How to use the CBCT viewer in Cympha Studio

The CBCT viewer in Cympha Studio lets you tune the volume, step through the MPR slices and build a panoramic view when you review the scans in a dental case in Cympha.

Audience: Clinicians reviewing CBCT in the browser — orthodontists wanting to see roots in 3D, implant planners checking ridge and sinus anatomy, oral surgeons reviewing a case before consult.

You'll come away knowing: how to load a CBCT series in Studio, tune the volume rendering with HU threshold and opacity, navigate the MPR slice panes, draw an arch curve, switch into panoramic MPR along the arch, and use the orthographic shortcut buttons when no full plan is loaded.

Time required: Around ten minutes start to finish on a familiar CBCT. The CBCT decoding itself takes maybe twenty to sixty seconds depending on volume size and your hardware.

Before you start

You need:

A single CBCT series as a folder of DICOM files. Not a multi-series export, not a zipped .dcm archive — Studio's picker expects the unzipped folder containing the slice files.
A modern desktop browser. CBCT decoding runs entirely in the browser tab; mobile browsers will technically open the volume but the MPR experience is built around mouse + scroll-wheel interaction.
(Optional) An intra-oral scan or facial scan to register against the volume — see How to build a virtual patient in Cympha Studio for the registration workflow. This doc focuses on the volume itself.

Open studio.cympha.com. No account or sign-in is needed — CBCT review is fully open, and the volume is decoded on your own device.

Workspace tip. The top-bar Workspace nav filters Studio's hamburger menu. For CBCT-only review pick 3D Processing or Implant — both expose Open DICOM…. Some narrower workspaces (such as Ceph image processing) hide the DICOM action, so if Open DICOM… doesn't appear in the ☰ menu, switch workspace first.

Step 1 — Open the DICOM folder

Click ☰ (top-left hamburger) → Open DICOM….
The browser opens a folder picker, not a file picker. Choose the folder containing your CBCT series.
Studio decodes the volume locally in the browser — no upload to a server. A progress indicator shows the decode.
When the volume is ready, the MPR slice row appears across the top of the viewport and a 3D rendering of the volume appears in the main view.

Open DICOM… replaces the primary CT volume. It does not clear meshes you've added or a case plan that's loaded — those stay. Only ☰ → Clear scene removes everything.

Cloud implant plan prompt. If implant plans are stored in your Cympha cloud for this CBCT series, Studio may ask whether to import one after the DICOM finishes loading. If you're only reviewing the volume, dismiss it and continue.

Step 2 — Open the View tools panel

Once CBCT is loaded, a small floating dock appears on the left side of the viewport with two icons:

A rendering icon — opens the View tools panel (CT volume controls, arch curve, MPR mode, HU threshold).
An Implant icon — opens the Implant tools panel (for implant planning; out of scope for this doc).

Click the rendering icon to open View tools. The panel is draggable — grab the gray handle at the top to move it out of the way.

Step 3 — Tune the volume rendering

In the CT volume section of View tools:

Opacity (0–1). How solid voxels appear above the HU threshold. Start around 0.8. Lower it to see through dense bone; raise it to make the volume more opaque.
HU threshold. A slider running roughly −1024 to 2048 HU. Voxels above the threshold contribute strongly to the displayed volume; voxels below are progressively transparent. For separating bone and teeth from soft tissue, a threshold somewhere between 200 and 500 HU works for most CBCTs. Drop it lower (e.g., −300 HU) if you want soft-tissue surface for facial scan alignment.
Volume only (3D). A toggle that hides all meshes in the main 3D view so only the volume draws. Useful for diagnostic confirmation — if you suspect an artifact is actually coming from an overlapping mesh rather than the volume itself, toggle this on. MPR overlays may still show meshes.

What the threshold actually controls. It's the lower bound of which voxels contribute to the rendered surface — not contrast. To adjust contrast on a slice, left-drag on the CT background of a slice pane (see Step 5 below).

Step 4 — Navigate the MPR slice panes

The MPR row at the top of the viewport shows three reformatted views by default:

Axial (top-down)
Sagittal (side, perpendicular to the midline)
Coronal (front-back)

These slice views are interactive:

Middle-drag in a slice pane to pan.
Right-drag to zoom.
Left-drag on the CT background (not on a mesh or gizmo) to adjust window / level — i.e., contrast and brightness for that slice. On the axial pane this is deferred while the arch curve tool is active so it doesn't conflict with curve picking.
Slice panes can show mesh overlays when relevant — e.g., a placed implant shows as a silhouette across MPR slices; a registered arch can be set to show via Show in 2D on its right-click menu.

