Positioning for Veterinary Dental Radiography

Many disease processes may go undiagnosed without radiography, which provides a useful diagnostic and monitoring tool. Radiography also allows us to plan our extractions or other treatments more carefully.

We have produced a comprehensive guide to dental positioning but here is a handy overview of what you should be aiming to achieve, especially if you’re using a handheld generator.

Required views for Veterinary X-rays

A full mouth series consists of rostral maxillary and mandibular views, right and left maxillary views, and right and left mandibular views.

The rostral maxillary and mandibular views should include the canine teeth.

Maxillary canine teeth are best imaged in separate oblique views to prevent superimposition of the first and second premolars upon the canine tooth roots.

In addition, of course, you may wish to take additional views for specific suspected or confirmed dental abnormalities.

A portable handheld X-ray generator is a great asset to aid you in getting the full set of views, as it gives full flexibility in positioning the tube head.

However, care must be taken to avoid inadvertent radiation exposure, and all local rules for radiography must of course be followed.

Positioning the dog or cat

When placing the sensor in the patient’s mouth, care needs to be taken so that it is not damaged, particularly with more flimsy films or sensors.

This may mean using positioning aids like small rubber-coated dental wedges, modeling clay placed in a plastic bag, or disposable gauze sponges/paper towel sheets.

A towel under the patient’s neck will also help to keep them straight during radiography. The tongue can lie between the sensor/film and the teeth in cats and small dogs, the soft tissue opacity will not interfere with image production.

When taking radiographs, you will need to bear in mind the position of the skull, the placement of the sensor/film, and the position of the tube head.

Broadly speaking, the two most common positioning techniques are the parallel technique and bisecting angles.

The parallel technique is used for the caudal mandibular premolars and molars. The bisecting angle technique is used for all the maxillary teeth and the rostral mandibular teeth.

Parallel technique

Place the patient in lateral recumbency with the relevant side facing upwards. The film/sensor will be placed intraorally on the lingual surface of the teeth. Use a film/sensor positioning aid as necessary to keep the film/sensor in place and as parallel as possible to the tooth of interest.

The film/sensor must cover the entire area of interest, from crown to root. The tube head or x-ray machine is set at a 90-degree angle (perpendicular to the film) to take the image.

Bisecting angle technique

The parallel technique has limited use, and so bisecting angles must be used to get the full set of views. The theory behind this is that the correct angle stops image distortion.

If the x-ray beam is too parallel to the sensor/film, it will make the image elongated (like a low setting sun casting long shadows).

If the image produced is abnormally short, then the beam has been made too perpendicular to the sensor/film (like a high sun at noon making short shadows).

The right angle between the two of these will create an image that is a true representation of the patient’s dental anatomy.  

When obtaining views of the maxillary teeth the patient is placed in sternal recumbency and when the mandibular teeth are imaged the patient is usually in dorsal recumbency.

The sensor/film needs to be intraoral, placed in the area of interest with the patient biting on it.

You will then need to imagine a line running parallel to the sensor film and another that is parallel to the tooth (crown to root). Where these lines intersect, they will form an angle, which you will then need to divide in half. Aim the primary beam perpendicular to this imaginary line, keeping it centered over the tooth of interest.

This should produce a true image of the tooth at the correct height and width.

Tips for imaging specific teeth

Rostral mandibular incisors and canine teeth.

Place the patient in dorsal recumbency and make sure that the palate is parallel to the table. Put the sensor/film between the teeth and tongue using a positioning aid.

Position the tube head 90 degrees, perpendicular to the sensor. In small and medium dogs, it is possible to get the canines in the same image as the incisors. For large dogs, it might be necessary to move the sensor caudally to capture all the roots.

Rostral mandibular premolars

The patient is placed in dorsal recumbency with the skull parallel to the table. The sensor/film will be parallel to the table in the bite between the maxillary and mandibular premolars.

The tube head is aimed perpendicular to the bisecting angle line and centered over the premolars of interest.

Caudal right or left mandibular teeth 

The cat or dog is in lateral recumbency with the side of interest facing upwards, ensuring the skull is parallel to the table.

The sensor/film should be intraoral on the lingual side of the tooth of interest. The sensor/film can be orientated in portrait or landscape. Aim the tube head perpendicular to the tooth of interest and sensor or film.

