The dental industry is rapidly evolving, driven by technological innovations that are transforming patient care, diagnosis, and treatment planning. The transformation from film to digital radiographs has greatly enhanced the clinician’s ability to interpret caries and pathology while improving patient communication. Over the past 20 years, these 2D images have been augmented with 3D images made possible with cone beam computed tomography (CBCT) and interactive treatment planning software. Physical impressions for crown and bridge dentistry have now been modernized with intraoral scanning, creating the first digital workflows when combined with milling machines in the dental laboratory and then in the dental office. Dental implants can now be restored with information gained from specific scanning abutments designed to capture the intraoral position of the implant and surrounding tissue with an intraoral scanner and software that seamlessly transfers this data to the dental laboratory clinician.
While intraoral scanning has been widely adopted for single-tooth restorations, its application in capturing multiple implants—particularly in full-arch cases—presents unique challenges. Therefore, one area undergoing significant transformation is how to accurately capture multiple implants, especially full-arch implants, which is traditionally a complex process that demands a high level of precision. As intraoral scanning falls short in accuracy, photogrammetry was developed to provide this extra layer of exactness necessary to allow the dental laboratory technician to design superstructures that will fit passively on multiple implants without the need for a physical verification index. Innovative technology has been effective as a solution to intraoral scanning to achieve this level of precision, yet it still requires a soft-tissue scan to capture the soft tissue. Additionally, despite the positive aspects of photogrammetry, the devices are an expensive addition for a clinician to own when both devices are needed to capture all of the intraoral data that is needed for the restorative process. This is where intraoral photogrammetry, an emerging technology, comes into play, redefining accuracy and efficiency in full-arch implant procedures.
The Digital Transformation in Dentistry
For decades, clinicians relied on traditional impression techniques to create models of the oral cavity. These conventional methods involve using physical materials to capture the shapes and contours of teeth, soft tissue, tooth preparations, and more recently, dental implant positions. Traditional impressions also often require retakes, leading to patient discomfort, contamination with blood and saliva, increased chair time, and additional associated costs. Although these analog materials can be effective, they are prone to deformation, patient movement, and inaccuracies, making it difficult to achieve the precision required for complex implant cases. To overcome the issues of analog impression materials and related laboratory protocols, intraoral scanning was introduced, which offered clinicians a digital solution that simplifies the impression process. Using a handheld device, clinicians and dental assistants can quickly capture a 3D digital image of the patient’s oral cavity, which can then be used to create virtual models and prosthetics designed with advanced CAD/CAM software applications. However, intraoral scanning has its own set of challenges for natural tooth preparations, single and multiple implants, and particularly when it comes to capturing full-arch dental implants. When scanning large areas, such as a full arch with multiple implants, errors can accumulate due to the limitations related to the native topography of the oral cavity, the curve of the arch, necessary software “stitching” algorithms, image overlap, and inherent distortions. The goal of implant prosthetics is to provide an aesthetic and functional treatment outcome that is dependent on a passive fit of the prosthesis to the implants. The limitations of intraoral scanning can significantly impact the predictability of prosthetics, as minor discrepancies can lead to major alignment errors and fitting problems, which, if left undetected, can lead to potential complications and implant failure. Therefore, despite their usefulness in allowing for digital workflows for many procedures, traditional intraoral scanners often fall short in full-arch dental implant cases, making these scenarios especially complex and prone to inaccuracies.
Understanding the Limitations of Intraoral Scanning for Full-Arch Cases
Intraoral scanners work by using a series of images taken in rapid succession, which, through the magic of computer software algorithms, are then stitched together to form a virtual 3D model. While this technique is effective for single-tooth restorations, it is prone to errors when larger areas are scanned, especially when multiple implants are involved, such as for full-arch reconstruction. The main issue arises from the need to align each captured image (scanning abutment) correctly with the next. When the scanner moves from one segment of the arch to another, even small alignment errors can lead to a loss of accuracy, creating cumulative errors that impact the passivity and final fit of the prosthetic, which may not seat correctly, and result in poor fit and function. Moreover, intraoral scanners often struggle to maintain a consistent line of sight over the entire arch, especially in areas where there are obstructions such as cheeks, tongue, or pre-existing restorations. This can lead to incomplete data capture, further compounding the problem. Another issue with traditional intraoral scanning in full-arch cases is related to soft-tissue capture. Full-arch implant restorations often involve complex soft-tissue structures that need to be accurately represented in the digital model. Traditional intraoral scanners can struggle to capture the subtle details of these soft tissues, leading to inaccuracies in the intaglio surface of the final prosthetic design. These limitations make it difficult to achieve a precise and predictable fit, particularly when implants are placed at varying angles or depths.
