How to choose an ear impression scanner
The perfect fit begins with the right scan – but how do you choose the right scanner? This guide walks you through the world of ear impression scanners and what to consider before investing.
In audiology and custom-fit hearing product manufacturing, the tools you choose to work with can significantly impact both the quality of your products and the efficiency of your workflow.
When manufacturing custom-fit products the lab will need a three-dimensional model of the patient’s ear canal. There are two ways to create this model: by using an in-ear scanning device or by making an impression, resulting in a detailed mould of the ear canal and outer ear. In the latter case, the clinic or lab will need an ear impression scanner to digitize the impression so that they can begin the digital design process.
In this article we will explore what ear impression scanners can do – and what to consider before choosing one.
What is an ear impression scanner?
An ear impression scanner is a specialized 3D scanner designed to digitize physical ear impressions. These impressions, traditionally made from silicone or other soft moulding materials, capture the intricate shapes and curves of a patient’s ear canal and outer ear.
By scanning the moulds and turning the physical impressions into digital files, manufacturers can model highly customized hearing aids, in-ear monitors, earpieces, earplugs, and earmoulds faster and with greater precision than through conventional, manual production methods.
How do ear impressions work?
The ear impression scanner creates a digital file for you within seconds (or minutes, depending on the model you choose). The scanning process involves placing the physical ear impression into the scanner, where multiple cameras and light sources capture the object’s shape from all angles.
The way the scanner works is by simultaneously projecting light onto the scanned object and capturing several images of the object with on-board cameras. Combined, this will generate a 3D model of the object right away.
Benefits of ear impression scanners:
- Digital workflow integration: Scanned impressions can be quickly sent to manufacturers or integrated directly into CAD design software.
- Accuracy: Advanced scanners capture the minute details from the impressions, ensuring a better fit and superior comfort for patients using the final product.
- Faster turnaround times: Digitization speeds up the overall production process, reducing lead times for custom hearing devices.
- Remote collaboration: Digital files make it easy to collaborate across locations without physically shipping impressions.
How ear impression scanners compare to in-ear scanning
In recent years, in-ear scanning – where the ear canal is scanned directly without first creating a physical impression – has emerged as an alternative to traditional impression-taking methods. At first glance, it sounds like the future: faster, more direct, and no need for impression material.
But there are still several important reasons why ear impression scanners remain the more accurate and reliable option.
Accuracy is a major concern with in-ear scanning. Capturing the entire depth and fine details of the ear canal is difficult when working directly in a patient's ear. Narrow passages, sharp bends, and the presence of cerumen and hair make it challenging for in-ear scanners to reach the full depth of the canal, and even small patient movements can cause incomplete scans.
In contrast, an ear impression provides a full, stable replica of the ear that can be scanned carefully and completely in a controlled environment, leading to consistently high-quality digital models.
Workflow flexibility is also a key advantage for impression scanning. Having a physical impression gives clinics and labs a tangible backup in case rescanning is needed later. It also allows for more manual adjustments if required. With in-ear scanning, if the original file is incomplete or corrupted, the entire patient scan might need to be repeated.
While in-ear scanners continue to improve, the technology often comes with higher costs and steeper learning curves. Ear impression scanners offer predictable, repeatable results and are typically more affordable.
What to consider when comparing ear impression scanners
While there are differences in the way different models of scanners function, scan technology has reached an evolutionary point where many scanners perform roughly the same way. Comparing the quality of ear impression scanners will not show big differences and will not necessarily tip the scale in favour of one model or other (in most cases).
However, it does pay off to consider surrounding factors such as software, surface detail scanning and support options.
Colour and texture scanning
Choosing a scanner with texture scanning features will capture every detail of the impression accurately and give the absolute best starting point for the further modelling process. When the scan reflects the impression in true-to-life colour, it allows for easy identification of challenging areas that require special attention or adjustments during the design process, since the manual annotation on the impression are transferred to the digitized scan.
Speed and number of cameras
Ear impression scanners with multiple cameras can capture finer details in a shorter time, by capturing the impressions from several angles. The number of cameras reflects the level of accuracy you can reach with the scanner and allows for the scanner to digitize two impressions in seconds. If you opt for a scanner with an open design, changing impressions becomes faster and easier – further improving scan efficiency.
Accuracy
Accuracy is one of the most important specs to look at when evaluating ear impression scanners. It’s also one that’s often misunderstood. So, let’s break it down.
Scanner accuracy is typically measured in microns, where one micron equals one thousandth of a millimetre. Most high-quality scanners for audiology applications operate below the 16-micron range. At that level, the scanner is capturing extremely fine surface details, which is enough to precisely represent the complex curves and contours of an ear impression for custom fitting.
That said, it’s important to put ultra-high accuracy into context. While it might be tempting to chase the scanner with the lowest micron rating, there’s a practical limit to how much value that brings. Most 3D printers used in hearing aid manufacturing don’t operate at the same ultra-fine resolutions as the scanners themselves. So, once you’ve reached a high-accuracy threshold you’re already well within the range needed for producing perfectly fitted custom products. Going beyond that may not translate into noticeable improvements on the final result.
In short: accuracy matters, but what you really want is reliable, repeatable precision that fits seamlessly into your full production workflow.
Scanning software
An ear impression scanner is not a standalone solution. It needs some form of scan management software to display the 3D file from. This is often included with the purchase of the scanner. Another important factor to consider is how well the scanner integrates with production management software and CAD solutions that enable the modellers to work on the file.
Support options
Like any professional equipment, scanners will at some point need updates and support. What kind of support setup is offered is an important factor to consider, when choosing an ear impression scanner. It may come with an extra cost or – like in the setup provided by 3Shape Audio – may be included with the purchase of the scanner.
The price of the scanner
No doubt: price is an important comparison point for ear impression scanners. However, it is important to consider the total cost of ownership when choosing a scanner. A cheaper scanner that lacks critical features, reliable support or do not include upgrades, can end up costing more in the long run.
If you regularly ship patients’ impressions to your manufacturer, the costs of postage and time spent on logistics can quickly add up, often exceeding 100 Euros per week. In that light, it becomes clear how quickly an ear impression scanner can pay for itself.
Which scanner is right for you?
