How to Send a CBCT Scan, X-rays and Perio Charts to a Referring Dentist, With a Copyable Periodontal Referral Form

The general dentist's front desk says the CBCT went out yesterday. What reached your office was a bounce notice about message size and a faxed referral that says "scan to follow." By the consult, the doctor is planning from a phone photo of a pano. Everyone knows 3D scans are too big to attach, so referrals fall back on flash drives, mailed discs and screenshots.

The computers and accounts behind every channel are part of dental IT support, and this guide covers the file side of a periodontal referral for the office managers who send and receive them. It sits under the periodontal practice technology guide. You get a file inventory, CBCT size arithmetic, a channel matrix, a copyable referral form and a report-back template. It ends with a setup plan both offices can follow.

What files move between a general dentist, a specialist and the lab?

A periodontal referral usually carries six to nine files: the CBCT study, recent 2D X-rays, a perio chart, photos, a medical history, the referral letter and, for implant cases, an intraoral scan. Later a treatment plan, a surgical guide design and a report-back letter travel too. Each one has its own format and its own size class.

Two rows matter most for the IT plan. The CBCT is the only file that routinely breaks an attachment limit. The perio chart is the file most often missing, because it lives inside the practice software and has to be exported. If your office charts by voice, the export step is covered in the voice perio charting setup guide. Planning-software file types and the computers that open them are in the guide to implant planning software computer requirements.

How big is a CBCT scan?

A CBCT study's raw size follows from its field of view and voxel size: divide each dimension of the field of view by the voxel, multiply the three results, then multiply by 2 bytes. A small 5 × 5 cm scan at 0.2 mm is about 31 MB. A full-arch 16 × 16 cm scan at 0.2 mm is about 1 GB.

The formula is:

size ≈ (FOV width ÷ voxel) × (FOV depth ÷ voxel) × (FOV height ÷ voxel) × 2 bytes

The 2 bytes come from the 16-bit grey value stored for each voxel. Use the same unit for the field of view and the voxel, millimetres for both.

Real exports differ from the arithmetic. Compression, DICOM headers, cropping and the vendor's own voxel settings all change the number. Halving the voxel size multiplies the file by eight, which is why a high-resolution small scan can outweigh a lower-resolution large one.

One vendor's real export sizes

Vatech America publishes its own export table, with and without a bundled 3D viewer. These are one vendor's exports, not a rule for every unit.

Two things stand out. First, every row in Vatech's table is many times larger than any default mailbox limit. Second, bundling the viewer adds about 320–355 MB in each row of Vatech's table. Bundle it only when the receiving office has no way to open DICOM.

Hundreds of files: zip them, and name them with a case ID

A multi-file export is a folder of hundreds of .dcm slices. Zip the folder into one archive, or use your software's single-file export if it has one, so nothing goes missing on the way. Name the folder and the zip with a case ID agreed with the referring office, not the patient's full name. That way a forwarded link or a mis-sent file does not show who the patient is in the file name.

Why won't a CBCT go as an attachment? Mailbox limits, and what to use instead

A CBCT study is usually larger than a mailbox will carry. Microsoft 365 mailboxes default to 35 MB for sending and 36 MB for receiving, and personal Gmail to 25 MB. Most studies are hundreds of megabytes. A 2D X-ray or a perio chart PDF fits as an attachment; a CBCT usually needs a share, a portal or a link.

Figures as printed on Microsoft's Exchange Online limits page and Gmail's attachment help page, checked October 2026.

The receiving side matters as much as the sending side. If the referring office raised its limit to 150 MB but your mailbox still takes 36 MB, the message bounces at your end. A link-style attachment (OneDrive or Google Drive) avoids the size problem, but it turns the message into a file share. File shares have their own setup questions, covered in the channel matrix below.

Whether and how to send patient information by email, and how to turn on encryption in Microsoft 365 or Google Workspace, is covered in our page on email security for dental offices.

Which way should we send referral files? The channel matrix

Pick one primary channel and one fallback with each referring office, and write both down. For most perio referrals the primary is the imaging software's share option or a referral portal. The fallback is a secure file link. Each row below shows what the channel needs from both offices before the first case goes out.

Notes on each row

Row 1. Legend supports the IT environment for DEXIS, Vatech, Carestream (CS Imaging / CS 3D Imaging), Planmeca/Romexis and Dolphin Imaging. The share and export-with-viewer options differ by product and version, so open your imaging vendor's own instructions for the exact steps. One example: Planmeca says its free Romexis Viewer "can be exported and sent together with images from the Romexis® software", and that it is "available for both Mac and Windows and does not need to be installed." Vatech's export table above shows how much a bundled viewer adds to the file. The imaging vendor supports the application; the PCs, network and accounts around it are IT work, described on our dental imaging software support page.

Row 2. "Dental referral software" lands here. Some practice software includes a referral module; standalone platforms exist too. Before signing, ask the vendor whether data is encrypted in transit and at rest, whether it will sign a BAA, and whether the referring office needs a paid account.

Row 3. Free consumer transfer services also sit in this row. Before using one, check three things: does the service offer a BAA, can you set an expiry and revoke the link, and is there an audit trail? If any answer is no, use a plan that does. On the named file-share services, the BAA comes only with certain plans: Box says it signs BAAs with customers "who have an Enterprise, Enterprise Plus, or Enterprise Advanced account", and that the BAA "should be in place between Box and the customer prior to storing any Protected Health Information (PHI) on Box." ShareFile says its HIPAA support "is available only with a ShareFile Premium, ShareFile Enterprise, VDR, or Industry Advantage account", and that customers must also accept its Business Associate Agreement. Check the plan before the first study goes up.

