The Role of Intraoral Scanners in Modern Prosthodontics

An intraoral scanner creates a digital surface record that can support restorative planning, laboratory communication and CAD/CAM production. It can make impression-taking more comfortable and efficient in suitable cases, but the scanner alone does not ensure an accurate bite, a complete preparation margin or a restoration that needs no adjustment. The useful question is whether the chosen system and recording method suit the restoration being planned.

This guide connects the optical technology to the clinical decisions: what is measured, which product features are model-specific, and how to interpret evidence about accuracy, comfort and workflow.

From optical capture to a usable record

Intraoral scanning records visible oral surfaces through successive optical views. Software combines overlapping frames into a surface model. This registration, often called stitching, is a potential source of accumulated error; a visually smooth model is not proof of geometric accuracy. The distinction matters particularly when recording an entire arch. Nagy and colleagues examined this directly by comparing corresponding points relative to the scan origin.

Different optical methods estimate depth in different ways. Projected-pattern triangulation uses a known relationship between the projected pattern, surface and camera view. Confocal methods use depth-dependent focus information. Neither name, by itself, establishes which scanner will give the best result for a particular indication. Hardware generation, software, scan strategy and the measurement method must also be identified.

Dedicated implant photogrammetry should be distinguished from routine intraoral surface scanning. For example, PIC workflows capture implant positions using specially identified transfers and combine those records with separately acquired soft-tissue scans. An intraoral scanner’s use of multiple images does not make it interchangeable with that implant-coordinate workflow. See the manufacturer’s implant-position capture instructions and soft-tissue integration guidance.

Understanding the named scanner systems

The following descriptions identify functions and documented generations, rather than rank products or imply that every model in a brand has the same capabilities.

• Planmeca Emerald: the original Emerald is described in the primary seven-scanner study as a three-colour laser, projected-pattern triangulation system. Planmeca’s contemporary publication identifies its three-laser colour acquisition. Active wavefront sampling is not the method reported for this device. The later Emerald S specifications explicitly list red, green and blue lasers, projected-pattern triangulation, and STL/PLY output. Keep the original Emerald and Emerald S generations separate when discussing specifications. Study methods; original Emerald publication; Emerald S specifications.
• Medit i700: a primary implant-model experiment identifies active triangulation for this scanner. It should not be described here as a dedicated implant-photogrammetry system. Medit’s i700 documentation describes a colour intraoral scanner; the implant-model experiment supplies the specific optical-method classification. Laboratory trueness results do not establish a guarantee of clinical full-arch fit.
• iTero: Element 1 and Element 2 used red-laser parallel confocal imaging in the cited comparison. The Element 5D additionally combines 3D capture, intraoral colour images and near-infrared imaging (NIRI). NIRI is an aid for detecting and monitoring interproximal caries above the gingiva; it is not the surface-scanning principle and should not be attributed to every Element model. The manufacturer describes it as complementing radiographs when appropriate. Optical-method comparison; Element 5D functions; NIRI scope.
• 3Shape TRIOS: the cited comparison identifies TRIOS 3 as a structured-light confocal system. Current TRIOS 3 documentation describes colour scanning, software-assisted removal of soft-tissue/artifact data and laboratory connections. These are capture and workflow capabilities, not proof that an automatically processed scan is complete. Features from newer TRIOS generations should be checked against their own documentation rather than assigned to the whole range.

Colour display, diagnostic support, shade communication and restoration design are different functions. A colour mesh does not independently validate the final restoration’s shade. Similarly, a scanner’s connection to a design platform does not mean the scanner itself performs every design or manufacturing step.

What comparative studies actually measure

Trueness concerns agreement with an accepted reference; precision concerns repeatability. Neither is identical to marginal fit, occlusal adjustment, patient comfort or restoration survival. Read a comparison by identifying its specimen or patient group, scanner and software, reference method, scan span and measured endpoint.

Mennito and colleagues’ 2019 cadaver-maxilla study found that, apart from Planscan, the investigated digital methods did not differ significantly from the conventional impression workflow for tooth-structure accuracy. Nagy and colleagues’ 2020 reanalysis of the same underlying data aligned models at the scan origin and found increasing deviation with distance for intraoral scans, with differences between methods. This illustrates how alignment and endpoint choice affect the apparent comparison. Neither experiment tested long-term restoration survival, and neither provides a current ranking of all scanner generations.

