Intraoral scanner creating digital model of teeth

Are Digital Scans as Accurate as Traditional Dental Impressions? Find Out!

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Samir D’Costa in Health & Wellness October 2026 • 4 min read.

"A new study compares the accuracy of digital models created by intraoral scanners to manual measurements, revealing surprising insights for dental professionals."


In today's rapidly evolving dental landscape, digital technology is transforming how we approach patient care. From retainers and expanders to clear aligners, many appliances are now crafted directly from digital dental models, streamlining the process and potentially reducing both time and costs. By integrating digital models into clinical practice, dentists can minimize the need for traditional impressions and laboratory work, leading to more efficient workflows.

One of the most promising advancements is the use of intraoral scanners, which create highly accurate digital models. These scanners offer the potential to replace traditional impression methods, improving accuracy and reducing patient discomfort. But are these digital models truly as reliable as those created from alginate impressions? While many practitioners have embraced digital cameras and radiography, the transition to intraoral scanners has been slower, prompting questions about their accuracy and practicality.

A recent study investigated the accuracy of digital dental models generated by two popular intraoral scanners, comparing them to manual measurements. The goal was to determine if these scanners could accurately capture three-dimensional surface measurements along a curved line, a critical factor in various orthodontic and restorative procedures.

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Digital Scans Gain Ground

Intraoral scanners are now widely accepted as the standard for impression taking across the dental industry, reflecting a significant shift toward digital workflows. A 2025 study analyzing the accuracy of digital models from full-arch impressions using iTero and Primescan scanners demonstrates that research into scanner performance continues to advance. The dental intraoral scanners market continues to expand, with development, manufacturing, and distribution of these devices growing to meet clinical demand.

Digital vs. Conventional Impression Methods

Intraoral scanners capture direct optical impressions by projecting light onto dental arches, including prepared teeth and implant scanbodies, creating detailed 3D models without physical materials. Digital impressions offer several advantages over traditional methods, including improved efficiency, accuracy, and patient experience. However, conventional impression techniques remain relevant in certain clinical scenarios, and the choice between approaches depends on specific treatment requirements and practice capabilities.

The Evolution of Intraoral Scanning Technology

Intraoral scanners have evolved from bulky machines in the 1980s to today's sleek, AI-powered devices, representing an extraordinary technological journey. The introduction of these scanners transformed dental workflows by enabling clinicians to capture highly accurate 3D digital impressions directly from patients' mouths. This evolution has made intraoral scanning an essential part of modern digital dentistry, supporting CAD/CAM restorations, implant planning, orthodontics, and clear aligner therapy.

The Study: Comparing Digital and Manual Measurements

Intraoral scanner creating digital model of teeth

The study, published in the American Journal of Orthodontics and Dentofacial Orthopedics, aimed to evaluate and compare digital dental models generated from two commercial intraoral scanners with traditional manual measurements. Researchers used dry mandibles (n = 61) with intact dentition, digitizing them with two chair-side intraoral scanners: the Cadent iTero (Align Technology, San Jose, Calif) and the Lythos Digital Impression system (Ormco, Orange, Calif).

Once digitized, the three-dimensional models were converted into stereolithography files and analyzed using specialized software to obtain curvilinear measurements. These measurements were then compared to manual measurements taken directly on the mandibular teeth using digital calipers. Various locations on the dental arch were measured in different directions to ensure a comprehensive comparison.

Here's a breakdown of the key methods used:
  • Digital Scans: Mandibles were scanned using Cadent iTero and Lythos Digital Impression systems.
  • Manual Measurements: Direct measurements were taken on the mandibles using digital calipers.
  • Curvilinear Measurements: Measurements were performed along curved lines on the dental arch.
  • Statistical Analysis: One-sample t-tests and linear regression analyses were used to compare the data. Bland-Altman plots were created to graphically assess accuracy.
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Expanding Clinical Applications

Recent systematic reviews and meta-analyses have compared the accuracy of intraoral scanners against intraoral cameras, radiographs, and histological methods for diagnosing dental caries. Intraoral scanners have expanded beyond model creation to become important diagnostic tools for detecting oral diseases, dental wear, and biofilm presence. Hardware innovations and software breakthroughs have improved scanning efficiency and accuracy, with scanners now serving as promising tools for comprehensive oral health diagnostics.

Limitations and Disadvantages

Despite their advantages, intraoral scanners have notable limitations compared to conventional impression techniques. Factors such as learning curve, equipment cost, and challenges with certain clinical situations—like scanning edentulous ridges or capturing subgingival margins—can limit their effectiveness. The technology's disadvantages must be weighed against benefits when clinicians decide whether to adopt digital impression workflows in their practices.