Rostral maxillary incisors and canine teeth 

The patient needs to be in sternal recumbency with the skull parallel to the table. The film/sensor is placed between the maxillary and mandibular incisors with the help of a positioning aid to hold it in place.

The bisecting angle line is determined with the tube head perpendicular to it centering over the incisors. A 20–30-degree angle is often used which helps prevent superimposition of the maxillary first and second premolars.

Oblique views of the maxillary canine teeth 

With the patient in sternal recumbency, position the skull with padding to ensure it is parallel to the floor. The film/sensor is placed intraorally and caudally towards the opposite arcade. This helps to get the root apex in the shot. You may need a positioning aid to keep it in place.

The tube head is aimed perpendicular to the bisecting angle from a rostrolateral approach (centered over the canine tooth). The tube head should be at a 45-degree angle to the sensor/film, ensuring the sensor/film is large enough to capture the crown and the root.

Right or left maxillary premolars 

The patient should be in sternal recumbency with the sensor film placed beneath the maxillary teeth (so that the patient is biting the sensor/film). Positioning devices might be needed to make sure the sensor/film is kept parallel to the table.

The bisecting angle should be determined with the tube head aimed perpendicular to it. In dogs, the tube head is at a 30-45-degree angle, but cats require a steeper angle of 20-30 degrees due to their zygomatic arch.

Teeth with three roots may require a second view to assess their mesial roots, which can be achieved by moving the tube head rostrally while keeping the bisecting angle the same.

Summary

Hopefully, this guide gives you a few pointers when getting started with dental radiography.

One final parting tip that may be of help is if the image is distorted, check the beam angle. If the image is normal but not all areas of interest are visible, check the plate position.

Veterinary Dental Care with Digital Radiographic Imaging

Elevating Veterinary Dentistry: The Power of Digital Radiographic Imaging

Dental radiography is considered an essential part of human dentistry to aid diagnosis and treatment of dental disorders. The veterinary world is catching up rapidly and dental radiography is fast becoming the standard of care for our veterinary patients.

The production of high-quality dental radiographs requires a number of specific pieces of equipment. First, specific dental X-ray plates should generally be used.

These are small and specifically designed to fit within the oral cavity, minimizing the superimposition of structures within the skull and simplifying radiographic positioning.

They come in a range of sizes from 0 to 4, with size 4 being the largest. Sizes 2 and 4 are the most commonly used. Secondly, a specific dental X-ray generator, either handheld or wall mounted, allows accurate and easy positioning for the various views required.

Traditional analog radiography uses X-ray films with an intensifying screen, set within a light-proof cassette.  After exposure to an X-ray beam, this film is then processed using either manual or automatic techniques to provide a high-quality diagnostic image.

The use of digital imaging systems first introduced in the early 2000s  has revolutionized dental radiography and has many advantages over older analog systems.

There are two types of digital X-ray set-up - Digital Radiography (DR) and Computed Radiography (CR). DR, or direct, systems use a solid-state sensor plate in place of an X-ray film.

This is linked directly to a computer via either a wire or wirelessly via Bluetooth. CR, or semidirect, systems use a photo-stimulative phosphor (PSP) plate which stores the X-ray exposure.

These are then scanned and translated into a digital image on a computer. Both have advantages and disadvantages, but DR systems are most commonly used in dental radiography systems and are generally accepted as superior.

The advantages of digital dental radiography 

While there are many advantages, the most notable include:

• Speed - DR systems will produce an almost instant image  and the sensor can be left in place making any repositioning for repeat exposures quicker and easier

• Reduced number of exposures - Digital radiography systems can adjust for suboptimal exposure settings, meaning repeat exposures due to faults are less likely

• Ability to manipulate and magnify images - This allows easier viewing and interpretation of radiographs, picking up more subtle pathologies as the images are more easily interpreted

• No degradation over time if stored correctly 

• No requirement for toxic developing and fixing chemicals

• Less space required 

• Access to telemedicine services

• Lower exposure settings - reducing radiation doses to patients and personnel by an estimated 50-80%

Initial problems were reported with reduced image detail compared with analog films, however, these have now long since been resolved.

