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How intraoral scanners work: technology, process, and clinical implications
An intraoral scanner is a digital imaging device used to capture 3D data of teeth and oral structures. It works by projecting light onto the surfaces of the teeth and recording the reflected data. This data is processed into a digital 3D model used for diagnosis, treatment planning, and digital dental impression workflows in dentistry.
Understanding how intraoral scanners work is important for interpreting scan quality, accuracy, and clinical outcomes. The scanning process involves capturing optical data, processing it in real time, and converting it into a usable digital model. Each stage influences how accurately the final model represents the patient’s dentition.
A clear understanding of this process helps explain both the capabilities and limitations of intraoral scanning technology, including its role within digital dentistry workflows.
What is an intraoral scanner and what does it actually do?
In clinical use, an intraoral scanner captures a digital impression by scanning the surfaces of the teeth directly inside the patient’s mouth and is increasingly considered essential equipment in modern dental practice.
Modern systems are designed to be ergonomically suited for intraoral use, including devices with a compact intraoral scanner design.
The device is moved across the dentition, collecting visual data that is continuously processed into a 3D representation.
As the scan progresses, the system builds the model in real time, allowing the clinician to see the captured areas and identify any missing data.
The output of intraoral scanning is a digital dental impression that can be stored, analyzed, and shared between clinics and laboratories as part of a digital dentistry workflow.
An intraoral scanner converts optical data from the surfaces of the teeth into a 3D digital model through a continuous scanning workflow. This process combines image capture, real-time data processing, and model generation into a single workflow.
During scanning, the device records optical data from multiple angles and positions. The software processes this data as it is captured, gradually building a complete digital representation of the dentition.
The final output is a digital dental impression that can be used for treatment planning, CAD/CAM design, and laboratory fabrication.
Process summary
An intraoral scanner projects light onto the teeth, captures the reflected data, processes it into a 3D surface model, and generates a digital dental impression for clinical use and laboratory workflows.
Step 1: Optical capture of tooth surfaces
The scanning process begins with optical capture. The intraoral scanner projects light onto the teeth and surrounding tissues, and imaging sensors record the reflected data.
Thousands of images are captured in rapid succession. These images represent different angles and positions of the tooth surfaces and form the basis for further processing.
Step 2: Real-time data processing
The captured images are processed by scanning software in real time. Ongoing software updates can improve processing performance, stability, and workflow efficiency. The system aligns and stitches the images together to create a continuous representation of the scanned area.
This process involves converting image data into point clouds and surface geometry, while continuously updating the model as additional scan data is captured. The software also filters out irrelevant data and ensures that only usable surface information is included.
Step 3: Creation of a digital dental impression
Once data has been captured and processed, the system generates a complete 3D digital model of the patient’s dentition.
This digital dental impression represents the geometry of the teeth and gingiva and can be used for diagnosis, treatment planning, and the design and manufacture of dental restorations within a digital workflow.
How does an intraoral scanner work?
Intraoral scanners use optical systems and software to capture and process 3D data from teeth and oral structures. These technologies influence how surface data is captured, processed, and converted into a usable digital model.
Structured light and laser-based systems
Many intraoral scanners use structured light or laser projection. A known light pattern is projected onto the teeth, and sensors record how the pattern deforms across the surface.
This deformation allows the system to calculate depth and surface geometry, forming the basis of a 3D representation. Structured light systems are commonly used due to their ability to capture detailed surface information at high speed and resolution.
Confocal imaging and triangulation
Confocal imaging and triangulation are techniques used to determine depth from optical data.
Confocal imaging captures multiple images at different focal depths to isolate sharp surface data, while triangulation calculates the position of a surface point by measuring angles between the light source, object, and sensor.
Together, these methods enable scanners to build accurate depth maps from a sequence of 2D images, which are then combined into a 3D model.
What affects intraoral scanner accuracy?
Several factors influence the accuracy of intraoral scanning, including both clinical conditions and how the scan is performed.
- Scanning technique and path used during image capture
- Accessibility of intraoral areas, especially interproximal and distal surfaces
- Presence of saliva, reflections, and soft tissue movement
- Optical properties of teeth, including translucency and surface texture
- Software algorithms used for image stitching and data processing
Managing these variables is important to ensure consistent and reliable scan results in clinical practice.
Digital scan accuracy vs traditional impressions
Digital and conventional impression methods differ in how accuracy is achieved and maintained throughout the workflow.
Traditional impressions rely on physical materials that can be affected by distortion, expansion, or handling during multiple manual steps. Each stage introduces potential variation in the final model.
Digital intraoral scanning captures data directly and reduces the number of steps required to produce a usable model. This minimizes the risk of material-related errors and allows for more consistent data handling.
Overall, both methods are clinically acceptable, but digital workflows can offer advantages in repeatability, data consistency, and integration with CAD/CAM systems.
Impact on restorative dentistry
In restorative dentistry, intraoral scanners provide accurate digital impressions that support the design and fabrication of restorations.
This affects restorative workflows in the following ways:
- Precise input for crowns, bridges, and implant restorations
- Accurate fit and potentially fewer adjustments during placement
- Better integration with CAD/CAM design and manufacturing systems
Intraoral scanner accuracy refers to how precisely a digital scan represents the true shape and position of teeth and oral structures and this plays a critical role in treatment outcomes. Accuracy is typically assessed in terms of trueness (how close the scan is to the actual geometry) and precision (how consistent repeated scans are).
Clinical evidence indicates that intraoral scanners can achieve accuracy comparable to, and in some cases exceeding, traditional impression methods, depending on the indication and scanning conditions.
Summary: How intraoral scanners convert light into digital dental models
- Check-out clinical studies
You will want to focus on intraoral scanner accuracy. “There are plenty of independent studies available. The 3Shape website has a library of clinical studies for your review.” - Test models
Test various scanner models at shows and see which brand feels most comfortable in your hand and has the easiest software to work with. Dr. Mark McOmie created a terrific model for evaluating intraoral scanner manufacturers. - Test in vivo
Most importantly, test the scanner on a mouth in vivo. “Scanning plastic or acrylic models is fine for checking the feel, but you really need to see how the scanner reacts to saliva, hard to reach areas, speed, and comfort.
Remember, every scanner in the market can scan a model. Not every scanner can completely scan a mouth.”
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