The intraoral scanner (IOS) represents a significant advancement in modern dental practice, replacing the traditional impression process, which often involved bulky trays and putty-like substances. This handheld optical device digitally captures the geometry of the teeth, gums, and palate, transforming the clinical workflow. This shift to digital impression-taking is central to the concept of digital dentistry, enabling streamlined processes and improved communication between the clinic and the dental laboratory.
Defining the Technology
An intraoral scanner is a compact, wand-shaped device that captures the three-dimensional architecture of the oral cavity. It acquires a series of high-speed images instantly processed to form a digital impression and generate highly accurate 3D models of the patient’s dentition. These models are often represented as a Standard Tessellation Language (STL) file, a standard format used for computer-aided design and manufacturing (CAD/CAM) workflows in dentistry.
Some advanced scanners also produce Polygon File Format (PLY) or Object File Format (OBJ) files, which include color and texture information in addition to geometry. These digital models, sometimes called a “digital cast,” eliminate the need for physical stone models. The detailed, open-source file format allows the digital impression to be universally shared and used by various dental software and manufacturing equipment.
How the Scanning Process Works
The process relies on projecting a structured light pattern or a laser onto the surface of the teeth and soft tissues. A sophisticated optical sensor captures the pattern as it is reflected and distorted by the oral structures. By analyzing this distortion, the scanner calculates the exact distance and geometry of every point on the surface.
This light-based process captures thousands of individual images per second. Specialized software immediately stitches these sequential images together in real-time, creating a continuous, three-dimensional digital model. The software’s algorithms align the data points into a cohesive digital mesh, providing the clinician with immediate visual feedback to ensure complete coverage and accuracy. Structured light scanning, which uses white or blue light, is commonly favored for its accuracy, although laser scanning may offer a faster acquisition speed.
Key Clinical Applications
The high-resolution digital models serve as the foundation for a wide range of restorative and orthodontic treatments. In restorative dentistry, the precision of the digital impression is utilized for the design and fabrication of fixed prosthetics, including crowns, bridges, inlays, and onlays. The digital file is sent directly to a laboratory, where the restoration is milled or 3D-printed for a precise fit.
The scanner plays a role in orthodontics by providing 3D data for planning clear aligner therapy and producing retainers. The digital impression is also combined with cone-beam computed tomography (CBCT) data to create accurate surgical guides for dental implant placement. This process, known as guided surgery, allows for virtual planning of the implant position, which is then translated to the patient’s mouth via a 3D-printed guide fabricated from the scan data.
The technology is also a diagnostic tool, allowing clinicians to establish a baseline model for long-term monitoring. By superimposing scans taken at different appointments, the software can precisely track minute changes in tooth position, tooth wear, and gingival tissue recession over time. This objective measurement is far more sensitive than traditional visual assessment techniques.
Patient Experience and Comfort
The patient experience is significantly improved compared to the conventional impression method. Since the process involves moving a small wand over the teeth, it is non-invasive and does not require messy, bad-tasting impression materials. This eliminates the discomfort and anxiety often associated with traditional impressions, particularly for patients who have a sensitive gag reflex.
The entire scanning procedure is quick, with a full-arch scan often taking only a few minutes. This reduced chair time and the ability to see the digital model of their teeth immediately enhance patient engagement and communication regarding treatment needs. Patients overwhelmingly prefer the digital scanning experience due to its speed, comfort, and cleanliness.