Comparing Digital and Traditional Approaches

The comparison between digital scans and traditional impressions involves multiple factors including accuracy, patient comfort, workflow efficiency, and cost-effectiveness. While digital scanners eliminate the discomfort of conventional impression materials, their performance can vary based on scanner type, operator experience, and clinical conditions. Clinicians must consider these variables when determining which approach best suits their practice needs and patient populations.

The study focused on curvilinear measurements to replicate real-world clinical scenarios, measuring along the long axis of teeth and crestal bone surfaces. Statistical analyses, including t-tests and Bland-Altman plots, were used to compare the accuracy of the digital and manual methods. The level of significance was set at P < 0.05.

The Verdict: Are Digital Scans Ready for Prime Time?

The study's findings suggest that intraoral scanners can produce digital dental models that are comparatively accurate when performing direct surface measurements along a curved line in three dimensions. While there were no significant differences between the paired methods, Bland-Altman analysis revealed random errors in all comparisons. The lowest mean bias was observed when comparing the two intraoral scanners directly, indicating a high level of agreement between them.

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Diagnostic Capabilities Beyond Impressions

Intraoral scanners have proven valuable not only for obtaining 3D digital dental models but also as promising tools for oral health diagnostics. Recent literature highlights their applications as detection systems for various oral cavity pathologies, extending their clinical utility beyond traditional impression-taking. This expanded diagnostic capability positions intraoral scanners as multifunctional instruments in modern dental practice.

Continued Innovation Ahead

The field of intraoral scanning continues to evolve with ongoing technological advancements and expanding clinical applications. Future developments are likely to focus on improving accuracy, expanding diagnostic capabilities, and integrating artificial intelligence for enhanced treatment planning. As the technology matures, intraoral scanners are expected to become even more integral to comprehensive dental care delivery.

Accuracy Challenges and Technology Selection

Despite growing adoption, challenges related to the accuracy of digital impressions remain, with factors influencing scanning precision and trueness still being identified and studied. The wide variety of intraoral scanner technologies and system generations poses a challenge for dentists seeking to invest in appropriate equipment. Ongoing research aims to better understand the factors that affect scanning accuracy to optimize clinical outcomes.

Patient Experience and Clinical Outcomes

Transitioning from traditional analog workflows to digital impressions significantly enhances the accuracy, speed, and comfort of the impression process for patients. Intraoral scanners capture detailed, high-resolution images in real-time, eliminating the need for conventional impression materials that often cause discomfort. However, factors like dental crowding can impact the trueness and precision of different scanner systems, highlighting the importance of considering patient-specific variables in clinical decision-making.

How scan differences compare with accuracy thresholds

  • 0.022; median 0.015 mmThe reported absolute mean difference between digital plaster casts and intraoral scans was 0.022 mm, with a median of 0.015 mm. These differences are below the cited 0.20 mm threshold for clinical acceptability and the suggested 0.30 mm accuracy level for orthodontic study models.[1] [2]

How other comparisons frame digital accuracy

A separate full-arch comparison reported different trueness ranges for full arches and for anterior and posterior segments, showing that the size of the difference can depend on which part of the arch is measured.[3]

Other evidence reports minor, clinically insignificant differences between direct and indirect measurements on plaster and digital models, while a review found contradictory results when digital scans were compared with conventional scans. Together, these sources indicate that conclusions depend on the comparison and measurement context.[4] [5]

Some comparisons found no statistically significant difference between scanners, yet deviations may still occur in posterior mandibular areas. This distinction matters because a lack of detected difference does not mean the measurements are identical throughout the arch.[2]

What remains uncertain about scan performance

  • How consistently do full-arch scans perform in living patients? The available evidence notes a shortage of in-vivo complete-arch comparisons, while some accuracy research has relied on laboratory conditions that cannot reproduce actual oral conditions.[6] [7]
  • How much do oral conditions and scanning technique alter results? Reflective surfaces, moving soft tissues, variations in sensor distance, and image-stitching challenges may affect capture, while accumulated alignment errors can be most pronounced where the arch changes curvature abruptly.[1] [8] [9]
  • How robust are findings across operators, equipment, calibration, and measurement environments? These factors contribute to variation, and the evidence base for full-arch accuracy and patient satisfaction has been described as limited.[10] [11]

