all received official sanction or training. Additionally, there are comprehensive guidelines to reduce patient and operator exposure. In addition to adhering to these policies, we have the latest digital OPG and lateral cephalogram machine available which reduces radiation exposure to the minimum possible while delivering excellent quality radiographs. As the images are digital, they can be viewed on any computer on our network and transferred electronically to other dentists and specialists.
There is no doubt that inappropriate levels of exposure to radiation are harmful however it should be understood that orthodontic radiographs account for a very small percent of radiation that you will encounter every day. X-rays are naturally occurring and the body is exposed to radiation from natural sources all the time. The average person in Australia receives an effective dose of background radiation approximating 2.5 mSv per year (2500 uSv). The largest source of this background radiation is Radon gas which is emitted from the earth and is present in the atmosphere (42%). Background radiation is also found within buildings and soil (18%), from cosmic sources (14%) and within the food and water we consume (11%). 1% is attributed to the nuclear industry although this is likely to be less in Australia. Interestingly, those who live in Finland receive an average 8 mSv per year, while those who live near shale or granite dominated locales and those who fly regularly receive considerably more background radiation.
The effective radiation dose from an OPG or lateral cephalogram is between 3 and 7 uSv (note this is micro or one thousandth of a mSv). This equates to an equivalent background radiation dose for half to one day. A flight across the Pacific Ocean will provide an effective dose of approximately 0.5 - 1 uSv per hour or 5 - 10 uSv in total.
The moral to the story is that you should not be unduly worried by occasional exposure to orthodontic radiographs unless you are a wine growing (granite belt) Finnish national with a penchant for long distance air travel.
How many x-rays should I expect to have taken?
The OPG and lateral cephalogram are the two most common x-rays gathered at the beginning of treatment. Occasionally other views will be necessary to adequately assess unusual morphology or pathology. The practice of gathering hand-wrist radiographs to determine the skeletal age and thus predict the pubertal growth spurt may be requested however this is in isolated cases only. Patients who return for wisdom teeth assessment will be required to have an updated OPG. Occasionally post treatment OPG and lateral cephalogram will be gathered to determine treatment outcomes. Most patients can expect to have 3 to 5 radiographs over treatment and retention spanning 3 to 4 years.
Radiographs can be forwarded to your dentist and other specialists as electronic or hard copies thus reducing the need for repeated exposures.
What if I refuse to have x-rays?
It is unlikely that treatment will be initiated unless adequate radiographic records are obtained. There is a very real danger to your teeth, jaws and overall well being if treatment is commenced without thorough diagnostic records.
If you do have concerns, please discuss these with your orthodontist.