# Dental Radiography Positioning and Interpretation in Dogs and Cats


## Key Takeaways

- Diagnostic intraoral dental radiography is critical for detecting subgingival pathology in dogs and cats, with approximately 30% bone loss required for radiographic visualization of periodontitis.
- The parallel technique is preferred for mandibular premolars and molars, while the bisecting angle technique is essential for all other teeth, with foreshortening resulting from excessive vertical angulation and elongation from insufficient angulation.
- Normal radiographic anatomy includes a continuous lamina dura, a uniform periodontal ligament space (0.2-0.4 mm), and an alveolar crest 1-2 mm apical to the cementoenamel junction; misinterpretation of normal landmarks like the mental foramen can lead to false diagnoses.
- Periodontal disease is identified by loss of alveolar crest height, widening of the periodontal ligament space, and furcation exposure, with vertical bone loss creating angular defects along root surfaces.
- Systematic interpretation involves confirming image quality, identifying the tooth, evaluating periodontal structures, assessing root and pulp integrity, and examining surrounding bone for lytic lesions or developmental anomalies.
- Common errors include inadequate root apex visualization, superimposition of adjacent roots, geometric distortions (foreshortening/elongation), and motion blur, necessitating at least two views for suspected pathology and three for feline maxillary fourth premolars.

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Dental radiography is an indispensable diagnostic modality in small animal practice. Without radiographic evaluation, a substantial proportion of oral pathology remains undetected, and treatment decisions are made with incomplete information. This article provides a practical framework for obtaining diagnostic intraoral radiographs in dogs and cats and for interpreting the common radiographic signs of dental disease. It is written for the practicing veterinarian who performs dental procedures in general practice and who seeks a structured approach to positioning, exposure, and image interpretation.

The technical demands of dental radiography differ meaningfully from those of standard skull radiography. The small size of the structures imaged, the superimposition of contralateral dental arches, and the need for fine spatial resolution require dedicated equipment and disciplined technique. Familiarity with positioning methods, normal radiographic anatomy, and the radiographic appearance of pathologic processes is necessary before treatment planning can proceed with confidence [Niemiec's feline dental radiography primer](https://pubmed.ncbi.nlm.nih.gov/25344459/). This article addresses those foundations in sequence, beginning with the physical principles that govern image quality and progressing through positioning technique and interpretive logic.

## At a Glance

| Parameter | Clinical Decision or Fact |
|---|---|
| Indication | Any tooth with suspected pathology, every tooth before and after extraction, all feline patients with oral disease |
| Positioning principle | Parallel technique for mandibular premolars and molars, bisecting angle technique for all other teeth |
| Image receptor placement | Intraoral film or digital sensor placed as parallel to the long axis of the tooth as anatomy permits |
| Tubehead angulation | Determined by bisecting the angle between the tooth long axis and the receptor plane |
| Key normal landmark | Lamina dura, periodontal ligament space, and alveolar crest margin visible around every root |
| First radiographic sign of periodontitis | Loss of alveolar crest height, visible only after approximately 30% bone loss |
| Common artifact | Foreshortening or elongation from incorrect vertical angulation, superimposition from incorrect horizontal angulation |
| Interpretation priority | Evaluate bone level, root integrity, pulp chamber width, and periapical lucency in every image |

## Physical Principles of Dental Radiography

### Image Receptor Options

Two receptor systems are in common use: phosphor plate systems and solid-state digital sensors. Both offer advantages over conventional film, including wider exposure latitude and the ability to adjust contrast and brightness after acquisition. Solid-state sensors provide immediate image display but are rigid and thicker, which can complicate placement in patients with limited oral access. Phosphor plates are flexible and thinner, easing intraoral placement, but require a separate scanning step and are more susceptible to scratching and bending artifacts [Eisner's review of veterinary dental radiography problems](https://pubmed.ncbi.nlm.nih.gov/2134590/). Regardless of receptor type, the physical principles of geometric accuracy remain identical.

### Geometric Principles: Parallel and Bisecting Angle Techniques

Two positioning methods produce geometrically accurate images. The parallel technique places the receptor parallel to the long axis of the tooth and directs the central beam perpendicular to both. This method yields the most accurate representation of root length and periodontal structures and is the preferred technique for mandibular premolars and molars, where the floor of the oral cavity permits flat receptor placement.

