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Inside Dentistry
June 2022
Volume 18, Issue 6

The Evolution of Guided Implant Surgery Workflows

3D imaging is the key to successful diagnosis and treatment planning

Scott D. Ganz, DMD | Isaac Tawil, DDS, MS

Although guided dental implant surgery has evolved as technology has evolved, they have not always evolved in tandem, and the evolution did not occur exactly as one may have predicted. It is generally understood that the vast number of dental implants are still being placed in a "freehand" manner and that many of the clinicians who are placing them are doing so using two-dimensional imaging, such as periapical and panoramic radiography. Yes, in 2022, clinicians are still placing implants using two-dimensional imaging, even though these modalities provide no information regarding the width or density of the bone and, due to inherent distortion factors, exhibit significant inaccuracies.

The introduction of three-dimensional imaging modalities, which began with medical grade computed tomography (CT), provided clinicians with an opportunity to visualize patients' anatomical presentations without distortions. Unfortunately, in the late 1980s and 1990s, the use of medical grade CT was limited to hospitals or large imaging centers, and the high cost to patients prevented mainstream adoption for dentistry.

The next major catalyst to enhance diagnosis and treatment planning in dentistry was the introduction of cone-beam computed tomography (CBCT) systems, which were permitted to be installed within dental offices. These machines included software that facilitated the assessment of patient anatomy and the virtual simulation of dental implants, empowering the educated clinician with a wealth of information; however, early software applications had limited tools to bring the plan from the computer to the surgical operatory.

The ability to plan implant positions based on the ultimate functional and esthetic outcome has been referred to as "restoratively driven" or "top-down" planning. Initially, an analog diagnostic wax-up was fabricated to indicate the tooth morphology and then incorporated into a scannographic template using a radiopaque material that would show up on the CT scan or CBCT scan. In this manner, the position of a simulated implant could be assessed with regard to the position of the restoration using interactive software tools. This diagnostic relationship was then transferred to a physical or "static" surgical guide to be used during the surgical intervention.

As technology continued to evolve, virtual tooth libraries were incorporated into planning software applications, and the next logical step was to export that data in the form of an STL file to a milling machine to fabricate the restoration via CAD/CAM technology. This technology also made it possible to mill the surgical guide rather than fabricate it by analog methods. However, surgical guides milled from 3D digital planning data were not readily adopted due to a variety of different obstacles, including the cost.

The next development that ignited the industry was the introduction of low-cost 3D printers for dental laboratories and practices. The use of stereolithography to 3D print anatomical models and surgical guides greatly contributed to the advancement of guided surgery protocols.

The process of "digitizing" stone casts for planning ultimately evolved into the process of merging digital data from intraoral scanning devices with the CBCT dataset to facilitate the fabrication of surgical guides using an entirely digital protocol. Furthermore, technological advances combined with increased computing power have also facilitated the development of advanced surgical modalities for guided implant placement, including dynamic navigation and robotic guidance, which are gaining in popularity.

The state-of-the-art continues to evolve, providing clinicians with improved capabilities to deliver better care for their patients. Guided surgery is undeniably more predictable than freehand placement; however, regardless of the use of static, navigational, or robotic guidance, it cannot be overstated that the underlying foundation for success is proper diagnosis and treatment planning using 3D imaging.

About the Authors

Scott D. Ganz, DMD, is the co-director of Advanced Implant Education and maintains private practices in Fort Lee, New Jersey, and Manhattan, New York. Isaac Tawil, DDS, is the founder and director of Advanced Implant Education and maintains private practice in Brooklyn, New York.

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