Dental Endoscope – Endoscopy is the inspection of body cavities and organs using an endoscope, which consists of a tube and optical system with a high intensity light. The image captured by the endoscope camera is projected onto a video monitor for viewing. Since the introduction of modem endoscopy by Hopkins in the 1960s, endoscopic visualization for diagnosis and surgical therapy has become a standard of care. In medicine, diagnostic and surgical endoscopic techniques have continuously been refined, for use in various branches of medicine.
With the introduction of microsurgical principles in the 1990s, the field of endodontic surgery has made continuous and substantial progress. The root-end cavity preparation has been simplified and optimized by means of newly developed surgical micro-instruments.
However, the successful outcome of endodontic surgery depends to a large extent on accurate intra-operative diagnostics. Conventionally, micro- mirrors (retro-mirrors) and microprobes have been used for this purpose. The surgical microscope has been used to enhance visibility during dental procedures and for last many years there has been a continuous search for enhanced visualization of the surgical field.
The endoscope and video system is used in modem dentistry to further enhance the visibility and understanding of the Endodontic procedure. This system is used for the periradicular surgery (root-end resection), surgical perforation repair, root resection, and root fracture evaluation.
The equipment that makes up the endoscope system is the scope, a camera coupler, a video camera, fiber-optic cables to carry light from a halogen or xenon light source, a camera control unit, a video recorder and or a video printer and monitor on which to view the procedure.
While the video recorder and printer are not necessary for operation of the endoscope, they are useful for documentation and patient education. Furthermore, an endodontist can send a referring dentist a color print of a completed surgical procedure instead of a radiograph.
All components of the endoscope and video system are placed on a multimedia cart. This cart is fully maneuverable from room to room and can be positioned independently in the surgical room for optimal viewing.
The endoscopic camera and the camera control unit are the main components of the system. The surgeon can directly operate focusing and zooming with two different rings located in front of the camera head. The camera head has an integrated instrument coupler, to which the endoscope’s ocular is inserted. The endoscope (rod-lens system) is a 6 cm long and 3 mm wide telescope with a viewing angle of
70 degrees. This permits the surgeon to access difficult surgical sites.
Stability of the scope itself is important. A variety of sheaths can be employed to provide rigidity, support and stabilize movement. Sheaths come with a variety of working ends. The working end of the scope can be obtained in a variety of angles. The 300 scope is the most useful angulation for endodontics.
The scope is held away from the operating field, thus giving the endodontist unlimited freedom of movement and access to a tooth. The scope can be held in position by the sheath and rotated 360° to completely view all aspects of the field.
Micro-openers and Micro-debriders are very useful in hard to reach areas of posterior teeth. The endoscope provides light and magnification and the slender offset handles of the Micro- openers and Micro-debriders allow for an unobstructed view of the access opening and canal orifices.
The Micro-opener combines the capabilities of an explorer with the capabilities of a K-file making it easier to locate and penetrate calcified orifices and canals. The plastic handles provide a light tactile sense and they are ISO colour-coded and can be sterilized. They are available in sizes 10 and 15 with .04 and .06 tapers and have 7 mm K-type flutes.
The Microdebriders are ISO-sized Hedstrom type instruments with a .02 taper and 16 mm cutting flutes in sizes 20 and 30 with ergonomic handles similar to the Micro-openers. Together these two flexible, stainless steel instruments give improved access in hard to reach teeth while maintaining the feel of standard hand instruments.
During procedures involving high-speed rotary instruments, the tip of the endoscope can become covered with debris and the video picture may appear blurred. Saline or sterile water in a syringe is used to rinse away the debris and clear the viewing field on the monitor.
After use, the sheaths can be placed in an ultrasonic cleaner to remove debris and sterilized in an autoclave. The scope cannot be placed into an ultrasonic cleaner but can be cleaned and sterilized by chemicals. Autoclavable scopes are available at higher costs. The camera lens head can be cleaned with a mild soap and distilled water and chemically sterilized. It is best covered with disposable plastic tube wrap during use, in order to keep it sterile and free of debris.
SETUP IN THE SURGICAL ROOM
In endoscopy, use of a monitor instead of viewing through the ocular is highly recommended. This allows the surgeon as well as the whole surgical team to view the surgery on the monitor. Teaching and instructing students and personnel is as simple as possible. In addition, the surgeon maintains a correct posture when working from the monitot The monitor should be placed opposite the surgeon at the level of the patient’s lower leg region.
For aseptic reasons, the video camera and the camera cable are packed in sterile covers and are subsequently connected to the ocular of the endoscope. Both the light cable and the endoscope can be sterilized (autoclavable up to 134°C). The surgeon holds the endoscope and camera in one hand with a pen grasp. In this way, the operator can readily adjust the viewing angle and the position of the telescope lens. Surgery is more efficient when the surgeon, not an assistant, guides the endoscope.