The bisecting angle technique is required when the receptor cannot be placed parallel to the tooth long axis, which is the case for most maxillary teeth and all canine teeth. The receptor is placed as close to the tooth as possible, and the tubehead is angled perpendicular to an imaginary line that bisects the angle formed by the tooth long axis and the receptor plane. Correct application of this method produces an image with root lengths that approximate true dimensions. Errors in bisecting angle calculation produce predictable distortions: excessive vertical angulation foreshortens the root, while insufficient angulation elongates it [Niemiec's feline dental radiography primer](https://pubmed.ncbi.nlm.nih.gov/25344459/).

### Exposure Parameters

Dental x-ray units operate at fixed kilovoltage, typically 60 to 70 kVp, with exposure time as the primary variable. Recommended exposure times vary by species, tooth size, receptor type, and unit specifications. Practitioners should establish a technique chart for their specific equipment and adjust based on image quality feedback. Overexposure produces a uniformly dark image with loss of cortical detail, underexposure yields a pale image in which the periodontal ligament space cannot be distinguished from the adjacent lamina dura. Digital receptors tolerate a wider exposure range than film, but gross errors in either direction degrade diagnostic quality.

## Normal Radiographic Anatomy

Interpretation requires a working knowledge of the normal radiographic appearance of the periodontium. The lamina dura appears as a thin, continuous radiopaque line outlining the root socket. The periodontal ligament space is the uniform radiolucent line between the root surface and the lamina dura, measuring approximately 0.2 to 0.4 mm in the dog and cat. The alveolar crest appears as a radiopaque line slightly apical to the cementoenamel junction, normally located 1 to 2 mm apical to that junction in healthy animals. The pulp cavity is radiolucent and relatively wide in young animals, narrowing with age as secondary dentine is deposited. The root apex is closed in mature animals, an open apex indicates an immature tooth.

Normal anatomic structures can mimic pathology. The mental foramen on the mandible, the infraorbital canal on the maxilla, and the nasopalatine foramen may be mistaken for periapical lucencies if the interpreter does not correlate the radiographic finding with the expected tooth position. The torus mandibularis, a bony protuberance on the lingual aspect of the mandible, appears as a radiopacity that can be confused with a neoplastic or reactive lesion when viewed in isolation [Nishida and colleagues' CT study of torus mandibularis morphology](https://pubmed.ncbi.nlm.nih.gov/41874804/). Correlation with the clinical examination and the known location of these landmarks prevents misdiagnosis.

## Radiographic Signs of Periodontal Disease

Periodontal disease is the most common indication for dental radiography in small animal practice. Radiographic changes are not visible until the disease is moderately advanced. Bone loss becomes apparent only after approximately 30% of the mineral content has been lost, which corresponds to stage III periodontitis in the American Veterinary Dental College staging system [Bellows' review of radiographic signs of dental disease](https://pubmed.ncbi.nlm.nih.gov/8210796/). The earliest reliable radiographic sign is loss of alveolar crest height, visible as blunting or irregularity of the crest margin.

Bone loss is classified by pattern. Horizontal bone loss maintains the crest at a relatively uniform level across adjacent teeth, while vertical bone loss produces an angular defect along one root surface. The radiographic appearance of the periodontal ligament space widens in the presence of active disease. Furcation exposure, visible as a radiolucent zone between the roots of multirooted teeth, indicates advanced attachment loss and influences the decision between periodontal therapy and extraction. Radiographic assessment of bone loss severity, furcation involvement, and root morphology is required before a prognosis can be assigned to any periodontally compromised tooth.

## Positioning by Tooth and Arch

The bisecting angle technique is the default for most intraoral views in dogs and cats. Parallel technique is reserved for mandibular premolars and molars where the receptor can sit parallel to the root axis. For maxillary teeth, the hard palate prevents parallel placement, so bisecting angle is mandatory. The clinician must estimate the angle bisecting the long axis of the tooth and the plane of the receptor, then direct the central beam perpendicular to that bisector. Errors in angle estimation produce elongation or foreshortening of the root, both of which obscure periapical pathology.

For the maxillary canine, position the receptor with its long axis along the midline of the hard palate, with the tooth positioned near one edge. The tubehead is directed from a dorsal and slightly rostral approach, with the beam aimed at the angle bisector between the tooth root and the receptor plane. The maxillary fourth premolar and molars require the receptor placed as far caudally as the palatal vault permits, often with the patient's head extended and the tubehead directed from a rostroventral approach. The feline maxillary premolars are smaller and the palatal vault shallower, which makes the bisecting angle steeper and the margin for positioning error narrower.

