Open intraoral scanner STL files in your browser
An STL file is a 3D surface mesh: a shell of triangles describing the shape an intraoral scanner captured. Dental laboratories, aligner software and 3D printers all read it. STL stores geometry only, so it carries no colour. Opening one needs no installed software — a browser can read the file and draw the mesh on screen.
Keep every scan on the patient record
DodoDentist keeps intraoral scans, radiographs and CBCT exports against the patient and the tooth, alongside charting, treatment planning, reminders and billing — so the mesh a laboratory sent back is where the next appointment is.
Try DodoDentist freeAn STL file is a list of triangles and nothing else. Each triangle is stored as three corner points and a normal vector, and together the triangles form a shell around the shape the scanner saw. There is no scene, no material, no texture, no layers and no editing history. That is why the format is small, why every piece of dental software reads it, and why it has survived as the exchange format between a scanner, a design package and a printer that share nothing else.
It is also why an STL cannot tell you anything about the patient. A radiograph stores the name, the identifier and the date of birth in the header of every DICOM file; a mesh has no header fields at all. A binary STL has exactly one metadata slot — eighty bytes at the very start, which the exporting software fills with whatever it likes, often its own name and the export date. This page shows that text when it is readable, because it is invisible while you look at the model and still travels with the file.
One thing an STL does not record is units. The coordinates are bare numbers. Intraoral scanners write millimetres and dental software assumes millimetres, but nothing in the file says so, so a model that was rescaled somewhere along the chain opens at the wrong size with no warning at all.
STL exists in two spellings of the same data. A binary STL writes the triangles as raw numbers: eighty bytes of header, a four-byte triangle count, then fifty bytes for every triangle. An ASCII STL writes the same values out as text, opening with the keyword solid, and is several times larger for the same mesh because every coordinate becomes a run of characters. Scanners default to binary; both are correct, and both open here.
The trap is that the keyword does not identify the file. Plenty of exporters write the letters solid into the start of the eighty-byte binary header, so a binary file can begin with exactly the word an ASCII file begins with, and a viewer that tests for the keyword gets it wrong. What settles it is arithmetic: a binary STL is exactly 84 + 50 times its triangle count bytes long, and no other length is possible. This page runs that check, which is why it can name the variant correctly, and why the triangle count shown for a binary file is read straight from the header rather than estimated.
Dental file names are unreliable. 3Shape names its own mesh case files .dcm — the same extension DICOM radiographs use — so a file that looks like an X-ray to any viewer trusting the name is in fact an intraoral scan. CBCT exports go the other way and ship slices with no extension at all. This page reads the leading bytes of whatever you drop and identifies the file from its contents, then tells you when the name disagrees with what is inside. Drop a real radiograph in the DICOM viewer instead
STL cannot carry colour. Not badly, not at reduced quality — there is nowhere in the format to put it. A triangle record has room for three vertices and a normal, and that is the whole specification. An STL export of a full-colour intraoral scan is therefore always grey, and no viewer can recover what the export discarded.
That matters more than it sounds. Colour is what shows inflamed gingiva, staining, the margin where a preparation stops and the line where enamel gives way to dentine. A grey mesh is a plaster model: right for printing and right for a laboratory that needs only the geometry, wrong for anything you intended to look at and judge.
If you need the colour, export a second file alongside the STL. PLY stores a colour value per vertex and stays a single file, which makes it the simplest option. OBJ stores colour as a separate material file and a texture image, so it travels as two or three files that must stay together. Both open on this page as well. Open a PLY scan Open an OBJ scan
| Format | Carries colour | Files per model | Normally used for |
|---|---|---|---|
| STL (binary) | No | One | Printing, aligner stages, laboratory work. The scanner default. |
| STL (ASCII) | No | One | The same triangles written as text. Several times larger. |
| PLY | Yes, one colour per vertex | One | Keeping the colour of a scan in a single file. |
| OBJ | Yes, as a texture image | Two or three | Colour scans where the texture detail matters. The .mtl and image must travel with it. |
| glTF / GLB | Yes | One, or several | Exchange with web and 3D tools outside dentistry. |
| DICOM | Not a mesh at all | One, or hundreds | Radiographs and CBCT volumes. Needs an X-ray viewer, not a model viewer. |
A prescription for a crown or a bridge normally travels as three meshes: the prepared arch, the opposing arch and a bite record. Sent as STL they are pure geometry, which is exactly what the design software needs in order to trace a margin line, build a coping and shape an occlusal surface. Colour is not part of that job, which is why laboratories are content with STL for restorative work and ask for a colour format only when shade or soft tissue is being assessed.
Clear-aligner planning starts from a scan of both arches. The planning software separates the individual teeth, moves them stage by stage, and writes one model per stage — each of them a mesh, each of them destined for a printer. That is why a single aligner case can arrive as a folder of dozens of numbered STL files rather than the two you sent, and why opening one of them shows a single stage rather than the plan.
Printer and mill software consumes STL directly. Before a model prints, the mesh has to be watertight — a closed shell with no holes and no faces wound the wrong way — and a mesh that is not is a common cause of a failed print. Opening a file first will not repair it, but it does tell you that the file is a mesh, how many triangles it holds and that it is neither empty nor truncated, which are the failures worth catching before you commit resin to them.
The mesh itself names nobody. The file name almost always does — laboratories receive files called after a patient every day, and the name is what a mail server, a shared drive and the laboratory inbox all index. The eighty-byte header of a binary STL can carry whatever the exporting software put there as well. Neither is visible while you are looking at the model, which is precisely why both are easy to forget.
Nothing you open on this page is sent anywhere. The file is read in the browser and drawn on a canvas in the same tab; this site has no upload endpoint to send it to, and the mesh reader is only fetched once you actually open a file. Close the tab and nothing of it remains.
Drop it onto this page. The browser reads the file and draws the mesh on screen, with nothing to install and no account to create. Both binary and ASCII STL open, and so do PLY, OBJ and glTF meshes.
Yes, and there is no signup. It exists so a dentist or a laboratory technician can look at a mesh a colleague sent them without hunting for software first.
No. The file is read in the browser and never leaves the computer; this site has no upload endpoint to send it to. The mesh reader itself is only fetched once a file is opened.
Because STL cannot store colour at all. The format holds three vertices and a normal per triangle and has nowhere to put a colour value, so every STL export of a colour scan is grey. Export the scan as PLY, which stores a colour per vertex, or as OBJ with its material and texture files.
They hold the same triangles. Binary writes them as raw numbers and is much the smaller of the two; ASCII writes them out as text and is several times larger for the same mesh. Scanners default to binary. Send whichever your laboratory asks for.
Not necessarily. 3Shape names its own mesh case files .dcm, which is also the extension DICOM radiographs use, so the name alone cannot tell you. This page reads the first bytes of the file and identifies it from its contents, then says which it found.
Yes. PLY, OBJ and glTF all open here too, and unlike STL each of them can carry the colour the scanner captured. Drop one in and the panel under the model names the format that was found.
No. STL coordinates are bare numbers with no unit recorded anywhere in the file. Intraoral scanners and dental software both work in millimetres by convention, but a model rescaled somewhere along the chain will open at the wrong size with no warning, so check dimensions in the design software before printing.