HHS's guidance on cloud computing says a cloud service provider that creates, receives, maintains or transmits ePHI for a practice is a business associate, and that this holds even when the provider stores only encrypted data and does not have the key. It adds that "the conduit exception is limited to transmission-only services for PHI." This is HHS's wording; how it applies to your office is a question for your compliance adviser. Read the full HHS guidance on cloud computing. One example of how a vendor handles this: Dropbox's help centre says "a BAA must be in place before you transfer PHI into your Dropbox account," and that team admins in the US can sign one in the admin console. Proposed changes to the Security Rule are tracked in our post on HIPAA Security Rule updates for dental practices.

Row 5. A disc or USB from another office is opened on one designated PC, scanned first, and imported into your own imaging software. The receiving procedure is in the guide to oral surgery referral intake, and it applies to periodontal offices as well.

Row 6. Fax still carries many referral letters and charts. If the fax line runs on copper, read when the copper phone and fax lines go away before it fails mid-referral.

Not sure which channel each of your referring offices can receive? A Free Dental IT Assessment gives you written findings and prioritized recommendations on your computers, software, network security, backups and performance.

What should a periodontal referral include? A copyable referral-packet form

A periodontal referral should include the patient's identity and insurance, the referring office's contact for the report-back, the doctor's reason and urgency, and a list of every file sent, with its date, format and channel. Copy the form below into your practice software as a referral template. Clinical fields are blank for the doctor.

Your periodontist's own referral form lists what they need clinically; this form covers the files and how they travel. Many practice and university forms are fax PDFs or web forms with an upload box. Either way, these fields keep the packet complete.

Six reasons a referral arrives incomplete

Refer patients to a specialist? General practices can ask for the same Free Dental IT Assessment: written findings and prioritized recommendations on your computers, software, network security, backups and performance.

What should a periodontist send back to the referring dentist?

After the consult, the periodontist's office should send a short report-back letter: patient, date seen, the doctor's summary and plan, who sees the patient next, an updated perio chart, and how any images were shared. Save the template below in your practice software. Every field is a blank label the doctor or front desk fills in.

The IT side of the report-back is small but easy to skip:

• • Save the letter as a template in the practice software so it merges patient details.
• • Attach the exported perio chart from the same screen, not from a desktop folder.
• • Send it by the same channel the referral came in on, so the referring office looks in one place.
• • Log the sent letter in the patient record with the date and channel.

Implant cases: moving the CBCT, scan, plan and guide

An implant referral adds four files to the trip: the intraoral scan, the plan, the guide design and the printed guide. Each step has a file, a size class and a channel. Keep large files in the share or portal you agreed for the CBCT, and send only small files as attachments.

Practice-to-lab sending is a separate workflow with its own file formats and portals. If you print guides in-house, our post on 3D dental printers covers the printer side.

What does the referring dentist need to open a CBCT?

A general dentist can open a CBCT in four ways: the viewer bundled with the export, the imaging vendor's cloud or browser viewer, a third-party browser DICOM viewer, or by importing the study into their own imaging software. Each has a different install, privacy and IT task.

Front-desk PCs are often locked down, so the bundled viewer may not run, and that is a sign the lock-down is working. Put the request through as an IT ticket rather than asking for admin rights. If an import fails or images do not show in the patient chart, see when imaging and the practice software stop talking.

Where should received files go?

Received files belong in the patient's record, not in Downloads.

Storing CBCT studies inside your own office is covered in storing and backing up CBCT studies and the dental backup and disaster recovery checklist. How long to keep records is a question for your compliance adviser or your state dental board.

The one-page setup plan for both offices

Set up referral file sharing once per referring office, not once per case. The plan below takes the general dentist's office and the specialist's office through the same ten steps. Each step names who owns it: the IT owner, the imaging or platform vendor, or the front desk.

Multi-factor sign-in and sharing policy are part of dental cybersecurity. If you are opening a new office, add these steps to the periodontal practice startup technology plan before the referral phone line goes live.

Endodontists and oral surgeons: the same plan applies

The channel matrix and both templates work for any specialist who receives CBCTs and reports back. What changes by specialty is small.

• • Endodontists: studies are often small field of view at fine voxel sizes, so check them against the size table, and the report-back goes to the referring doctor.
• • Oral surgeons: most referrals arrive through the phone line and intake, which the oral surgery referral intake guide covers.
• • Prosthodontists and labs: the main trip is the STL to the lab, covered in the lab guide linked above.

What to ask your IT provider about referral file sharing

Take these questions to whoever runs IT for your office. Written answers tell you whether the channel you picked will hold up. For the IT side of a periodontal practice as a whole, see our IT support for periodontists page.

Which periodontal practices has Legend worked with?

Legend Networking's project pages show the IT work on several periodontal practices. Each card states only what the project page lists. None of them describes a referral-sharing setup. Our dental IT support for periodontists page covers the wider office.

Legend's project pages also feature Gum Specialty Center in Allen, Texas, and Venice Periodontics & Implant Dentistry in Venice, Florida.

The facts below are Legend Networking's own:

• • Practices: Served over 3,500 practices since 2004
• • Experience: 22+ years in dental IT (since 2004)
• • Engineering team: In-house engineers; no outsourced first-level triage
• • Monitoring and helpdesk: 24/7 monitoring; Helpdesk staffed 24/7 at 1-800-794-1588
• • Onsite: Onsite dispatch by appointment across served dental markets; remote-first nationwide
• • Imaging and practice software: Legend supports the IT environment for DEXIS, Vatech, Carestream, Planmeca/Romexis and Dolphin Imaging, and for Dentrix, Eaglesoft, Open Dental and Archy
• • Price: Starting at $360 per month. Hardware procurement, major cabling projects and software licensing are quoted separately.

This guide comes from Ian Lynch, who has 22 years in dental IT and oversees the NOC, onsite dispatch and client technology roadmaps.