The term endoscopy is derived from the Greek language and is literally translated as endon (within) and skopion (to see), hence the meaning, “to see within.”1 Early endoscopists such as Hippocrates in 377 BC used primitive tube-like instruments for endoscopy. Arabs in 900 AD utilized mirrors to illuminate body cavities, and Nitze in the 1870s incorporated lenses with an incandescent platinum wire loop for illumination. All were restricted by the inability to transfer sufficient light distally into the body cavity, as well as the limited field of vision offered by the tube opening (bore).2
With major advances in the field of medicine, a breakthrough in optical quality was achieved in 1960 by an English physician, Hopkins, who created a rod lens series that led to important advancements in the field of view, magnification, and focal length of the endoscope, resulting in a clearer image. During this time period, the convergence of image bundle fibers also advanced endoscopy to smaller bore devices of 2, 3, and 5 mm.3
Later video systems credited to Mouret in the 1980s were integrated with the endoscope, and provided an enhanced image signal. By the late 1980s and early 1990s, flexible endoscopes that used fiber-optic bundles to transmit light and images were important instruments in cardiology, general surgery, gynecology, and otolaryngology.4
The widespread use of flexible endoscopes has been the catalyst for performing a number of minimally invasive surgical (MIS) procedures to remove polyps and cancerous, life-threatening lesions in the gastrointestinal tract. With orthopedic surgeons providing endoscopic medical treatment for knee surgery using arthroscopic procedures since the 1980s, the lay public became familiar with this aspect of medical care.5
Over time, both optic and video technology have advanced, with improvements in fiber optics, software processing, and video interfacing. These continuing advancements have fostered smaller bore endoscopes of 2 mm and less, further improving access into smaller cavities and anatomical structures.6
The field of endoscopy has recently expanded further with the introduction of the dental endoscope. This endoscope, with its uniquely small bore size of less than 1 mm, is ideal for use during minimally invasive dental surgical applications (MIDSA).
USING THE DENTAL ENDOSCOPE
|Figure 1. The Dental View dental endoscopic viewing system in a clinical setting.||Figure 2. Clinically, this tooth appeared to have a fracture in the coronal portion only, but when viewed with the dental endoscope it was evident that the fracture extended apically into the furcation.|
|Figure 3. Maxillary palatal groove.|
The dental endoscope viewing system (Dental View) is currently available as a diagnostic and therapeutic adjunct to the restorative dentist, endodontist, periodontist, oral pathologist, oral surgeon, otolaryngologist, and dental hygienist (Figure 1). For instance, this fiber-optic technology is beneficial for determining the etiology of an isolated area with increased probing depths and alveolar bone loss.7 This dental endoscopic viewing system provides the practitioner with high magnification (24X to 50X) and a light source via a fiber-optic illumination to allow visualization that is otherwise not possible. Figure 2 is a clinical photograph of a tooth with a fracture evident in the coronal portion, but when viewed with the dental endoscope it was evident that the crack extended apically into the furcation. In addition, residual subgingival calculus in a patient with adult periodontitis can be visualized.8 Many patients may therefore benefit from use of this device, because 7% to 15% of the adult population is affected by severe periodontitis.9 The dental endoscopic viewing system can also enhance visualization of a new carious lesion, recurrent caries, inadequate restorations in proximal boxes or class V restorations, intrafurcal fractures, anatomic aberrations, (eg, a palatal groove on maxillary lateral incisors10) (Figure 3), residual crown and bridge cement,11 oral pathologic lesions, and root fractures/perforations.
Root perforations can be diagnosed through clinical observations, patient symptoms, radiographs, or a combination of these findings.12 Here, prognosis is dependent on the size and location of the perforation. The long-term prognosis for a small perforation is good when it occurs supragingivally and can be sealed. However, the prognosis is poor when the perforation occurs in the pulp chamber floor or a furcation.13
|Figure 4a. The dental endoscopic probe in use.||Figure 4b. Illustration (left) of dental endoscopic image showing burnished calculus on palatal line angle of a tooth.|
Once the etiology is determined with the endoscope, then the practitioner can use the enhanced visualization and, with curettes, files, scalers, and explorers, treat the problem with either a surgical or nonsurgical approach (Figures 4a and 4b).
One of the most important components of MIDSA is for the clinician to obtain confirmation of the tentative diagnosis or modify the diagnosis based on newly visualized findings. This will help in the selection of an appropriate course of therapy.
For example, with regard to a standard crown and bridge case, it is paramount that, before and after final cementation of individual crowns or fixed partial dentures, the clinician has a high degree of confidence that the restoration is ideally adapted to the prepared abutment, whether it is a natural tooth or dental implant. Assessing the final restoration for a precise fit is thus a common but critical task.
While the use of a radiograph to evaluate fit may be beneficial, this method can only be considered a secondary measure because the amount of information provided is limited. The primary shortcoming of a conventional radiograph is that it provides a two-dimensional image of a three-dimensional object. In addition, the ability to detect marginal discrepancies is primarily dependent on the angle used to obtain the radiograph. Although discrepancies detected in a radiograph should be addressed, the lack of radiographic findings does not necessarily mean the restoration fits ideally.14 This is important because research suggests that both maxillary and mandibular molars with crowns and proximal restorations are more likely to have furcation involvement than molars without restorations.15 The proper evaluation of a casting or restoration for a precise fit must incorporate the clinical inspection of the margins by both visual and tactile means. The margins should certainly be checked with a dental explorer. But without the use of the dental endoscope, the visual inspection is limited to supragingival areas. With the endoscope, the subgingival margins can be viewed while simultaneously being checked with an explorer. This eliminates doubts concerning the proper fit of the casting or restoration.