Another commonly reported disadvantage of digital radiography set-up is that initial costs are somewhat higher than analog systems.

This is certainly true, however, it has been estimated that in a busy veterinary clinic, it would take less than a year to make up for these costs thanks to significantly lower running costs. Recent cost-benefit analyses have shown the investment is worthwhile.

Full-mouth dental radiographs

There are demonstrated benefits of full mouth X-rays as standard for all new patients, or where a clinical condition has significantly changed. 

It has been suggested that around 40% more pathology will be detected compared with clinical examination alone. 

Radiographs are much more sensitive to detecting periodontal pockets that may be missed by probing alone. They also allow assessment of the thickness and quality of the surrounding bone, reducing the risk of iatrogenic fracture if extractions are attempted, especially in small breed dogs.

Dental radiographs can detect any unusual anatomy such as a curved root that may make extractions more difficult, and post-extraction radiographs can be used to check that no root fragments are remaining.

Especially in cats

Dental radiography is essential when assessing feline mouths where resorptive lesions are present.  Without it, it is impossible to differentiate Type 1 lesions that require complete extraction from Type 2 lesions that are better treated with crown amputations.

Diagnosing the lesion type before treatment improves patient outcomes and reduces procedure times. Deciduous teeth, in both cats and dogs, which may have undergone partial resorption can also be properly assessed.

Dental radiographs are useful when assessing fractured or worn teeth for subtle evidence of infection.  They are vital in helping to determine whether “missing teeth” are truly missing, fractured crowns with roots remaining or impacted teeth that may lead to serious complications such as dentigerous cysts.

They can also be used to help assess oral masses.

How to make the best use of your dental X-ray system

To make the best use of a dental X-ray system there are a few important considerations;

• Correct exposures should be used for different-sized patients and teeth. Some machines will have settings for different teeth programmed in others, others will require the use of a manual exposure chart.

• Dental X-ray plates or sensors and correct plate sizes should be used to minimize exposures and allow easier positioning

• Good radiation safety should be adhered to at all times following ALARA (as low as reasonably achievable) guidelines

• The use of a specific dental X-ray generator is recommended to allow easier and more accurate positioning

• Correct radiographic techniques should be utilized - generally, images should be obtained using either a parallel or bisecting angle technique, depending on the teeth and species being imaged.  For cats, a near parallel (intra- or extraoral) will be required for maxillary cheek teeth.

• Standard views should be obtained for full-mouth radiographs

• Dental radiographs should be performed under general anesthesia

• All radiographs should be assessed to ensure they are of diagnostic quality

• Good training of personnel is vital for both positioning and radiographic interpretation

Digital dental radiography is rapidly emerging as an essential tooth in modern veterinary practice

The whole team should be educated on its benefits to both pets and their owners.  Digital radiographic imaging allows early detection of dental disease, simplifies treatment, and improves patient outcomes enhancing veterinary dental care, as well as providing an additional income stream for veterinary businesses.

https://newvetequipment.com/dental-xray-equipment

References:

[1] Niemiec, B. A., Gawor, J., & Viadimír, J. (2017). Practical Veterinary Dental radiography. In CRC Press eBooks. https://doi.org/10.1201/b20288

[2] Niemiec, B. A., & Wright, M. (2011). Digital Dental Radiology. Clinician’s Brief., https://www.cliniciansbrief.com/article/digital-dental-radiology . Accessed 02/08/2023

[3] Bailey, M. (2021). Veterinary dental radiology – an overview. Royal Canin - VetFocus. https://vetfocus.royalcanin.com/en/scientific/veterinary-dental-radiology-an-overview . Accessed 02/08/2023

[4] Haws IJ. The evolution of oral radiography in veterinary medicine. Can Vet J. 2010 Aug;51(8):899-901.

[5] Van Der Stelt, P. F. (2005). Filmless imaging: The uses of digital radiography in dental practice. The Journal of the American Dental Association, 136(10), 1379–1387

[6] DuPont GA. Radiographic evaluation and treatment of feline dental resorptive lesions. Vet Clin North Am Small Anim Pract 2005;943-962.