Mandibular views are generally easier because the receptor can be placed lingual to the teeth and the parallel technique used where root axes permit. For the mandibular canine, the receptor sits lingual to the tooth and the beam is directed from a ventrolateral approach. The mandibular premolars and molars accept a parallel placement with the receptor between the tongue and the lingual cortex. In brachycephalic breeds, the mandibular body is short and the roots are crowded, so the bisecting angle technique may be required even for caudal premolars. In cats, the mandibular first molar root is often divergent, and a slight rostrocaudal angulation of the beam may be needed to separate the roots on the image.

The feline maxillary canine root is long and curves caudally. A single bisecting angle view may not demonstrate the full root length, and a second view with the beam shifted 10 to 15 degrees rostrally is often required to assess the periapical region. Similarly, the mandibular first molar in dogs has two roots that diverge mesially and distally. A straight lateral projection superimposes them, so a slight rostrocaudal tilt separates the roots for individual assessment.

## Receptor Placement and Patient Positioning

The patient is placed in sternal recumbency for maxillary views and in lateral or dorsal recumbency for mandibular views, depending on clinician preference and patient stability. The head is stabilized with a positioning wedge or tape. The receptor is placed intraorally with the active surface facing the tooth of interest. For maxillary views, the receptor is held against the hard palate. For mandibular views, it sits between the tongue and the lingual surface of the mandible. The receptor must be parallel to the long axis of the tooth for parallel technique, or angled to create the bisecting geometry for the bisecting angle technique.

Digital sensors are rigid and cannot be bent, which limits placement in the shallow feline oral cavity. Phosphor plates can be flexed slightly, which helps conform to the palatal vault but introduces a risk of geometric distortion if the plate bends during exposure. The clinician should select the smallest receptor that covers the region of interest. Oversized receptors cause patient discomfort, increase the likelihood of movement, and force the tubehead into awkward angulations that degrade image geometry.

General anesthesia is required for diagnostic dental radiography in dogs and cats. The patient must be intubated, and the cuff inflated and checked, because positioning the receptor and tubehead near the pharynx can displace the tube. The mouth is held open with a speculum, and the tongue is retracted to the contralateral side for mandibular views. Saliva and blood obscure the image if they pool on the receptor, so the area is dried before placement and the receptor is wiped between exposures.

## Exposure Settings and Technique Charts

Exposure parameters depend on the receptor type, the tubehead output, and the thickness of the tissue being penetrated. Digital sensors require substantially lower exposure than film, and phosphor plates require slightly more than sensors. The clinician should establish a technique chart for the specific unit in use, testing each setting on a cadaver skull or a patient under anesthesia and recording the settings that produce diagnostic images.

The maxillary region is denser than the mandibular region because of the palatine bone and the nasal cavity, so maxillary views generally require a higher exposure than mandibular views at the same tooth position. Feline skulls are smaller and less dense than canine skulls, so feline exposures are lower. Brachycephalic breeds have a shorter, wider skull with more bone density over the maxillary roots, and the exposure may need to be increased compared with mesaticephalic breeds. The clinician should compare the density of the image with the expected appearance of enamel, dentine, and pulp and adjust the technique chart accordingly.

Underexposure produces a pale image with poor contrast between enamel and dentine, and periapical lucencies may be missed. Overexposure produces a dark image in which the root apex is lost against the surrounding bone. The pulp cavity should appear as a distinct radiolucent line within the root, and the periodontal ligament space should be visible as a thin radiolucent line between the root and the lamina dura. If these structures are not visible, the exposure or the positioning is incorrect.

## Systematic Image Evaluation

Each radiograph is evaluated in a fixed sequence to avoid missing pathology. The first step is to confirm the image is diagnostic. The tooth or teeth of interest must be fully included, the roots must not be foreshortened or elongated, and the image must be sharp with no motion blur. The orientation marker must be visible and correct. If the image fails any of these checks, it is repeated before the patient is recovered.