In the View tools panel, the MPR mode section has segmented buttons:

Regular — axial / sagittal / coronal in patient space. The default.
Pano — panoramic MPR along the arch (only enabled after you draw the arch curve — see Step 6).
Gizmo — slices align to the positioning gizmo, enabled only while model positioning is active (e.g., after double-clicking a mesh).

Step 5 — Use the orthographic shortcut buttons (CT-only)

If you've loaded a CBCT without a plan (.gvw) layered on top, a small CT-only orthographic toolbar appears at the top-center of the viewport with three quick framing buttons:

Front
Patient right (the patient's right side, which appears on the viewer's left)
Patient left

These reframe the main 3D view orthographically — useful for cephalometric-style profile and frontal views when you don't have an ortho plan loaded. Once a .gvw case is loaded, the arch toolbar takes over with Both / Upper / Lower jaw plus front and lateral presets.

Step 6 — Draw an arch curve

The arch curve is the prerequisite for panoramic MPR. It's a 2D polyline on the axial slice that defines the dental arch path.

In the View tools panel, turn Arch curve on.
Move your pointer to the axial MPR pane. The arch curve tool only takes input there.
Left-click to add points on the axial slice plane. (These are not HU picks — they're 2D points on the plane.) Place six to ten points roughly following the buccal-side curve of the maxillary arch, starting from one second molar and ending at the contralateral second molar.
Right-click when you have at least two points to finish.
Drag handles on the placed curve to refine. The curve persists until you load a new CBCT (a new CT load clears it) or turn the tool off (turning off hides it but keeps the geometry).

Once the curve is complete, the Pano button in MPR mode becomes enabled.

Step 7 — Switch to panoramic MPR

In the MPR mode segmented buttons, click Pano.
The MPR slice row reformats — instead of axial / sagittal / coronal, you see a panoramic reformation along the arch curve plus cross-sectional slices perpendicular to it.
Use this layout to inspect the arch in the same "unfolded" view a traditional OPG presents — but at any HU threshold and with cross-section panes that show buccal-lingual width at each point along the curve.

Switch back to Regular at any time. The arch curve stays drawn; you can flip between Regular and Pano freely.

What success looks like

The 3D rendering shows bone and dentition cleanly separated from soft tissue at your chosen HU threshold.
Axial / sagittal / coronal MPR panes scroll smoothly and respond to middle-drag pan, right-drag zoom, and left-drag window-level adjustments.
The arch curve traces the buccal side of the maxillary arch from second molar to second molar.
Panoramic MPR (after switching to Pano mode) shows the arch unfolded along the curve with cross-section panes perpendicular to it.

Capturing what you found

Once you've found the view that tells the clinical story, click the camera icon on the top toolbar (Screen capture). With the CBCT layout active the capture is a single PNG that stitches the MPR slice row and the main 3D view as they appear on screen. Studio prompts for an optional comment; the filename is timestamped (MMYYYYDDHHmm.png). The capture lands in the Media gallery (pictures icon on the top toolbar) and travels with the project if you save as .cyp.

Troubleshooting

The DICOM folder picker says it didn't find any DICOM files. The folder you picked is probably one level too high — you may have selected a patient-level folder containing several study subfolders, or a study folder containing multiple series. Drill down until you're at the folder that contains the actual slice files (often hundreds of them with no extension or with .dcm) and pick that.

Volume renders but it looks like a solid white blob. HU threshold is too low (almost everything contributes) or opacity is too high. Raise the threshold to 200–500 HU and drop opacity to 0.6–0.8.

Volume renders but I can barely see anything. HU threshold is too high (only the densest voxels contribute). Drop it.

Pano mode is greyed out. You haven't drawn the arch curve yet, or you turned the tool off before placing at least two points. Turn Arch curve back on and place points on the axial pane, then right-click to finish.

MPR slices show a registered arch mesh and I want to hide it. Right-click the mesh in the main 3D view and choose Hide in 2D (it's a toggle — Show in 2D turns it back on).

Left-drag on the axial pane isn't adjusting contrast. The arch curve tool is active and left-clicks are being captured as curve picks. Turn the arch curve tool off in View tools, then left-drag works for window-level.

I want to load a different CBCT without losing my mesh registrations. ☰ → Open DICOM… replaces only the primary CT volume — meshes and case plans stay. To start completely fresh, ☰ → Clear scene.