Dental X-Rays - The How, Why, What, & When Part 3
Happy New Year!! Welcome to 2022 everyone...fingers crossed. At the beginning of every new year, I think about the events that will take place in mine and my family's little world before that year ends. Right now, at the beginning of 2022 I have two children in elementary school, one child in middle school, and one child in high school. By the end of this year my 3rd child will have joined his older brother in middle school, an older brother that will become a teenager, and my oldest child will have her driver's license. Scary. As always, I hope this year. sees my family happy and healthy as I hope it does to all of yours.
As the title states this is the 3rd installment of a deep dive into the world of dental radiographs (X-Rays) for the lay person...aka you, the reader. To prepare for typing out this final article I have gone back and re-read the first two to prevent any redundancies. I have to admit, they were pretty good if I don't say so myself. So, if this is your first time reading my section of 406 Woman it might benefit your understanding by reading the September and November submissions. These can be found @www.406woman.com.
In part one we discussed the most common dental radiograph The Bitewing. In part two we discussed the Peri-Apical radiograph commonly known as the P.A. In this, the 3rd and final discussion on the topic, we will tackle full facial radiographs in two and three dimensions.
The Panoramic Radiograph (Pano]
Panoramic radiography, also called panoramic x-ray, is a two-dimensional (2-D) dental x-ray examina- tion that captures the entire mouth in a single image, including the teeth, upper and lower jaws, surrounding structures and tissues. It provides diagnostic informa- tion of both the bones and the teeth. It is also entirely extra-oral (outside the mouth) save a tiny bite-stick used to position the patient's head correctly. As with the PA discussed last time, the Panoramic radiograph is prescribed every 3 to 5 years to confirm health.
When would a panoramic radiograph be prescribed outside of the recommended interval?
1. To evaluate 3rd molar (aka wisdom teeth) eruption with or without the presence of symptoms. Wisdom teeth are so far back in the jaw that the sensor used for a routine radiograph cannot capture it comfortably, and since wisdom teeth typi- cally come in fours it is standard procedure to evaluate with the Pano. The provide Pano has the 3rd molars circled in red.
2. To evaluate the eruption and to confirm the presence of the permanent teeth in a child. Most of our permanent teeth are forming in our jaw from a very young age (essentially birth). If a parent or dentist has a concern about the development of these teeth a Pano is a good choice as most little children can't tolerate an x-ray sensor simply due to their small- er mouths. The provided Pano is a good example of a child in their "mixed-dentition" phase. I would place this individual at approximately 10 years of age. As you can see, they have three baby teeth remaining in each quadrant with their permanent successors developing underneath.
3. To prepare and plan for more complex full mouth procedures. This can be full mouth extrac- tions in preparing for dentures, or when planning on placing implants. A Pano will show important ana- tomical features in relation to available bone, namely the sinus in the maxillary (upper) jaw, and the Inferior Alveolar Nerve in the mandibular (lower) jaw. The inferior alveolar nerves supply sensation to the lower teeth.
4. When there is a pathological concern.
5. When a traditional sensor is not an option due to comfort, prohibitive anatomy, or pa- thology/swelling.
Cone-Beam Computed Tomography (CBCT)
Cone beam computed tomogra phy (or CBCT) is a medical im- aging technique consisting of X- ray computed tomography where the X-rays are divergent, forming a cone. I can't honestly say I fully understand that last sentence, but what I do know is the CBCT gives us a 3-dimensional image of the mouth. Much like an MRI, it can be sliced in multiple planes and in multiple directions to give the doctor precise information concerning the teeth and jaws.
CBCT utilization in dentistry is relatively new. I would imagine that the majority of dental specialists have a CBCT, while maybe 25 to 35% of general dentists have a CBCT. Of our three Smile Montana locations, two are equipped with CBCT scanners. As these become more accessible and utilized, we might find that the Pano becomes obsolete.
A CBCT is indicated for all of the 5 reasons listed for the Pano, but is primarily utilized for implant planning and other surgical procedures including wisdom teeth, as well as visualizing the extent of certain pathologies.
The Lateral Cephalogram
I won't spend a ton of time on this just know that it is used almost exclusively by Orthodontists but is crucial for orthodontic treatment planning. As the image shows it is simply the skull from the side (aka lateral) and by identifying specific anatomical points an Orthodontist and/or Dentist can determine how to proceed best with treatment. This radiograph allows the doctor to understand the patient's skeletal relationship and how it is affecting tooth and jaw positioning.
In other words, does the patient have an overbite because the upper jaw is growing to fast, or is it due to the lower jaw growing to slow?
This concludes our deep- dive into dental radiogra- phy. I hope you all are as nerdy as me and gleaned some information and en- joyment out of these last three articles. The intention was to help you be informed as to why we take so many x-rays. If I've learned one thing from my 13.5 years in dentistry, it's that radiographs identify issues before they become problems. You and me both would rather fix issues than problems.
Thanks again for tuning in, and I'll see you in two months when I pull back the curtain on our next "to be determined" dental topic.
Read Dental X-Rays - The How, Why, What, & When Part 3 by Dr. John F. Miller, DDS, in 406 Woman magazine.