Your go-to reference for x-ray safety when considering or undergoing orthodontic treatment
X-rays (also called radiographs) are an essential part of accurate diagnosis, treatment planning, and treatment outcomes for orthodontic treatment. In today's post, we'll cover the various types of dental x-rays you may undergo, their common intended uses, and the safety considerations for you or your children.
Types of Dental X-Rays
1) Panoramic Radiograph:
This type of x-ray captures all of the teeth and supporting bone circumferentially and displays these structures in a flattened or "panoramic" view, hence the name! This can best be thought of as a zoomed-out overview of all of the teeth, including any teeth that have not erupted into the mouth (i.e. baby teeth, adult teeth, and wisdom teeth).
Used by: All dentists and most dental specialists
Structures evaluated: Erupted teeth, unerupted teeth, wisdom teeth, tooth root structure, supporting bone, nerve locations, TMJ (jaw joint) anatomy, nasal structures and airway
Orthodontic purposes:
Eruption status or problems of primary teeth ("baby" teeth) and adult teeth
Eruption status and space for wisdom teeth
Tooth root shape and length for risk of root resorption
Supporting bone level
TMJ (jaw joint) symmetry or signs of TMJ arthritis
Nasal airway opening and nasal bone/septum injury
2) Lateral Cephalometric Radiograph:
This type of x-ray captures all of the teeth and supporting bone from a side or lateral view. This can best be thought of as a profile view of the head, neck, jaws, and teeth. Although orthodotic treatment is often offered at the general dentist office or through at-home services (i.e. Smile Direct or Byte), this x-ray is typically only taken at an orthodontist office. If provides a wealth of information that is important for optimal orthodontic diagnosis and treatment.
Used by: Orthodontist and Oral Surgeon
Structures evaluated: Teeth, supporting bone, jaws, facial skeleton, vertebrae, nasal and oral airway
Orthodontic purposes:
Tooth and jaw position
Bite evaluation
Jaw growth and overall bodily growth status
Bone support of the upper and lower front teeth
Openness of nasal and oral airways
3) CBCT Radiograph:
Also called a "3D" x-ray, the full name of this x-ray is a cone beam computer tomography (CBCT) scan. This type of x-ray captures the full three-dimensional information of the area of interest. Depending on the type of machine, it can capture small isolated areas of just a couple of teeth, or it can also capture the entire head and neck. It is a more detailed 3D view of the head, neck, jaws, and/or teeth. Although it's a higher-level x-ray than the types of x-rays mentioned above, it's still not as detailed as a medical or CAT scan x-ray of the head and neck because the areas of interest do not require as much detail.
Used by: Dentist, Orthodontist, Oral Surgeon, Periodontist, Endodontist, Prosthodontist
Structures evaluated: Teeth, bone, jaws, facial skeleton, nerve canals
Orthodontic purposes:
Tooth and jaw position
Position of impacted teeth
Bite evaluation
Jaw surgery planning
Jaw growth and overall bodily growth status
Bone support of the upper and lower front teeth
Openness of nasal and oral airways
4) Bitewing and Periapical Radiographs:
These x-rays are routinely used by general and pediatric dentist to evaluate individual teeth and/or smaller groups of teeth. If you visit your dentist for routine checkups or treatment such as fillings or crowns, you have surely undergone one or both of these types of x-rays. These can be thought of as zoomed-in x-rays to allow for proper diagnosis of cavities, infections, and the status of fillings or crowns. Typically, a bitewing x-ray evaluates teeth for possible cavities, where as a periapical x-ray evaluates for signs of health or infection around the roots of the teeth.
Used by: Dentist, Pediatric Dentist, Periodontist, Endodontist, and Prosthodontist
Structures evaluated: Teeth, Supporting Bone
Orthodontist purposes:
None (usually)
X-Ray Safety Considerations
Are dental x-rays considered safe to undergo when recommended? The short answer is yes, but let's cover the basics about radiation dosages and precautions.
Radiation Background
Whenever any type of x-ray is taken, it involves the use of a specialized form of radiation that is intended to expose certain parts of the body. This exposure of radiation to the intended body structure(s) is necessary to visualize the internal parts of that structure, such as bones or teeth.
