3D ear scanning vs. ear impressions: which is better for audiologists?

Why the capture method matters

The National Institute on Deafness and Other Communication Disorders estimates that 28.8 million U.S. adults could benefit from hearing aids, and only about one in four adults 20 and over who could benefit has ever used them. While not every fitting requires a custom earpiece, every custom earpiece starts with an ear impression or digital scan.

What is 3D ear scanning?

3D ear scanning uses an optical scanner to map the geometry of the outer ear and ear canal, producing a digital impression that can be sent electronically to hearing aid manufacturers.

Two approaches exist in the market today:

• Laser and light-based scanning. The scanner sweeps the ear canal and concha with a light source, building a high-resolution 3D model from the reflected surface data. The Natus Sensory Otoscan uses noninvasive laser technology and converts more than one million data points into 3D digital files.
• Membrane-based scanning. A single-use membrane inflates inside the canal and conforms to the anatomy, creating a clean optical environment for the camera. Lantos Technologies developed this approach as an alternative capture method.

Either way, the scanning process ends with a digital scan rather than a physical object.

How traditional ear impressions work

The traditional impression process has changed very little in fifty years:

1. Perform otoscopy to check the canal for wax and debris.
2. Place an otoblock at the appropriate depth.
3. Inject silicone impression material into the canal and concha.
4. Wait for the material to cure, then remove and inspect the impression.
5. Package and ship the silicone impression to the earmold lab or manufacturer.

The method is familiar, inexpensive to start, and works on nearly every ear. Its weaknesses show up in the details: material blow-by past the otoblock, voids, distortion during removal, shipping delays, and shrinkage over time.

Where the two methods differ

Both methods end with a custom earpiece. The key differences lie in how the data is captured, transferred, and managed afterward.

Capture and output

• A 3D ear scan is optical. Nothing is injected into the ear canal, and the output is a digital file.
• A traditional impression is physical. Silicone impression material fills the canal and concha, cures, and gets removed as a solid object.

Getting the data to the manufacturer

• For Standard Otoscan and Otoscan Enterprise, scan files are uploaded to Otocloud, the dedicated cloud portal, where supported hearing aid manufacturers can access and download them the same day.
• Otoscan Standalone does not require Otocloud and allows scan data to be stored and managed locally.
• Silicone impressions have to be packaged and shipped, adding days before production begins.

What happens on reorders

• Scan data stays on file, so replacements and remakes can pull from the existing digital scan.
• Physical-impression workflows may require a new impression for future orders unless the manufacturer or lab has retained suitable digital or physical records.

Risk of distortion

• A digital file does not change after capture.
• Physical impressions can be affected by handling, removal distortion, voids, or dimensional changes, depending on material and technique.

Accuracy and fit

Accuracy is the argument audiologists care about most, and it comes down to remakes. Every remake means a second appointment, a longer wait for the patient, and clinic time that cannot be billed.

Natus Sensory reports that Otoscan reduces remake rates by 33 to 50 percent compared with the market average for custom products. A digital scan is not subject to the physical deformation or shrinkage that can affect impression materials after capture.

Patient comfort and safety

Traditional impressions can be uncomfortable for some patients. The impression material can feel cold and create a blocked sensation in the ear canal, while removal may be uncomfortable, particularly for patients with sensitive ears.

There is a clinical safety dimension as well. A case series published in the Annals of Otology, Rhinology & Laryngology documented six patients in whom impression material entered the middle ear during earmold fitting. The authors noted that these cases require ENT referral, that blind in-office removal carries real risk when the tympanic membrane cannot be fully examined, and that no standardized management approach exists once material has passed the otoblock. Related case reports have described silicone discovered in the middle ear years after the original fitting.

Digital ear scanning eliminates several challenges associated with traditional impressions, including the risk of material extending past the otoblock and the need for impression curing time. Patients can see their own ear scan in real time on screen. Showing a patient the 3D model of their own ear canal gives the audiologist a visual aid during hearing aid selection, and it pairs naturally with the counseling conversation that already happens during hearing aid fitting.

Turnaround time and digital workflow

A silicone impression has to be boxed, labeled, and shipped. Electronic transmission can allow the manufacturer or lab to begin processing sooner than with shipped physical impressions.

Stored scan data also pays off later. The same stored scan may be submitted to different participating manufacturers for compatible custom products.

Custom hearing protection

Custom earpieces are not limited to amplification. Regardless of protector type, NIOSH recommends individual fit testing to confirm adequate attenuation. Stored ear scans can simplify replacement orders when the existing scan remains clinically appropriate and is accepted by the manufacturer.

What the research says

A pilot study published in Bioengineering compared the two techniques directly using the Natus Otoscan. Adult earmold users wore earmolds made from each method, one set per week in randomized order.

• Participants significantly preferred 3D scanning and rated it more comfortable, partly because their ears were not plugged with silicone and partly because they enjoyed seeing their ear canal on screen
• Both techniques were perceived as safe
• There was no significant difference in how participants judged the resulting earmolds
• 3D scanning carried higher fixed costs but less variable cost and less variable procedure time
• Professional responses were shaped by clinician experience with each technique

The authors concluded that 3D ear scanning is a viable consideration for audiology practices.

When a traditional impression still makes sense

An experienced audiologist keeps both options available. Traditional ear impressions remain the better choice when:

• If occluding cerumen prevents adequate visualization or capture of the canal, it should generally be managed before proceeding with either technique.
• Complex or post-surgical anatomy may require individualized assessment to determine whether digital scanning or a conventional impression is appropriate.
• Patient cooperation and ability to remain still should be considered for both scanning and traditional impression techniques.
• A specific manufacturer or lab does not yet accept digital files.
• The clinic sees too few custom orders to justify the equipment cost.

Cost, training, and staffing

An ear scanner is a capital purchase, so the math depends on volume. Higher-volume clinics may offset the capital cost through reductions in remakes, shipping, and workflow time, depending on local economics and usage.

Scanning is a clinical skill that improves with repetition, and structured training shortens the ramp. Training multiple qualified staff members in scanning can increase scheduling flexibility, subject to local scope-of-practice requirements.