The Rise of Photogrammetry in Dental Implantology
To address these drawbacks, the dental community turned to photogrammetry—a technique that uses multiple photographic images taken from different angles to calculate the precise 3D coordinates of fixed points. Photogrammetry has been widely used in industries such as metrology, engineering, and aerospace for its high precision, and it has recently made its way into dentistry. In dental applications, photogrammetry involves using specialized scan markers attached to dental implants, which serve as reference points for the photogrammetric device. The device then calculates the exact positions of these markers, allowing for the precise capture of implant positions.
To achieve the next level of accuracy with traditional implant procedures, extraoral photogrammetry (EPG) systems are often used. These devices, handheld and positioned outside the patient’s mouth, capture multiple images of the markers from various angles (Figure 1). The images are then processed and merged into a single 3D model using specialized software applications. While extraoral photogrammetry systems are known for their exceptional accuracy, they come with certain limitations. The extraoral nature of the system requires a stable platform and consistent lighting conditions, making it less adaptable for intraoral use. Additionally, EPG systems typically require separate scans for the implants (Figure 2) and the surrounding soft tissue (Figure 3). These separate data files are then exported and sent via the internet/cloud to the dental laboratory technician, who will manually merge the files utilizing a dental CAD software application. This process is time consuming and requires a high level of technical expertise, thus limiting its practicality for everyday clinical use. Despite these drawbacks, extraoral photogrammetry has been shown to achieve micron-level accuracy in capturing implant positions, making it a valuable tool for complex full-arch cases. Additionally, there are only a handful of manufacturers of these devices, which results in high purchase costs. Therefore, due to its complexity and cost and the need for a separate intraoral scanning (IOS) device to capture soft tissue, extraoral photogrammetry is not widely used outside of specialized centers and advanced prosthodontics practices. These restrictive issues have led to the development of a more streamlined approach: intraoral photogrammetry.
Introducing Intraoral Photogrammetry
Intraoral photogrammetry (IPG) is a breakthrough technology that combines the precision of photogrammetry with the convenience of IOS. Unlike traditional EPG systems, IPG allows clinicians to capture both implant positions and the surrounding tissue in a single scan without the need for separate images from 2 different capture devices or manual data merging. The Aoralscan Elite (SHINING 3D Dental) system uses a handheld intraoral device equipped with 2 on-board cameras, one for IOS and one for IPG (Figure 4). The system utilizes specific high-accuracy coded intraoral markers to accurately capture the spatial relationships between implants within the oral cavity (Figure 5).
The utilization of IPG for full-arch implant reconstruction begins once the implant surgery has been completed and after multi-unit abutments have been secured to each implant. A traditional intraoral scan of the tissues at the multi-unit level is acquired, followed by the placement of the specially coded horizontal scan markers onto the multi-unit abutments connected to the implants. The markers, which are 3 lengths, are designed to be easily distinguishable by the scanner, ensuring that each one is captured accurately. The scanner’s software identifies and tracks these markers in real-time, allowing it to precisely measure their positions relative to each other. This real-time capture eliminates potential errors caused by patient movement or changes in lighting conditions, which are common pitfalls in traditional intraoral scanning. Once the implant positions have been captured, the scanner defaults back to its IOS camera and moves on to capture the surrounding soft tissue, bite relationships, and adjacent teeth. This integration of hard and soft tissues into a single digital model streamlines the workflow, reducing the time and effort required to create a comprehensive digital representation of the patient’s oral anatomy (Figure 6a). The resulting model can be directly transferred into CAD/CAM software (Figure 6b) for immediate use in designing restorations, eliminating the need for separate scans and manual data alignment.