The second step is to identify the tooth or teeth imaged. The clinician counts from the midline using the Triadan system and confirms the identification against the clinical examination findings. The third step is to evaluate the periodontal structures. The lamina dura is assessed for continuity, the periodontal ligament space for widening, and the alveolar bone margin for height relative to the cementoenamel junction. Stage III periodontitis is the earliest stage at which radiographic abnormalities become apparent, so a normal radiograph does not exclude early periodontal disease [Bellows, Radiographic signs and diagnosis of dental disease](https://pubmed.ncbi.nlm.nih.gov/8210796/).

The fourth step is to evaluate the root and pulp. The root outline is assessed for resorption, fracture, or external replacement resorption. The pulp cavity is assessed for width, which narrows with age and widens with pulpitis or pulp necrosis. The periapical region is assessed for lucency, which may represent granuloma, cyst, or abscess, and for radiodensity, which may represent sclerotic bone or condensing osteitis [Bellows, Radiographic signs and diagnosis of dental disease](https://pubmed.ncbi.nlm.nih.gov/8210796/).

The fifth step is to evaluate the surrounding bone for changes outside the periodontal structures. Lytic lesions of the jaw may represent neoplasia, and neoplasms can displace or disrupt teeth in the dental arch [Bellows, Radiographic signs and diagnosis of dental disease](https://pubmed.ncbi.nlm.nih.gov/8210796/). The nasal cavity and the mandibular canal are assessed for symmetry and for abnormal soft tissue opacity.

## Common Positioning Errors and Their Recognition

Elongation of the root indicates that the bisecting angle was underestimated, so the central beam was directed too perpendicular to the receptor. Foreshortening indicates the angle was overestimated. Both errors can be corrected by re-estimating the bisector and repeating the exposure. Superimposition of adjacent teeth indicates the beam was not directed along the interproximal spaces. The image should be repeated with the beam angled through the contacts.

A common error in feline maxillary views is placing the receptor too far rostrally, which cuts off the caudal roots of the fourth premolar or the molar. The clinician should confirm the full crown and root of the target tooth are visible before recovering the patient. Another error is using a receptor that is too large for the feline oral cavity, which forces the tubehead into a steep angle and produces severe foreshortening. The smallest receptor available should be used for feline patients [Niemiec, Feline dental radiography and radiology: A primer](https://pubmed.ncbi.nlm.nih.gov/25344459/).

Motion blur is common in patients that are not adequately anesthetised or when the tubehead is bumped during exposure. The image appears uniformly unsharp, and fine structures such as the periodontal ligament space are lost. The exposure is repeated after confirming the patient is stable and the tubehead is secure.

## Documentation and Record Keeping

Each radiograph is labelled with the patient identification, the date, the tooth or region imaged, and the orientation. The images are stored in the patient record, and the interpretation is recorded in the dental chart. The chart should include a description of each finding, the tooth number, and the diagnosis. Serial radiographs are compared with previous studies to assess progression of periodontal disease, endodontic disease, or resorptive lesions.

The following table summarizes the selection of positioning technique by region and the common errors associated with each.

| Region | Preferred technique | Receptor placement | Common error | Correction |
| --- | --- | --- | --- | --- |
| Maxillary premolars and molars | Bisecting angle | Against hard palate | Foreshortening from steep angle | Reduce tubehead angle, re-estimate bisector |
| Maxillary canine | Bisecting angle | Along palatal midline | Root apex cut off caudally | Shift receptor caudally, add rostral angulation |
| Mandibular premolars and molars | Parallel where possible | Lingual to tooth, parallel to root axis | Elongation from shallow angle | Increase tubehead angle toward perpendicular |
| Mandibular canine | Bisecting angle | Lingual to tooth | Superimposition of contralateral canine | Angle beam rostrocaudally to separate |
| Feline maxillary premolars | Bisecting angle | Smallest receptor available | Receptor too large, severe distortion | Use smaller receptor, confirm full root visible |

The record should note the exposure settings used for each view so that repeat studies can be performed with the same technique. If a finding is equivocal, the clinician should state the uncertainty in the record and recommend a repeat study or advanced imaging. Computed tomography may be required when radiography is inconclusive, particularly for complex fractures or suspected neoplasia, and the limitations of radiography should be acknowledged when they apply [Baratt, Dental Radiography and Radiographic Signs of Equine Dental Disease](https://pubmed.ncbi.nlm.nih.gov/33067094/).