[7] Niemiec, B. A. (2015). The importance of dental radiography. Today’s Veterinary Practice. https://todaysveterinarypractice.com/dentistry/dental-radiography-series-the-importance-of-dental-radiography/ Accessed 02/08/2023

[8]  Niemiec, B. A. (2015). Dental Radiology Series: Techniques for Intraoral Radiology. Today’s Veterinary Practice. https://todaysveterinarypractice.com/dentistry/practical-dentistry-dental-radiology-series-techniques-for-intraoral-radiology/ Accessed 02/08/2023

The RAY98(P) Vet Dental X-Ray Generator from XRD Dental

Dental radiographs are considered standard of care by many veterinary dentists, to be included as part of a dental procedure in dogs and cats. That’s because, without x-rays, it’s not possible to see the “whole picture” of what’s going on below the gumline. 

While this is not an exhaustive list, common scenarios where dental x-rays are valuable include pre-and post-views of dental extractions to ensure the entire root tip was removed, differentiating between different types of FORLs, and discovering dentigerous cysts or other issues when there are teeth that are missing or have not erupted as expected. In all of these scenarios, dental radiographs can help determine the best course of treatment and confirm that treatment was done successfully. 

Veterinarians have many choices when it comes to purchasing a dental x-ray system, including the generator, plate/sensor/film, and software. Today, we’ll be evaluating the features of the RAY98(P) Portable Vet Dental X-Ray Generator from XRD Dental.

What Are the Key Features of the RAY98(P) Portable Vet Dental X-Ray Generator?

XRD Dental notes the following features on this model…

• High-frequency technology. Speaking generally about high-frequency technology, this means that a generator produces a beam with a fast waveform and high penetration power, for consistent, high-quality images. Thanks to the narrowing of the x-ray beam spectrum and the ability to use shorter exposure times, high frequency can also mean a lower dose of radiation to patients (and potentially, staff) and less chance of motion artifact. The technology also allows for smaller, more compact machines.

• Portability. Veterinarians and practice managers must decide which type of generator works best for their hospital’s needs. There are cart, wall-mounted, and portable options. Cart and wall-mounted generators offer the advantages of putting more space between the unit and the operator, no risk of running out of battery life, and no need for the unit to be handheld (and thus no arm fatigue/shake, and no risk of damaging the unit by dropping it). Portable units may be preferred in practices with limited space, or in mobile practices. Some clinics may even have more than one type of generator.

• Long battery life. The company doesn’t cite the number of hours the battery is expected to last but does claim that the machine can produce hundreds of exposures with one charge. An automatic shutoff after eight minutes of inactivity helps to conserve battery life.

• Compact size for ease of use. XRD dental specifies that the generator weighs just 3.75 pounds and can be operated with one hand.

• Compatibility with other components. The RAY98(P) is compatible with film, PSP plates, and digital sensors.

• Technical specifications are as follows for the RAY98(P) portable vet dental x-ray generator:

  • Settings of 70kV and 2mA, with the ability to adjust exposure time from 0.04-1.00 seconds.

  • A lighted display with four function keys.

  • 0.4mm focal spot.

  • CANON technology for the x-ray tube.

Purchasing Considerations

Every veterinary practice has different needs based on how busy they are, how many dental procedures they perform, practice style, budget, and other factors. 

Consider whether you need all components, including a generator, plate/sensor, software, or anything else to make your dental radiographs run smoothly, or if you only need to purchase or upgrade one component.

When looking into costs, consider not only the price of the equipment, but also whether warranties are available, how much service costs if there is an issue (and how quickly you could expect to be up and running again in the event of a repair), software upgrades, and any other long-term costs. Ask your sales representative to refer you to other practitioners in your area for questions about how the equipment is working for them in real life.

Taking all these factors into consideration will help determine which type of dental x-ray equipment is best for your individual practice.

Editor’s Note:

For a GREAT DEAL, check out our New Dental X-Ray Equipment Package. It includes:

• Your choice of the generator (choose the RAY98(P), or a different unit if you prefer).

• An intraoral sensor.

• E-Z Dent software and laptop.

• 2-year warranty on hardware and software.

All of this is available for just $12,995, or a convenient monthly price of just $195 so you can earn a profit on your investment right away. This offers significant savings over other popular brands, with a machine that produces great images!

Written by: Dr. Tammy Powell, DVM