Enodontics provides an exciting frontier. New conventional endodontic techniques as well as surgical advancements in materials and visualization have elevated the standard of care in this specialty. As the profession begins to view endodontic surgery as a microsurgical procedure, it will demand good visualization in this area as well.
With this need for increased visualization in endodontics, there is a constant search for better instruments and techniques to meet this demand. This has led to the exploration of endoscopy. As you know, medical endoscopy uses a rod lens, light source, camera, and monitor to explore a body cavity (Figure 1). The rod lens is the primary and most important instrument used in this system (Figure 2).
The use of the medical rod-lens system in endodontics was, at first, an advancement in visualization over the microscope. But after many clinical trials, the rod-lens system proved to be bulky, heavy to handle, and difficult for accessing different angles within the oral cavity. The original medical endoscope's monitor, camera, and light source also proved to be difficult to maneuver in dental operatories.
Orascopy involves using the Orascope, a modified medical endoscope, for treatment in the oral cavity. It uses fiber optics, making the instrument lightweight and flexible. In the past, fiber-optic imaging provided superior ergonomics but suffered from poor image quality. But the Orascope uses a unique lens design combined with a digital image processing system in the camera, allowing the fiber optics to surpass the image quality of the medical rod lens. The device is manufactured by FiberDent Corp. (Ann Arbor, MI).
The system's 1.8-mm diameter universal probe has 30,000 fibers and is used for conventional and surgical endodontics (Figure 3). Its 0.9-mm diameter universal probe has 10,000 fibers and is used to visualize within a canal (Figure 4). The fiber-optic bundles are made up of light fibers and image fibers. These thousands of fibers must be exactly parallel with each other or the resulting image will be distorted on the monitor.
Orascopy provides visualization the endodontic microscope can't (Figure 5). The microscope's field-of-vision is fixed and can't readily be adjusted to view different angles of an endodontic treatment field. This creates a struggle for the operator when lining the microscope's field-of-view with the mirror, which would still produce an indirect image of the conventional or surgical site.
Orascopy, however, can easily be adjusted to view any angle. The depth-of-field and focus with the Orascope are very similar to the human eye. Focus adjustments are minimum, and the depth-of-field is consistent. In contrast, the microscope has to be refocused when a power setting is changed or the patient moves. The depth-of-field with the microscope is also greatly decreased when magnification increases.
The Orascope enables a dentist to work from the monitor (Figure 6) rather than struggle to adjust the ocular piece and focus on a micromirror. This allows for better magnification and clarity of the operating field and enhanced ergonomics for the operator. No special instruments or procedures are required. Microsurgical instruments work well in Orascopy.
Even though an Orascope appears very similar to an intraoral camera, it isn't. Intraoral cameras are primarily used for patient education, case presentations, and documentation. Orascopy is used to provide treatment, has much better monitor resolution, and uses morphologic algorithms to "clean up" the screen images. A clinician would never use an intraoral camera for a microsurgical procedure.
The sterilization concerns in Orascopy stem from the breakdown of epoxy that holds the lens and fibers together. Dental autoclaves cool down too quickly for the Orascope's fiber optics and cause a breakdown of the epoxy. The use of fiber optics or a rod lens with dental autoclaves would be limited to 50 to 70 uses. The autoclaves used in hospitals have a more controlled cool-down phase. But currently the costs for these devices are prohibitive in a dental office.
Physicians who do in-office endoscopic procedures have the same sterilization limits. As an alternative, physicians soak their instruments in a glutaraldehyde-type solution. This can take up to 10 hours, and there is still a breakdown of the epoxy from the caustic chemicals. But the use of clear plastic sleeves with a custom shield around the lens provides a barrier protection approved by the FDA and extends the fiber-optic system's life by hundreds of uses.
Orascopy in endodontics allows not only better visualization but also an understanding of endodontic etiology. The ability to visualize within a canal or at a surgically resected root gives dentists a better success rate with endodontic treatment because they have a better understanding of what they're treating.
Dr. Bahcall is assistant professor and chairman of the Department of Endodontics at Northwestern University School of Dentistry in Chicago. He is codirector of the Orascopy Institute also in Chicago.
Dr. Barss is assistant professor in the Department of Endodontics at Northwestern University School of Dentistry and codirector of the Orascopy Institute. He is also a PhD fellow in the Department of Oral Biology at Northwestern University.
Bahcall J, Barss J. Orascopy: endodontics' vision for the new millennium. Dent Today. 1999;18(5):68-71.