Key takeaways
- A panoramic unit only renders sharply the anatomy inside a curved zone called the focal trough. Anything in front of it, behind it, or tilted through it distorts.
- Most bad pans come from positioning: head tipped up or down, patient too far forward or back, head rotated or tilted, tongue off the palate, or slumped posture. Each has a recognizable look.
- Remove metal objects and do not use thyroid collars during pans; the 2024 ADA panel report says thyroid shielding is no longer recommended, and collars block the beam in panoramic imaging. Follow your state's rule if it differs.
- Film units can be converted to digital with retrofit sensors or extraoral phosphor plates, but a used digital unit is often the cleaner path. Price the whole conversion first.
- Consistently distorted images with good positioning point to alignment or calibration, which is technician work. So is any mechanical, electrical, or radiation-related repair.
A panoramic unit takes one image of both jaws, the teeth, the sinuses, and the temporomandibular joints by rotating an x-ray source and a receptor around the patient's head. It is one of the most useful images in general dentistry, and one of the easiest to take badly. This guide explains how the unit forms an image, how to position patients and read errors, how to run and maintain the unit, and what to know about digital conversions and cephalometric arms. For the purchase side and regulatory steps, see our panoramic buying guide and x-ray registration and inspection guide.
What a panoramic unit does and how it works
During a pan, the tubehead and receptor rotate around the patient on opposite sides of the head. A narrow vertical slit beam passes through the jaws, and the rotation center moves during the scan so that the sharp zone follows the curve of the dental arch. Anatomy inside that curved zone, the focal trough, is reproduced sharply. Anatomy outside it blurs and changes size: structures too close to the receptor look narrow, and structures too close to the tube look wide.
The focal trough is narrow in the front of the mouth and wider in the back. That is why small errors in forward or backward position hit the incisors hardest. Some units offer multiple or adjustable troughs, and some let the operator shift the trough forward or back after seeing an image. Digital units capture the image on a sensor in the rotating arm; film units use a cassette carried around the head.
Parts you should know
- Column and carriage: the vertical column raises and lowers the rotating assembly to match patient height.
- Rotating arm (C-arm): carries the tubehead on one side and the receptor on the other.
- Bite block and chin rest: set the front-to-back position of the incisors in the trough.
- Temple supports or head holders: stop rotation and tilt during the scan.
- Positioning lights: laser or light lines for the midsagittal plane, the Frankfort horizontal plane, and the canine or trough line.
- Control panel and workstation: program selection (adult, child, segmented, TMJ, sinus), patient size, and exposure.
- Cephalometric arm (optional): an extension with its own receptor and ear rods for lateral and PA ceph images.
Which type does your practice need?
| Type | What it does | Best for | Trade-offs |
|---|---|---|---|
| 2D digital pan | Panoramic and related 2D programs | Most general practices | Lowest cost of the digital options; no 3D |
| 2D pan with ceph arm | Adds lateral and PA cephalometric images | Orthodontic and pediatric offices, general offices doing ortho | Wider footprint, higher cost, larger shielding scope |
| Pan/CBCT combination | Pan plus 3D volumes | Implant, surgical, endo-heavy practices | Much higher cost and compliance burden; see our CBCT guide |
| Film pan | Film cassette in the rotating arm | Rarely a good purchase now | Processing chemistry, film supply, and conversion costs |
| Upgradeable 2D unit | 2D now, with a factory upgrade path to 3D or ceph | Offices expecting to add 3D within a few years | Confirm the upgrade is still offered and what it costs |
A decision guide
- General practice, mostly restorative and hygiene: a 2D digital pan covers the need. Put the money into good positioning training.
- Placing implants or doing complex extractions: consider a combination unit or plan referral for CBCT. Buying 2D now and 3D later can cost more than a combo unit once.
- Orthodontics: a ceph arm is standard. Decide between one-shot and scanning ceph (below).
- Space-limited office: measure the footprint, the rotation envelope, and wheelchair access before choosing a model. A ceph arm needs extra width.
Ceph arms: one-shot vs. scanning
Cephalometric arms come in two styles. Scanning ceph sweeps a narrow sensor across the skull over several seconds; it is common on dental combination units and less expensive, but patient movement during the sweep can distort the image. One-shot ceph captures the whole image at once with a large detector, which reduces motion artifacts but costs more. Either way, confirm the ceph software and licensing are included, the ear rods and nasion positioner are present, and the room layout allows the arm's width.
How to use it: daily operation and positioning
These steps are generic. Follow your unit's instructions for use (IFU), your state rules, and your office's written radiation safety procedures.
Start of day
- Power on the unit and workstation, and let the unit complete its self-test and warm-up if the IFU calls for one.
- Run the rotation test or ready check without a patient to confirm the arm moves freely and no error codes appear.
- Confirm the positioning lights work and are aligned with the bite block.
- Stock bite block covers and disinfectant, and check that chin rests and temple supports are clean and secure.
Positioning each patient
- Have the patient remove eyeglasses, earrings, necklaces, hair clips, facial piercings, removable appliances, and hearing aids if appropriate. Metal outside the trough creates ghost images on the opposite side of the image.