Sources

  1. Accuracy of intraoral scans in the mixed dentition: a prospective non-randomized comparative clinical trial (pmc.ncbi.nlm.nih.gov)
  2. Comparison of two intraoral scanners based on three-dimensional surface analysis (progressinorthodontics.springeropen.com)
  3. Trueness of full-arch dental models obtained by digital and conventional impression techniques: an in vivo study. (pubmed.ncbi.nlm.nih.gov)
  4. Orthodontic measurements on digital study models compared with plaster models: a systematic review. (pubmed.ncbi.nlm.nih.gov)
  5. Clinical aspects of digital three-dimensional intraoral scanning in orthodontics – A systematic review (pmc.ncbi.nlm.nih.gov)
  6. Validation of Digital Impressions’ Accuracy Obtained Using Intraoral and Extraoral Scanners: A Systematic Review (pmc.ncbi.nlm.nih.gov)
  7. Dimensional Accuracy of Intraoral Scanners in Recording Digital Impressions of Post and Core Preparations: A Systematic Review (pmc.ncbi.nlm.nih.gov)
  8. Effect of scanning strategies on the accuracy of digital intraoral scanners: a meta-analysis of in vitro studies (pmc.ncbi.nlm.nih.gov)
  9. Comparative accuracy of complete-arch intraoral scans using full-scan and segmental-and-merge strategies (pmc.ncbi.nlm.nih.gov)
  10. Intraoral Scanner Technologies: A Review to Make a Successful Impression (pmc.ncbi.nlm.nih.gov)
  11. Computerized Casts for Orthodontic Purpose Using Powder-Free Intraoral Scanners: Accuracy, Execution Time, and Patient Feedback (pmc.ncbi.nlm.nih.gov)

About this Article -

Written with AI assistance from published research, and reviewed by the Mystum team. See our About page for more information.

Everything You Need To Know

1

What are the key advantages of using intraoral scanners in modern dental practices, and how do they improve patient care?

Intraoral scanners offer several key advantages in modern dental practices. They create highly accurate digital models, which streamline the process of creating dental appliances such as retainers, expanders, and clear aligners. This shift minimizes the need for traditional impressions and laboratory work, leading to more efficient workflows. By reducing patient discomfort associated with traditional impression methods and potentially reducing time and costs, intraoral scanners significantly improve the overall patient experience.

2

How did the study compare the accuracy of digital dental models from the Cadent iTero and Lythos Digital Impression system with traditional methods?

The study compared the accuracy of digital dental models from two intraoral scanners, the Cadent iTero and the Lythos Digital Impression system, with manual measurements using digital calipers. Researchers digitized dry mandibles with intact dentition using both scanners, converting the models into stereolithography files for curvilinear measurements. These measurements were then compared to direct manual measurements taken on the mandibular teeth. Statistical analyses, including t-tests and Bland-Altman plots, were used to assess the accuracy of each method.

3

What were the specific methods used to evaluate the accuracy of the digital dental models in the study, and what did the statistical analysis reveal?

The study employed several methods to evaluate the accuracy of digital dental models. Mandibles were scanned using the Cadent iTero and Lythos Digital Impression systems. Manual measurements were taken using digital calipers. Curvilinear measurements were performed along the dental arch. Statistical analyses, including one-sample t-tests and linear regression analyses, were used to compare the data. Bland-Altman plots were created to graphically assess accuracy. The statistical analysis revealed that there were no significant differences between the paired methods but that Bland-Altman analysis revealed random errors in all comparisons. The lowest mean bias was observed when comparing the two intraoral scanners directly, indicating a high level of agreement between them.

4

What are the practical implications of the study's findings for dental professionals considering the transition to intraoral scanners?

The study's findings suggest that intraoral scanners, such as Cadent iTero and Lythos Digital Impression systems, can produce digital dental models with comparable accuracy to traditional manual measurements. This implies that dental professionals can confidently integrate these scanners into their practices for various procedures. The use of intraoral scanners can lead to more efficient workflows, reduced patient discomfort, and the potential for time and cost savings. However, practitioners should be aware of the random errors identified in the study, even if not significant, so understanding the limitations of the technology is crucial.

5

Beyond accuracy, what other factors make intraoral scanners a beneficial addition to a dental practice, and how do they affect the patient experience?

Besides the accuracy of the digital models, intraoral scanners offer several other benefits. They streamline the process of creating dental appliances, such as retainers, expanders, and clear aligners, by removing the need for physical impressions. This reduces patient discomfort, a significant improvement over traditional impression methods. Digital models allow dentists to visualize the patient's mouth in detail, facilitating better communication and treatment planning. The efficiency of the process leads to reduced chair time and potentially lower costs, contributing to an enhanced patient experience. Digital workflows also offer the advantage of easily storing and sharing patient data, making it more convenient for both the dentist and the patient.

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