## Complications and Failure Modes in Dental Radiography

The most common complication in dental radiography is a non-diagnostic image that leads to missed pathology or inappropriate treatment. Inadequate exposure of the root apex is the most frequent failure, particularly for maxillary premolars and molars where the palatal root diverges from the buccal roots. Detection is straightforward: the apex must be visible with 2 to 3 mm of periapical bone beyond the root tip. If the apex is cut off, the image must be retaken before any endodontic or extraction procedure begins.

Overlapping of adjacent teeth obscures interproximal bone and root surfaces. This occurs when the central ray is not directed through the interproximal spaces, a problem most pronounced in the mandibular premolar region where tooth roots converge. The discriminating check is whether the periodontal ligament spaces of adjacent teeth appear as distinct parallel lines. If they merge or disappear, reposition the tubehead to direct the beam through the contact points.

Foreshortening and elongation remain the most common geometric errors. Foreshortening, where roots appear shorter and wider than actual, results from excessive vertical angulation. Elongation, where roots appear long and blurred, results from insufficient angulation. The corrective action is to adjust the bisecting angle: for each 5 degrees of error, the image distorts by approximately 8 percent of the root length. Digital receptors allow immediate assessment and correction, whereas film-based systems require disciplined technique charts to minimize retakes.

Patient motion produces a characteriztic blurring that is often mistaken for underexposure. The distinguishing feature is that motion blur affects the entire image uniformly, whereas underexposure produces a grainy, low-contrast appearance with visible receptor noise. General anesthesia eliminates this problem in most patients, but heavy sedation with positional restraint may be acceptable for cooperative patients.

| Observation | Likely Cause | Discriminating Check |
|---|---|---|
| Root apex not visible | Insufficient receptor placement or angulation | Confirm 2 to 3 mm of bone beyond apex |
| Adjacent roots overlap | Central ray not through interproximal space | Check for distinct periodontal ligament lines |
| Roots appear short and wide | Excessive vertical angulation (foreshortening) | Compare crown-to-root ratio with clinical length |
| Roots appear long and blurred | Insufficient vertical angulation (elongation) | Assess sharpness of root outline |
| Uniform image blur | Patient motion | Check for sharp vessel or trabecular detail |
| Radiopaque artifact over root | Superimposed anatomy or receptor artifact | Retake with altered horizontal angulation |

## Common Errors by Less Experienced Clinicians

Novice operators frequently misidentify normal anatomic structures as pathology. The mandibular canal appears as a radiolucent band below the premolar and molar roots and can be mistaken for periapical pathology. The key discriminator is that the mandibular canal has a smooth, corticated margin and runs parallel to the ventral mandibular border, whereas periapical lesions are irregular and centerd on the root apex. The nasolacrimal canal and infraorbital canal similarly mimic pathology in the maxilla and require familiarity with normal anatomy before interpretation.

Underexposure is the most common technical error in digital systems because operators compensate for patient size by reducing exposure time instead of adjusting kilovoltage. The result is a noisy image that obscures early periodontal disease. Overexposure produces a washed-out image that hides periapical lucencies. The corrective action is to establish a technique chart based on patient size and tooth region, then verify image quality against known standards before interpretation.

Another frequent error is interpreting a single view as definitive. Dental pathology, particularly root fractures and resorptive lesions, may be visible in only one projection. The standard of care requires at least two views at different angles for any tooth with suspected pathology, and three views for the maxillary fourth premolar where the palatal root is superimposed over the buccal roots in standard projections.

## Limitations of Current Evidence

The evidence base for veterinary dental radiography relies heavily on expert opinion and clinical experience instead of controlled trials. Positioning recommendations derive from human dental radiology adapted to canine and feline anatomy, and the optimal angulation for each tooth is based on geometric principles instead of validated outcome studies. The bisecting angle technique assumes a predictable relationship between receptor, tooth, and beam that may not hold in brachycephalic breeds with distorted dental arches.

Feline dental radiography presents particular challenges. The small size of feline teeth and the thinness of the mandible require higher resolution and lower exposure than canine patients, and the technique has a steeper learning curve. The interpretation of feline resorptive lesions remains an area of active discussion, particularly regarding the distinction between type 1 and type 2 lesions and their implications for extraction versus crown amputation.

Expert opinion differs on the necessity of full-mouth radiographs in every patient. Some authorities recommend full-mouth studies for all dental patients, citing the high prevalence of radiographically silent pathology. Others advocate targeted radiographs based on clinical findings, arguing that full-mouth studies increase anesthesia time and cost without proportional benefit. The evidence does not resolve this disagreement, and practice patterns vary by region and referral setting.