Conclusion
The popularity of full-arch implant reconstruction has increased dramatically in the last decade providing aesthetic and functional solutions for patients who are missing teeth. In addition, due to advanced imaging capabilities, clinicians have improved methods of assessing the bone to allow for simultaneous procedures including tooth extractions, bone reduction, and implant placement with immediate or early loading protocols. Currently there are analog and digital workflows that provide sufficient accuracy and passive fit to produce full-arch, screw-retained restorations in collaboration with our dental laboratory partners. Intraoral scanning full-arch implant positions have been proven to be inconsistent and often require a separate verification jig to ensure proper fit. Combination analog and digital solutions have been developed to aid clinicians achieve the required accuracy necessary to produce monolithic, screw-retained restorations. Recently, the use of EPG has been introduced to solve the problem of digitizing the positions of implants, but also requires a separate IOS to capture the soft tissue topography creating 2 datasets to be sent to the dental laboratory. IPG, described in Part 1 of this 2-part series has been introduced in a novel single device combining IOS and PG functionality while supplying the dental lab with a uniform dataset to produce the design for temporary and final prostheses. Part 2 of this series will further demonstrate this state-of-the-art technology with additional case examples.
ABOUT THE AUTHORS
Dr. Tawil received his DDS degree from the New York University College of Dentistry and has a Masters degree in biology from Long Island University. He is co-director of Advanced Implant Education (AIE). He is a Diplomate of the International Academy of Dental Implantology as well as a Fellow of the International Congress of Oral Implantologists (ICOI) and the Advanced Dental Implant Academy. He also received recognition for outstanding achievement in dental implants from the Advanced Dental Implant Academy. He maintains a general private practice in Brooklyn, NY, where he focuses on implant therapy. He can be reached via email at tawildental@gmail.com.
Dr. Ganz has published in many scientific journals for over 5 decades and contributed to 22 professional textbooks. He presents nationally and internationally on the prosthetic and surgical phases of implant dentistry. Dr. Ganz is a Fellow and Diplomate of the Academy of Osseointegration (AO), Fellow of International College of Dentists, and co-director of AIE. Dr. Ganz has been past president of the NJ Section of the American College of Prosthodontists; past board of director of Digital Dentistry Society (DDS) and the ICOI; past president of the CAI Academy; and is currently on the board of directors of the Clean Implant Foundation. Dr. Ganz maintains a practice in Fort Lee, NJ, and is director of full arch implant reconstruction in the heart of Manhattan, NY. He was recently honored for his lifetime achievements in implant and digital dentistry by the American Academy of Implant Dentistry and the DDS. He can be reached at drganz@drganz.com.
Dr. Pozzi has been in practice since 1997, specializing in oral surgery, orthodontics, and TMJ dysfunctions. He is licensed by the Italian General Dental Council of Rome and by the UK General Dental Council of London. He is a clinical researcher and professor at University of Rome Tor Vergata, adjunct associate professor at Goldstein Center for Esthetics and Implant Dentistry, Augusta University, August, Ga; adjunct clinical professor department of periodontics and oral medicine at the University of Michigan School of Dentistry; and lecturer at Harvard School of Dental Medicine, department of restorative and biomaterials sciences. He is a Fellow of AO. Dr Pozzi is widely published, and an international awards winner for his clinical research. He is the founder of the Pozzi Institute in Rome. where he has been training colleagues from all over the world. He is recognized as a global expert in digital implant dentistry and advanced technologies. He can be reached at his Instagram handle @profpozzi and his Facebook handle @alessando.pozzi.
Disclosure: Dr. Ganz receives lecture honoraria from, and is a key opinion leader for, Shining 3D. Drs. Tawil and Pozzi report no disclosures.
This article was first published online in the International Magazine of Digital Dentistry and is reprinted with permission by Dental Tribune International.