- Do not place a thyroid collar. It blocks the beam and forces retakes. A lead apron, if your state still requires one, must sit low on the shoulders and clear of the beam.
- Select the program and patient size, and raise the column so the patient can stand or sit tall.
- Ask the patient to step forward so the spine is straight, shoulders relaxed and down. A slumped neck puts the spine in the beam.
- Place a covered bite block and have the patient bite edge to edge with the incisors in the groove.
- Align the midsagittal plane with the vertical light so the head is neither rotated nor tilted.
- Align the Frankfort plane (the line from the lower orbit to the ear canal) horizontal, or as your unit's light specifies.
- Set the canine or trough light on the maxillary canine if your unit uses one.
- Close the temple supports gently, and ask the patient to close their lips, swallow, and press the tongue flat against the roof of the mouth.
- Tell the patient to stay still for the full rotation, step to your protected position, and expose.
- Review the image immediately against the error table below before releasing the patient.
Between patients and end of day
- Discard bite block covers, then clean and disinfect the bite block, chin rest, temple supports, and handles with an approved disinfectant. Do not spray into the unit.
- Return the unit to its home position.
- At the end of the day, shut down per the IFU, back up images per your plan, and log any errors or retakes.
Common positioning errors and what each looks like
Learn these patterns and you can correct most bad pans on the next exposure. Descriptions are general; exact appearance varies with the unit and trough shape.
| Error | What you see on the image | How to fix it |
|---|---|---|
| Chin tipped down | Exaggerated "smile" curve to the occlusal plane; lower incisors blurred and short; condyles may be cut off at the top; hyoid may overlap the mandible | Level the Frankfort plane; raise the chin slightly |
| Chin tipped up | Flat or reversed "frown" occlusal plane; hard palate shadow across the roots of the upper teeth; upper incisors blurred and magnified | Level the Frankfort plane; lower the chin slightly |
| Patient too far forward | Front teeth narrow and blurred; premolars overlap; spine may appear over the rami | Seat incisors in the bite block groove; check the canine light |
| Patient too far back | Front teeth wide and blurred; more ghosting; the image may look stretched in the anterior region | Bring the patient forward into the bite block groove |
| Head rotated (turned) | Teeth and ramus wider on one side and narrower on the other; midline off center | Align the midsagittal light; close temple supports evenly |
| Head tilted (canted) | Occlusal plane slants; one condyle and inferior border higher than the other | Align the midsagittal plane vertically; check that shoulders are level |
| Tongue not against the palate | Dark air-space band over the roots of the upper teeth | Have the patient swallow and press the tongue to the roof of the mouth during exposure |
| Slumped posture | Light, blurred triangular shadow of the cervical spine in the front midline | Step the patient forward and straighten the neck |
| Patient movement | Wavy or stepped outline of the inferior border or teeth, often in one region | Explain the scan length; stabilize with temple supports; consider a shorter program |
| Metal left in place | Bright object plus a larger, blurred ghost on the opposite side, higher up | Remove jewelry, glasses, appliances, and hair clips before positioning |
| Thyroid collar or apron in the beam | Bright band blocking the lower center of the image | Do not use a thyroid collar; keep any required apron below the beam |
Keep a laminated copy of your own office's best and worst pans next to the unit, labeled with the error. Staff learn positioning faster from their own images than from textbook examples, and a short monthly retake review keeps the habit alive.
Maintenance schedule
| Task | Frequency | Who | Notes |
|---|---|---|---|
| Replace bite block cover; disinfect contact points | Every patient | Clinical staff | Bite block, chin rest, temple supports, handles |
| Rotation check and error code review | Daily | Clinical staff | Note any unusual noise or hesitation |
| Check positioning lights and accessories | Daily | Clinical staff | Report misaligned lights; replace missing bite blocks |
| Image backup verification | Weekly or per your plan | Office manager or IT | Test a restore periodically |
| Retake and positioning review | Monthly | Dentist and lead assistant | Group retakes by error type |
| QA test with the manufacturer's phantom or test tool | Per manufacturer and state QA program | Trained staff or service provider | Keep results with your x-ray records |
| Software and firmware updates | As released, after compatibility check | IT with the dealer | Confirm compatibility with your practice software bridge |
| Preventive maintenance and calibration | Per manufacturer, often annually | Factory-trained technician | Mechanical, alignment, and sensor calibration checks |
| Performance evaluation | At installation and at state-set intervals | Registered service provider or qualified expert | Intervals vary by state |
Troubleshooting
Staff can fix positioning, patient preparation, software selection, and simple restarts. Rotation mechanics, alignment, calibration, the tubehead, the sensor, and any electrical work belong to a factory-trained technician.