|Figure 5a. Maxillary bicuspid with a vertical fracture.||Figure 5b. Illustration (left) of captured dental endoscopic image providing diagnostic confirmation of the vertical root fracture.|
The endoscope can also provide diagnostic confirmation of a tooth with a suspected fracture. The clinician can use the endoscope to visualize the root surface to determine if the root is or is not fractured (Figures 5a and 5b). This clarification and diagnostic information can aid the clinician in treatment planning. There are also legal ramifications, as extracting a tooth thought to have a fracture, but without confirmation after tooth removal, may cause considerable distress to the patient16 because the tooth may not have had a hopeless prognosis. Another benefit of the dental endoscope is patient explanation. An example is a patient who presented with excellent oral hygiene, but the gingival tissues were inflamed, bled upon probing, and had clinical probable pocket depth of 4 to 5 mm. The patient reported having professional cleanings every 6 months. She reported bleeding when flossing for the past several months. The radiographic examination demonstrated only slight alveolar bone loss. The patient stated that her dentist mentioned that she had lost bone around her teeth due to periodontal disease. The intraoral exam revealed that this patient had numerous old amalgam fillings and porcelain-fused-to-metal crowns in the maxillary anterior region that extended several millimeters below the gingival margin.
It was concluded that this patient had inflammatory periodontal disease, related in large part to plaque accumulation in association with poor crown and amalgam restorations. Wang et al17 reported that periodontal attachment loss is greater adjacent to restored subgingival tooth surfaces when compared with nonrestored tooth surfaces, possibly because the restored surface allows greater accumulation of plaque in the subgingival environment. Unfortunately, it was inferred that the patient was at fault by not performing appropriate daily plaque control. As a result, the patient felt confused and discouraged. It was then explained to the patient that it was important to both determine and illustrate the nature of the problem.
|Figure 6. Illustration (left) of captured dental endoscopic image indicating residual burnished cement at the crown-tooth interface.|
Therefore, the dental endoscope was utilized to visualize the abutment teeth and proximal areas with subgingival restorations. The endoscope revealed that these old restorations had poor marginal adaptation and were no longer adequate. Instead, they appeared to be harboring bacterial plaque, calculus was forming, and in a few locations there appeared to be recurrent decay. Also, when the subgingivally located crown margins were viewed with the dental endoscope, there appeared to be residual cement at the crown-tooth interface (Figure 6).
As noted, molars with crowns or proximal restorations that extend below the gingival margin have a higher prevalence of furcation involvement and greater attachment loss than non-restored molars or molars with supragingival restorations. This occurred even though regular maintenance was performed.17 Clearly, the poor marginal adaptation was associated with increased plaque accumulation, more inflammation, and ultimately increased attachment loss.
With visualization, the etiology as described above was demonstrated to the patient.18 Treatment for this patient included scaling and root planing, followed by re-evaluation of the periodontium 4 to 6 weeks later. Then, as probing depths were 3 mm or less, and bleeding upon probing was not observed, the patient was encouraged to see her restorative dentist for replacement of the inadequate restorations.19 Treatment also included positive reinforcement for the patient by praising her excellent home care efforts.20 The importance of following through with the restorative treatment plan was also emphasized.
These clinical scenarios are more the rule than the exception. With the use of the endoscope, generally inaccessible anatomic considerations can be observed,21-24 diagnosis can be enhanced, and treatment planning can be improved.
|Figure 7a. Dental endoscope being used to evaluate a periodontal abscess.||Figure 7b. Illustration (left) of dental endoscopic image indicating the presence of burnished calculus on the root, which was related to the clinical periodontal abscess.|
In addition, a study published by Gher and Vernino in 198025 demonstrated that even the most experienced clinicians were able to achieve removal of calculus on root surfaces only 68% of the time in furcations (Figures 7a and 7b). Similar results were noted by Caffesse et al26 and Buchanan and Robertson,27 who reported that surgical access for root debridement resulted in less residual calculus than with closed scaling and root planing, particularly in deep sites. It is important to note that even with surgical access, these studies found that it was impossible to completely clean the inside surfaces of furcations or the anatomic grooves found on the inner aspects of the mesial and distal roots.28 In these cases, visualization will be very helpful.
It is important to note that detection of subgingival calculus is a genuine clinical problem in periodontics. In one study,29 three calibrated examiners evaluated teeth after scaling and root planing. Only 18.8% of the root surfaces were found to have calculus. Upon macroscopic examination following extraction, these teeth demonstrated residual calculus on 55% of the surfaces examined. The findings of this study illustrate the difficulty in determining the presence of residual calculus by clinical examination with an explorer and periodontal probe. These findings underscore the need for improved approaches to evaluate root surfaces for the presence of bacterial deposits.
|Figure 8a. Mandibular molar with severe bone loss in the furcation.||Figure 8b. Captured dental endoscopic image (left) and illustration (right) of the dental endoscope being used during periodontal surgery to visualize the extent of bone loss.|
Endoscopic technology has been utilized successfully for many years in medicine and is now part of the dental practitioner’s diagnostic and treatment armamentarium. Just as in the field of medicine, this technology has proven advantageous by increasing the clinician’s diagnostic and therapeutic capabilities, and often can provide a means of confirming the clinical diagnosis. The magnified visualization provides a tool for the dental practitioner to view in “real time” the affected area (Figures 8a and 8b). In addition, the results of therapy can be evaluated more effectively as compared with traditional tactile methods.
The authors would like to extend special appreciation to Val Montegrande and Company (Irvine, Calif), and Kenn Trezek (Atlanta, Ga) for their digital imaging expertise, and to Marie Whisnant (Atlanta, Ga) for her assistance in the preparation of this manuscript.
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Dr. Kurtzman has attained the status of Fellow in the Academy of General Dentistry. His general practice is located in Marietta, Ga.