Dental professionals and support staff encounter imaging errors daily. They can occur at any point from positioning the sensor to interpreting the final image, and they often lead to retakes.
But retakes expose patients to additional radiation and consume more chair time. Over time, repeated errors can disrupt schedules, increase costs, and complicate insurance processing.
By understanding the most common problems and how to resolve them, teams can target their efforts to minimize disruptions, improve workflow, and maintain accuracy and efficiency. In this article, we’ll cover seven major categories of dental radiography errors—and tips for avoiding them.
Let’s take a moment to talk about retake rates.
What Is an Acceptable Retake Rate?
Annual retake rates in dental imaging are tracked as a percentage of total images acquired.
For example, if a practice performs 400 images per month and 48 retake exposures monthly are needed, that equates to a 12% retake rate.
- Optimal: Rates under 5%
- Acceptable: Industry standards suggest a retake rate below 10%
- Problematic: Rates consistently above 15%
1. Missing Apices on Periapicals
Missing apices mean incomplete anatomical coverage on periapical images. They are primarily caused by incorrect X-ray positioning techniques. The sensor may be placed too close to the crowns or not deep enough in the mouth. If the angulation of the X-ray beam is incorrect, the root tip can be cut off, leaving the apex outside the field of view.
Key Positioning Strategies
- Vertical angulation: Align the X-ray beam parallel to the long axis of the tooth to capture the entire root length.
- Sensor placement: Position the receptor deep enough in the mouth to cover all root tips.
- Preview verification: Check images for foreshortening or elongation before finalizing exposure.
For anterior teeth, the sensor is placed high in the palate for upper teeth or deep in the floor of the mouth for lower teeth. For posterior teeth, the sensor is placed slightly away from the teeth and parallel to the long axis, using the bite block for support.
2. Overlapping Contacts on Bitewings
Contact overlap on bitewing radiographs occurs when tooth surfaces appear superimposed, so the spaces between teeth are not clearly visible. This type of dental radiography error makes it difficult to detect interproximal caries (cavities that form between teeth).
Correct X-ray positioning techniques are used to reduce overlap and open the spaces between teeth on the radiograph. The most important technical factor is how the X-ray beam is aimed at the teeth. Aligning the beam perpendicular to the contact points of interest ensures that the spaces between teeth are captured cleanly.
Embrasure alignment serves as a helpful visual cue; line up the open area between two teeth (the embrasure) with the central ray of the X-ray beam.
Positioning Device Options
- Bitewing tabs: Simple, low cost, flexible placement, but offer less precise alignment
- Rinn holders: More consistent results with built-in aiming rings, but are bulkier for patients
- Digital sensor holders: Maximize stability and fit for specific sensor types
Always use a digital preview of the image to verify that contacts are open before finalizing the exposure. Acceptable contact opening means each interproximal space appears as a radiolucent line without overlap from adjacent teeth.
3. Cone Cut and Collimation Misalignment
Cone cutting occurs when a misaligned X-ray beam leaves blank areas on images. Along with collimation misalignment, these problems prevent full visualization of dental structures and can require retaking the image.
The position indicating device (PID) is the part of the X-ray machine that directs the X-ray beam. To avoid cone cuts, line up the center of the PID with the center of the aiming ring on the receptor holder. The PID and the receptor must remain parallel to each other so the X-ray beam covers the full area of the sensor or film.
Pre-Exposure Checklist
- Collimator shape: Match to receptor size (rectangular for digital sensors, round for film).
- Patient size: Select appropriate settings for pediatric vs adult anatomy.
- Beam alignment: Verify the collimator covers entire receptor area without blocking.
Common misalignment patterns include the upper or side edges of the image being cut off. Recognize these patterns early and correct them by adjusting the PID position before exposure.
4. Under- or Over-Exposure Artifacts
Exposure errors in dental radiography occur when the X-ray image is either too light (underexposed) or too dark (overexposed). These artifacts are caused by incorrect selection of exposure variables such as kilovoltage peak (kVp), milliamperage (mA), and exposure time.
Underexposed images appear grainy and lack detail, while overexposed images have excessive darkness and reduced contrast. Both make it difficult to see important anatomical structures. Optimal exposure characteristics require a clear differentiation between enamel, dentin, pulp, and surrounding bone, with visible contrast and density appropriate for the region being imaged.
Exposure settings are adjusted for each patient depending on the thickness of the dental arch and region being imaged. Maxillary molars may require higher kVp or longer exposure time than mandibular anterior teeth due to increased bone density.
Develop standardized protocols by creating exposure charts for each tooth group and sensor type, specifying recommended kVp, mA, and exposure time for different regions and patient sizes.
5. Motion Blur and Unstable Source-to-Receptor Distance
Motion artifacts in dental imaging are caused by movement during exposure. This movement can come from the patient, the sensor, or the X-ray tube head. These artifacts appear as blurriness or double images, which reduce diagnostic accuracy and lower the professional quality of the radiograph. Distance-related blur occurs when the space between the X-ray source and the image receptor is inconsistent or violates equipment guidelines.
Patient Stabilization Techniques
- Headrest positioning: Keep the patient’s head steady and aligned.
- Breath-hold instructions: Use a clear countdown method to minimize movement.
- Bite blocks: Prevent sensor shifting inside the mouth during exposure.
The recommended source-to-receptor distance depends on the imaging system. Intraoral radiographs typically use a distance of 20 to 40 centimeters, whereas panoramic and CBCT systems have specific, fixed distances set by the equipment. Before taking images, check and set the distance according to manufacturer instructions. Position the X-ray tube head close to the patient’s face, verifying the angle and distance to ensure consistent, sharp images.
6. Inadequate Labeling and DICOM Workflow Breakdowns
Accurate labeling is very important because mislabeled or lost images can lead to misdiagnosis, repeat exposures, treatment planning confusion, or insurance claim complications. Incomplete DICOM workflow may also disrupt data transfer between devices or systems.
Current DICOM workflow integration can present challenges, such as compatibility issues among different imaging software, practice management systems, and PACS. Practices may encounter difficulties transferring data seamlessly, leading to workflow disruptions or data silos.
Solutions to these challenges include adopting standardized DICOM protocols, leveraging middleware platforms that bridge disparate systems, and working with vendors, such as Overjet, that offer robust integration support. These strategies help ensure smoother, more reliable data exchange and promote interoperability across dental technologies.
Digital systems use tools like barcode scanners, wristbands, or direct connections to practice management software to confirm patient identity before imaging. A common process is the two-identifier verification, which involves matching at least two unique pieces of patient data before proceeding with image capture.
7. Missed Incidental Findings from Interpretation Gaps
There are legal and ethical responsibilities for dental professionals to conduct comprehensive imaging reviews and to document any significant or potentially harmful findings in the patient record.
A systematic approach can help reduce interpretation gaps. A complete review of every dental image should include periapical areas, periodontal bone levels, caries detection, restoration margins, endodontic status, anatomical landmarks, pathology, implant integrity, and soft tissue evaluation.
Overjet’s dental AI, for example, is trained to highlight subtle pathologies and high-risk findings, which may go unnoticed by human reviewers. When the AI flags possible abnormalities, dental professionals can compare these findings with their clinical assessment and make decisions about documentation and follow-up.
This hybrid process supports thorough review and helps meet documentation standards for incidental findings.