## Referral and Escalation Criteria

Referral to a veterinary dental specialist is indicated when radiographic findings exceed the operator's diagnostic or therapeutic capability. Suspected oral neoplasia, particularly lesions showing aggressive bone lysis with irregular margins, tooth displacement, or pathologic fracture, warrants specialist consultation and biopsy before any extraction is performed. Advanced imaging, including computed tomography, may be required to define tumor margins and plan surgical resection.

Endodontic disease with periapical involvement that requires root canal therapy instead of extraction should be referred to a specialist or practitioner with appropriate training. Similarly, complicated crown-root fractures, root resorption that threatens adjacent teeth, and oronasal fistulae identified radiographically all benefit from specialist assessment.

Laboratory involvement is indicated when radiographic findings suggest systemic disease. Generalized bone density loss, multiple root resorptions, or atypical lucencies may indicate metabolic bone disease, renal secondary hyperparathyroidism, or neoplasia. In these cases, serum biochemistry, hematology, and possibly bone biopsy are appropriate before dental treatment proceeds.

Radiation safety incidents require reporting according to jurisdictional requirements. Accidental exposure of personnel, equipment malfunction, or repeated retakes that exceed institutional dose limits should be documented and reported through the appropriate channels. Professional guidance on radiation safety in veterinary diagnostic imaging is available from the American College of Veterinary Radiology and the American Veterinary Medical Association.

## Frequently Asked Questions

### How do I obtain diagnostic dental radiographs when only standard veterinary X-ray equipment is available?

Standard radiographic equipment can produce usable dental images, but dental X-ray units provide superior quality and greater convenience for patient positioning. With standard equipment, use the smallest focal film distance possible, position the patient in lateral recumbency, and place the receptor intraorally whenever anatomy permits. The bisecting angle technique becomes essential because parallel placement is rarely possible with large tubeheads. Extend the cone or collimator close to the patient to reduce scatter and magnification. Use higher detail screens or non-screen film if available. Accept that some views, particularly caudal maxillary premolars and molars, may be impossible to obtain without a dental unit. Refer those cases or consider CT when the clinical question justifies it. [Problems associated with veterinary dental radiography](https://pubmed.ncbi.nlm.nih.gov/2134590/) describes equipment limitations and positioning adaptations in detail.

### When should I refer a dental radiographic study instead of attempt it in general practice?

Refer when the required view cannot be obtained after two positioning attempts, when the patient cannot be safely positioned without prolonged anesthesia, or when the image quality is insufficient to answer the clinical question. Suspected neoplasia with extensive bone lysis warrants advanced imaging because radiography underestimates tumor margins. Refer also when root resorption, root fracture, or oronasal fistula is suspected but not confirmed radiographically, and when the clinician lacks confidence interpreting the study. The [American College of Veterinary Radiology resources](https://acvr.org/) provide guidance on specialty referral criteria and advanced imaging indications. Early referral reduces repeated anesthetics and delayed treatment.

### How should I explain the need for dental radiographs to a client who declines the procedure?

Explain that dental disease commonly hides below the gingival margin and that clinical examination alone misses a substantial proportion of pathology. Use the analogy of examining only the visible portion of an iceberg. State that treatment decisions, including whether a tooth can be saved or must be extracted, depend on radiographic findings. For feline patients, emphasize that tooth resorption and periapical disease are common and frequently painful. Offer a staged approach: perform the examination and prophylaxis now, and schedule radiographs if the client later approves. Document the declined recommendation clearly in the medical record. The [AVMA practice resources](https://www.avma.org/resources-tools) offer communication guidance for informed consent discussions.

### What are the minimum equipment requirements for a practice starting dental radiography?

A dental X-ray unit with adjustable kVp and mA, size 2 and size 4 digital receptors or film, and a positioning system that supports both parallel and bisecting angle techniques. Digital sensors require a computer and imaging software, phosphor plates require a scanner. Film requires a processor and darkroom. A size 4 receptor is essential for feline full-mouth studies and canine carnassial views. Size 2 receptors suffice for most individual tooth images. Use receptor holders with alignment guides to reduce positioning errors. [Feline dental radiography and radiology: A primer](https://pubmed.ncbi.nlm.nih.gov/25344459/) notes that novices may find film speeds E and F frustrating because of their specific exposure and development requirements, so digital systems are generally recommended for new practices.