| Symptom | Likely causes | What to try | When to call a technician |
|---|---|---|---|
| Positioning errors on many images | Technique, rushed setup, misaligned lights | Use the error table; retrain; check lights against the bite block | If lights are visibly out of alignment |
| Distortion even with careful positioning | Trough or rotation alignment drift, often after a move or impact | Take a phantom image and compare with baseline | Yes; alignment is technician work |
| Vertical bands or streaks on every image | Sensor calibration issue or detector fault | Restart unit and software; retake phantom | If bands persist |
| Scan stops mid-rotation | Arm contacted the patient's shoulder, exposure button released, collision sensor | Lower shoulders; check the patient's clothing and chair; hold the button for the full scan | If it stops without contact or with an error code |
| Unit will not reach ready state | Warm-up or cooling period, workstation not connected, door or interlock | Wait for cool-down; restart the acquisition software | If ready state never returns |
| Image does not arrive at the workstation | Network, acquisition software, or bridge issue | Check the network cable and acquisition software; do not re-expose until the image is located | Call imaging software support if needed |
| Grinding noise, jerky rotation, or column movement problems | Mechanical wear, drive issue | Stop using it and tag it out | Always |
| Images too light or dark overall | Wrong patient size or program | Select correct size and program; retake only if clinically needed | If correct settings still misexpose |
Film to digital conversions
If you own a film pan that still works mechanically, there are two main conversion routes:
- Retrofit sensor kits: a digital sensor module replaces the film cassette carriage, and a workstation runs the acquisition software. Several companies have sold these; Suni Medical Imaging's RetroPan kit is one example. A qualified technician installs the kit and adjusts the unit.
- Extraoral phosphor plates: the plate goes in a cassette in place of film and is read by a PSP scanner that accepts panoramic plate sizes. You keep the existing unit mechanics and gain a scanner that may also read intraoral plates. See phosphor plate scanners.
Before converting, price the kit, installation, software licensing, workstation, and any required testing, then compare with a used digital unit of similar age. An old film pan still has old mechanics and a tube with unknown wear, and conversion does not change that. Some resellers will not accept returns on units a buyer has converted, which is one more reason to decide before buying.
Safety and compliance
- FDA: panoramic units are extraoral source x-ray systems (21 CFR 872.1800, Class II) and must meet the federal performance standard in 21 CFR Part 1020. The installer files a report of assembly (Form FDA 2579).
- State radiation control program: registration, shielding plans (some states require them for pan and ceph rooms), acceptance testing, periodic evaluations, and operator rules vary. See our registration and inspection guide.
- ADA guidance: the 2024 ADA radiation safety report and the 2026 ADA and AAOMR patient selection recommendations are linked from the ADA x-rays topic page. Among other things, they call for imaging based on clinical need and the removal of artifacts before exposure.
- Infection control: treat bite blocks and contact points per the IFU and CDC guidance: disposable covers, then cleaning and disinfection.
- Interpretation: the whole image should be reviewed, not just the area of interest. The 2026 recommendations make the same point for both radiographs and CBCT.
General information only; confirm requirements with your state radiation control program and dental board.
Buying new vs. used
Panoramic units are durable and hold value, and many offices buy them used. The real cost includes deinstallation, freight, installation, calibration, software licensing, shielding, and testing. Our panoramic buying guide walks through that math.
Used panoramic unit checklist
- Model and serial number confirmed with the manufacturer as supported for parts and software
- Written answer on software license transfer to you at your address
- Recent sample images from this unit, including a phantom image if available
- Service and calibration history, including after any prior move
- Sensor included and working (it is often the most valuable part of a digital pan)
- Bite blocks, chin rests, temple supports, and ceph accessories (if any) present
- Deinstalled by a trained technician with transport locks in place
- Room fits the footprint, rotation envelope, ceph width, and electrical requirements
- Installer registered in your state and willing to file required reports and testing
- Shielding plan requirements confirmed for your room
Red flags: a digital pan sold without its sensor or with a sensor "sold separately"; no sample images; a unit taken down by movers or general contractors; an unsupported acquisition software version; a ceph arm listed without its software license; film units priced like digital units.
Rough price ranges and lifespan
As rough guidance that varies widely by model, age, features, condition, region, and year: a new 2D digital pan generally costs in the tens of thousands of dollars, a ceph arm adds meaningfully, and combination 3D units cost more still. Used units sell well below new, but installation, calibration, and compliance costs are similar either way. Mechanically, pans often last well over a decade; the practical limit is usually software and sensor support. See equipment lifespan by category.
Brands and models you will see
Examples include Planmeca ProMax 2D models, Carestream Dental CS 8100 (including ceph versions), Dentsply Sirona Orthophos models, Vatech PaX-i, and the DEXIS OP 2D. Older units such as the Sirona Orthophos XG and earlier Planmeca and Instrumentarium models are common on the used market.
Related guides
For 3D imaging, read CBCT units and buying a used CBCT. For the intraoral side, see intraoral x-ray units. For room planning, see operatory buildout and design. When you are ready to shop, browse the marketplace.
Always follow the manufacturer's instructions for use (IFU) for your specific model. Repairs involving electrical, pressure vessel, radiation, or gas line work belong with a qualified technician. Infection control and radiation rules vary by state. Prices are rough ranges that vary by model, condition, region, and year. ChairsideSource is not affiliated with any manufacturer named here.