Dental scan viewer: DICOM, CT and panoramic in the browser

That is normal: DICOM files often have no extension at all and usually sit inside a folder named something like DICOM, IMAGES, DATA or ST0/SE0. Select such a folder or the whole disc — the tool works out where the scans are from the contents of the files, not from their names. The DICOMDIR table of contents, the viewer program and service files are skipped, and the summary says exactly what was skipped.

When a CT series is loaded, buttons “From above”, “From the front” and “From the side” appear above the sliders. Tap the spot you need on the image — a crosshair appears, and when you switch planes you land at the same point, for example at the root of the same tooth. Slices within a plane are scrolled with the slider, the arrow keys or the mouse wheel with Shift.

Yes: the “Panoramic” button assembles one from the CT along the dental arch. The arch is found automatically — from the teeth, the densest thing in the scan — and if it lands imprecisely, its points can be moved with a finger. A slider changes the layer thickness. Such a panoramic view is more honest than an ordinary one: the magnification is the same along its whole length, and the ruler measures real millimeters. Tap a tooth and choose “Across the arch” to open a slice through it — the very one a dentist uses to assess the bone.

Drag it here as it is. A ZIP, RAR or 7z archive is unpacked right in the browser and the scans in it open; if the archive is password-protected, the tool says so. From a PDF, both the images of the scans and the text of the report are taken — the text can be copied and sent to a second dentist.

Inside DICOM, pixels can be written in several ways. The tool reads all the ones common on clinic discs: uncompressed, JPEG, JPEG Lossless, JPEG-LS, JPEG 2000 and RLE. If a rare variant still turns up — a 12-bit JPEG, say, or an image with a color palette — the tool names it so that it can be explained at the clinic. The ways round it are the program that usually sits on the same disc, or an export in a common format, which most machines can produce.

Probably not. Medical images contain far more brightness levels than a screen can show, and which range to display is set separately — that is called windowing. The file carries a recommended window, but it does not always suit. Press “Auto-adjust”: the tool computes the window from the scan itself, discarding the extreme percentiles that are usually taken up by the black border and the machine’s label.

It is not worth trying to draw conclusions. Caries appears on a scan as a darkening, but so do the shadow of a neighboring tooth, overlap from incorrect positioning, an old filling of certain materials, and simple anatomical variation. A clinician reads the scan together with an examination and knows where to look. The point of this tool is different: to see your own scan, understand which tooth is being discussed, measure a distance and pass the image to a second opinion without sending the whole disc.

Because automatic alignment would be a guess. Panoramic images differ in magnification, tilt and positioning between machines and between patients, and an alignment error of one tooth means a wrong number — exactly the mistake people come here to fix. Manual adjustment takes five seconds and you can see the result with your own eyes.

On tomography slices, yes — the pixel size is recorded and the measurement matches reality, including in the side and front planes. On a panoramic image it is more complicated: a panoramic radiograph is made with a moving slit and has its own magnification, which differs across the jaw, typically by 10–30 percent. So millimeters from a panoramic image are a guide, and for implant planning a dentist measures from the tomography.