In general, dental x-rays require significantly lower levels of radiation to obtain useful images than do medical x-rays. That being said, the amount of radiation used depends on several factors, including but not limited to the following:
Type of x-ray needed
X-ray machine type or age of the machine
Body structure of interest
Level of detail needed
Radiation in Everyday Life
X-rays are not the only things that expose you to radiation. In fact, radiation can be found in a variety of places or situations that you may not realize, including the environment/air, common foods that are high in potassium such as bananas and leafy vegetables, cell phones, power lines, Wi-Fi, modes of transportation such as planes and cars, airport scanners, tanning beds, microwave ovens, and more. Don't feel scared though! There has been much research into how much radiation our bodies can safely handle. The rest of this post will show you exactly where dental x-rays fit into that research.
Dosages Levels of Radiation
Below is a helpful chart to show the relative levels of radiation given off by various x-rays, as well as everyday sources.
Note that the "Sievert" (Sv) is one of the commonly used units of measurement of radiation levels, similar to how we use ounces for fluid levels or inches for measurement. The "Sievert" unit is particularly helpful because it takes into account the amount of radiation produced as well as the type of body structure(s) affected by that type of radiation.
Timing and Frequency of X-rays
As we mentioned, x-rays play an important role in planning and carrying out successful orthodontic treatment. Below is a timeline of when various types of x-rays are often used or required during your orthodontic treatment:
Consultation Visit or Pre-treatment
At this appointment, Dr. C.J. evaluates a ton of information from both x-rays and a clinical evaluation. Depending on the age and dental development stage of the patient, the following x-rays are often required:
Panoramic X-ray
Cephalometric X-ray
CBCT - this may be taken instead of, or in addition to, the first two x-rays to evaluate specific problems that are more complex, such as the location of an impacted tooth.
Mid-treatment or Progress Evaluation
During treatment, a detail-oriented orthodontist should often use one or multiple "progress" x-rays to evalute the movement of teeth so far, which also includes the positioning of the roots of all the teeth to make sure they are properly aligned. Progress x-rays may also be used to evalute growth changes during treatment and/or plan for adjunctive treatments, such as orthognathic surgery. The following x-rays are often taken during the middle to later stages of treatment:
Panoramic X-ray
Cephalometric X-ray
End of Treatment
Lastly, post-treatment x-rays are required to serve as records for the end of orthodontic treatment. In addition, orthodontists like Dr. C.J. will routinely compare the pre-treatment post-treatment x-rays to continuously learn and improve treatment outcomes. This is one of the hallmarks of board-certified orthodontists, who are experts at evaluating and understanding treatment effects or results. The following x-rays are required at the end of active orthodontic treatment:
Panoramic X-ray
Cephalometric X-ray
X-ray Shielding
In the past, you may have worn a shield or "apron" while undergoing dental x-rays. Essentially, these shields are thin, but heavy coverings made of lead covered with a wipeable fabric. The purpose of the lead shield was to reflect or block x-ray beams that "scattered" away from the intended area to be evaluated.
FAQ: Do I or does my child need to wear an x-ray shield or lead apron during dental or orthodontic x-rays?
In modern practice, the short answer is "No", but let's explain that a bit more. Historically (i.e. in the first half of the 1900's), x-ray shielding was recommended because of the relatively primitive technology used to generate x-rays. The shields helped to reduce the radiation dosage received by the patient. Thanks to dramatically improved x-ray technology as well as a profound increase in the understanding of x-ray timing and effects, the radiation dosages received by patients are incredibly lower than they have ever been. In fact, current research has found that x-ray shielding now has negligible effects in reducing radiation dosage during dental x-rays - this is because the current dosage levels are already low enough to not be further reduced by additional shielding.
Source: Benavides et al. (2023) "Patient shielding during dentomaxillofacial radiography: Recommendations from the American Academy of Oral and Maxillofacial Radiology." Journal of the American Dental Association (ADA).
X-rays in Pregnancy
Modern research shows that all dental x-rays are considered safe during pregnancy. The American College of OB/GYN endorses this position and encourages expectant mothers to pursue regular dental exams, x-rays, or treatments as-needed. The one difference is for pregnant patients is shielding -- it is still recommended to utilize shielding of the abdomen and thyroid gland for pregnant women as an addition measure of safety for the mother and developing baby.
If you want more information regarding dental x-rays, feel free to visit the American Dental Association's guide to dental x-rays linked below:
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