Good hemorrhage control is essential for obtaining high-quality pictures from the surgical field. In addition, the endoscope lens must be cleansed regularly with an anti-fogging solution. Direct contact with rotating or vibrating instruments must be avoided, because these may damage the lens.
CLINICAL APPLICATIONS OF ENDOSCOPE IN DENTISTRY
An endoscope is extremely useful in various surgical procedures including apicoectomy, retrograde fillings of the root end and location and repair of perforations and internal and external resorptive defects. The endodontist can visualize the access opening, canal orifices, the canal interior, fractures, resorptive defects and surgical sites, with the help of endoscope.
The endoscope aids in several aspects of periradicular surgery. Following flap reflection and fenestration of the buccal cortical plate, the endoscope is placed near the surgical site for inspection of the root apex and any denuded root surface. At this stage, the presence of irregularities such as lateral or furcational canals, perforations, and extraneous material should be assessed with the endoscope. In addition, root or crown-root fractures must be ruled out, because such findings directly affect the progress of the surgery.
After root-end resection, the cut root face as well as the removed apical fragment should be inspected with the endoscope. Vital tissue staining with methylene blue dye is recommended for periradicular diagnostics and tissue differentiation. The dye (concentration 2%) is applied for 5 to 10 seconds to the surgical site with a small gauze pad. The dye is then rinsed away with saline.
Methylene blue stains not only organic tissue components but also non- instrumented or non-obturated root canals at the cut root face. This allows the surgeon to observe the number and morphology of canal openings as well as any isthmus tissue that may be present. In addition, staining with methylene blue permits the detection of oblique or vertical root fractures. Staining the outline of the periodontal ligament allows verification that the root has been resected entirely with respect to its cross- section.
During root-end cavity preparation, the endoscope aids in assessment of the extension, direction, and depth of the retro-cavity. Ideally, the preparation should follow the original path of the root canal, but it should also include any isthmus tissue or lateral perforations.
Following preparation, the cavity walls are inspected for remaining gutta-percha or sealer, and the cavity margins are examined for cracks and chipping. These should be eliminated by smoothing before placement of the root-end filling. This permits better marginal adaptation of the restoration, providing a tighter retrograde seal.
Following root-end obturation, the filling should be inspected for any deficiencies. Before wound closure, the endoscope is used to examine the bony crypt and to verify that no extraneous material is left behind.
There are many advantages of using the endoscope. They are:
(1) It provides excellent illumination and magnification. The direct illumination of the field, brightness with no loss of resolution, makes possible the viewing of earlier inaccessible areas.
(2) Angled optics permits the surgeon to look around the corner. The seeing around corners (30° scope) and the endoscope is easily positioned 0.5-10 mm from the working field.
(3) There is a short learning curve, no eyestrain, freedom of body movement and no need for the use of a mirror.
(4) Adjustment of the viewing angle is rapid and easy.
(5) It allows direct viewing; no mirrors are required.
(6) Its depth of field and focus are similar to the ability of the human eye to make visual adjustments.
(7) Magnification is 10-25 x and the endoscope is cost-effective as compared to the microscope, depending upon the equipment desired.
(8) The Endoscopy is a readily transportable, versatile, and expandable system. The endoscope is easily transportable on a cart and also can be used as an intraoral camera.
(9) Assistants can see a full view of the operating field on the television monitor.
(10) Either the endodontist or the assistant can hold the scope, depending upon the side of the mouth being treated.
(11) The endoscope and light cable can be sterilized.
(12) Because of its small size, the technology is not intimidating to patients.
(13) The learning curve is short.
There are some disadvantages or the limitations of the endoscope, some of which are as follows:
(1) The operating field is not seen in three dimensions.
(2) Because each scope has to be sterilized between patients, several scopes are needed.
(3) Inadvertent damage to the quartz rods inside of the scope can occur. This is most often caused by the end of the scope being in close proximity to the operating field. Burs, curettes and retractors can scratch the scope. If a sheath is not used to cover and protect the rod of the scope, the rod can be bent and the quartz rods cracked with loss of resolution.
(4) A repeated cleaning of the lens is required because of fogging or soiling with blood, tissue, or cooling agent.
The demand for use of optical aids for diagnosis or therapeutic visualization will grow in the near future in dentistry. The increasing number of publications on the use of the surgical microscope in dentistry, the marketing of such equipment, and the offering of continuing education courses indicates the expanding interest of the dental community in this new technology. Therefore, the expanded use of the endoscope complements the gaining popularity of applying magnification techniques in dentistry.
The future for endoscopy is very bright. High-resolution flexible scopes are under development. With these flexible scopes, the endodontist will be able to view the internal aspects of a canal and examine canal cleanliness, locate accessory canals, perforations and resorptive defects.
Furthermore, after the development of suitable software, which will piece 2 dimensional images to create a virtual 3D image, this technique will become an asset for an endodontist. We can visualize that in next step of development, the endodontic surgical and nonsurgical procedures performed by robots with the help of endoscopes, may be possible in the near future.