Clinical evidence also supports a more useful statement than “digital is always faster and painless.” In Gjelvold and colleagues’ randomized trial, 42 patients requiring tooth-supported single crowns or fixed partial prostheses up to six units were allocated to digital or conventional impressions. Mean total procedure time was 14 minutes 33 seconds for digital and 20 minutes 42 seconds for conventional impressions, and reported discomfort was lower in the digital group. These are findings from that trial’s workflow and patients, not promised times or an assurance of zero discomfort for another patient.

For single implant crowns, Joda and Brägger’s randomized crossover trial involved 20 patients who experienced both impression methods. Patients preferred the digital procedure, which also took less time in that setting. This supports discussing convenience for comparable single-tooth workflows; it does not validate every complete-arch implant or removable-denture protocol.

The 2025 auxiliary-device experiment tested four-implant maxillary models with parallel or angled posterior implants and three intraoral scanners. Scanner, implant arrangement and additional geometric references affected the findings. Its in-vitro design is important: an apparent advantage on a model is not proof of clinical passive fit or a reason to improvise an unvalidated scan-body accessory.

Checks that matter in prosthodontic workflows

For a prepared tooth, first establish that the preparation margin and relevant surfaces are actually visible in the record. The original Emerald manual separates model evaluation, erasing extraneous data, checking interproximal capture and creating or reviewing the margin. Its margin tool provides a way to inspect and revise a drawn line; drawing that line does not recover anatomy that was never recorded. Use the compatible device instructions and clinical tissue-management approach before rescanning a deficient area.

Review the opposing arch and recorded bite separately from the preparation scan. A detailed preparation surface can coexist with an incorrect interarch relationship. The same manufacturer’s manual includes bite alignment and evaluation as separate stages. Do not interpret a software contact display as a direct measurement of bite force.

For implant work, confirm that the recorded scan-body geometry and the selected component/library belong to the intended system. Keep a single-implant workflow distinct from a complete-arch one: the longer-span and implant-arrangement limitations in the cited model experiment are reasons to verify the applicable protocol and resulting prosthesis, rather than assume a complete-looking mesh establishes passive fit.

Data compatibility also needs a practical check. The original Emerald brochure lists open STL output; Emerald S documentation lists STL and PLY. The Element 5D documentation describes restorative STL export. Confirm what the receiving laboratory needs for the actual software version and treatment. A surface file is distinct from radiographic volume data: the Planmeca clinical workflow publication describes CBCT DCM data and intraoral STL records as separate inputs that can be combined in planning. An intraoral scanner does not acquire a CBCT volume. Original output format; Emerald S; Element 5D; combined workflow.

Two teaching decisions

Illustrative decision, not a reported patient case: a crown preparation looks complete on the colour model, but part of its margin cannot be followed in the surface view. The next step is to investigate visibility and capture quality and obtain an adequate record, rather than allow a suggested margin line to stand in for missing anatomy. The scan is an input to treatment, not evidence that the crown will fit without adjustment.

Illustrative decision, not a reported patient case: a team moves from routine single implant crowns to a complete-arch implant restoration. Before using the same scanning recipe, it must establish a suitable acquisition and verification workflow for that indication, including compatible components and any separate implant-position records. Comfort during scanning and geometric adequacy are separate questions. No patient outcome is inferred from these teaching examples.

Choosing and reviewing a workflow

A useful scanner assessment starts with the work the practice actually performs: the expected restorations, laboratory connection, staff training, infection-control requirements, computer configuration and access to support. Request model- and version-specific information, and assess the complete workflow rather than a headline scan time. Local cost, licensing and availability require current confirmation; this guide does not offer a price comparison.

Software assistance can help acquisition and communication, but it does not remove the need to examine the records. Keep a conventional or hybrid route available when it is clinically appropriate, and assess the delivered restoration independently. The strongest role for intraoral scanning is as one checked component of a prosthodontic workflow, with benefits and limitations matched to the patient, indication and evidence.

References and product documentation