A Computed Tomography (CT) scan is a sophisticated imaging technique that utilizes X-rays and computer processing to generate detailed cross-sectional pictures, or “slices,” of the body’s internal structures. This diagnostic tool provides far greater clarity on bones, soft tissues, and blood vessels than conventional X-rays, making it invaluable for diagnosing injury, disease, and planning treatments. When preparing for this procedure, patients are often asked to remove various personal items, leading to a common question about whether removable dental prosthetics, such as dentures, must also be taken out. The answer depends heavily on the specific area of the body being examined and the materials contained within the prosthetic.
When Dentures Must Be Removed
Denture removal is generally required for any CT scan centered on the head, face, neck, or upper chest. This is a standard procedural protocol enforced by the radiology technologist administering the scan. If the field of view includes the oral cavity or surrounding anatomy, the presence of a removable prosthetic necessitates its temporary removal.
This requirement ensures the integrity of the diagnostic images. The technologist typically asks about any removable metal objects, including dentures, eyeglasses, and jewelry, during the preparatory phase. Compliance is necessary before the scan can begin, as leaving dentures in place during a head or neck scan would compromise the results for the interpreting physician.
The Impact of Metal Artifacts on Image Quality
The technical reason behind the removal rule is the phenomenon of “metal artifacts” in CT imaging. Computed tomography relies on the differential absorption of X-ray beams as they pass through different tissue densities. Materials found in many dentures, particularly metallic components, are extremely dense and absorb X-rays far more intensely than bone or soft tissue.
When these dense materials are present, the CT scanner’s reconstruction algorithm is confused by the excessive X-ray absorption and subsequent scatter. This results in the appearance of bright streaks, dark shadows, and geometric distortions on the final image, radiating outward from the location of the metal. These artifacts can completely obscure the surrounding anatomy, such as the jawbone, sinuses, or throat, making it impossible for the radiologist to accurately diagnose conditions in those areas. This distortion effectively renders the scan diagnostically useless for the region of interest, often necessitating a repeat scan.
Nuances Based on Denture Type and Scan Location
Material Composition and Artifact Severity
The necessity of removal often hinges on both the composition of the prosthetic and the anatomical region being scanned. Dentures containing metal, such as partials with chrome-cobalt frameworks, are the primary concern because these materials create the most severe streaking artifacts. While full acrylic dentures without a metal base are less problematic, even some non-metal dental materials can cause minor image disturbances, though not to the same degree as metal.
Conversely, fixed dental work, like permanent bridges, crowns, or implants, cannot be removed and will inevitably cause some degree of localized distortion. Radiologists are aware of this unavoidable metal and use specialized software and techniques to minimize the artifacts and interpret the image despite the distortion.
Scan Location
The location of the scan is another determining factor for the need to remove any prosthetic. If the CT scan is targeting a distant area, such as the abdomen, pelvis, or a limb like the knee, the dentures pose no threat to image quality. The artifacts generated by dental work are highly localized to the head and neck area, so they do not interfere with diagnostic information collected farther down the body.
Ultimately, patients should always inform the technologist about any removable prosthetics, whether metal or acrylic, and follow their specific instructions. The technologist is best equipped to determine if the denture lies within the scan’s field of view.