### How do dental radiographic interpretation principles differ between dogs and cats?

The fundamental principles of image interpretation are identical, but normal anatomy and common pathology differ. Cats have smaller roots, a more delicate mandibular cortex, and a higher prevalence of tooth resorption and stomatitis-associated bone changes. Feline roots are often imaged with the bisecting angle technique because of limited oral access. Dogs more commonly present with periodontitis-related bone loss and endodontic disease from trauma. The mandibular canal and mental foramina appear more prominent in dogs and can mimic pathology. In both species, compare contralateral teeth and account for normal anatomic variants such as the torus mandibularis, which appears as a radiopaque bony prominence on the lingual mandible and can be mistaken for pathology on panoramic or survey views. [Imaging-based anatomical study of torus mandibularis](https://pubmed.ncbi.nlm.nih.gov/41874804/) documents its variable cortical thickness and radiographic appearance.

### What should I record in the dental chart after obtaining radiographs?

Record the views obtained using a dental numbering system, the image quality assessment, and the radiographic diagnosis for each tooth. Describe bone loss as horizontal or vertical and quantify it as a percentage of root length. Note periapical lucency or sclerosis, root morphology, pulp chamber width relative to normal, and the presence of resorption. Record the technique used, including receptor size and exposure settings, so that follow-up studies are comparable. Store images in the permanent medical record with the same retention standards as other diagnostic images. Note any positioning compromises that limit interpretation. The [MSD Veterinary Manual](https://www.msdvetmanual.com/) provides standard terminology for describing dental pathology that supports consistent record keeping across practitioners.

## Related Clinical & Scientific Guides

* [MRI Monitoring of Brain Tumor Response to Therapy in Dogs](/knowledge/veterinary-medicine/diagnostic-imaging/mri-monitoring-brain-tumor-response-therapy-dogs)
* [Ultrasound-Guided Drainage of Abscesses in Small Animals](/knowledge/veterinary-medicine/diagnostic-imaging/ultrasound-guided-drainage-abscesses-small-animals)
* [Radiographic Monitoring of Total Hip Replacement in Dogs](/knowledge/veterinary-medicine/diagnostic-imaging/radiographic-monitoring-total-hip-replacement-dogs)


## References and Further Reading

- [Feline dental radiography and radiology: A primer.](https://pubmed.ncbi.nlm.nih.gov/25344459/). 2014.
- [Radiographic signs and diagnosis of dental disease.](https://pubmed.ncbi.nlm.nih.gov/8210796/). 1993.
- [Problems associated with veterinary dental radiography.](https://pubmed.ncbi.nlm.nih.gov/2134590/). 1990.
- [Dental Radiography and Radiographic Signs of Equine Dental Disease.](https://pubmed.ncbi.nlm.nih.gov/33067094/). 2020.
- [Imaging-based anatomical study of torus mandibularis: morphological features identified by computed tomography and their correlation with panoramic radiographic appearances.](https://pubmed.ncbi.nlm.nih.gov/41874804/). 2026.
- [A review of equine dental disorders.](https://pubmed.ncbi.nlm.nih.gov/15727909/). 2005.
- [American College of Veterinary Radiology Resources](https://acvr.org/). American College of Veterinary Radiology.
- [MSD Veterinary Manual, Professional Edition](https://www.msdvetmanual.com/). MSD Veterinary Manual.
- [American Veterinary Medical Association Practice Resources](https://www.avma.org/resources-tools). American Veterinary Medical Association.

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- [Echocardiography in Dogs and Cats: Indications and Basic Interpretation](/knowledge/veterinary-medicine/diagnostic-imaging/echocardiography-dogs-cats-indications-basic-interpretation)
- [Thoracic Radiography in Equine Practice: Technique and Interpretation](/knowledge/veterinary-medicine/diagnostic-imaging/thoracic-radiography-equine-practice-technique-interpretation)
- [Systematic Interpretation of Thoracic Radiographs in Dogs and Cats](/knowledge/veterinary-medicine/diagnostic-imaging/systematic-interpretation-thoracic-radiographs-dogs-cats)
- [Recognizing and Correcting Positioning Errors in Veterinary Radiography](/knowledge/veterinary-medicine/diagnostic-imaging/recognizing-correcting-positioning-errors-veterinary-radiography)

> This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.