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Asian Pac J Dent 2011; 11: 35-43.

A preliminary study on the usefulness of fiberscope for
subgingival periodontal treatment
Kazuyuki Kobayashi, DMD, PhD, Yasushi Yamazaki, DMD, PhD, Toshiko Ozawa, DMD,
PhD, Mami Tsuchida, DMD, PhD, and Takashi Arai, DDS, PhD
Department of Periodontics and Endodontics, Tsurumi University, School of Dental Medicine,
Yokohama, Japan
Purpose: Direct, real-time visualization of subgingival area may improve the efficiency of subgingival treatment.
The purpose of this study was to evaluate the usefulness of the fiberscope (FS) for subgingival periodontal
treatment.
Materials and Methods: The original jaw model in which the artificial teeth were uniformly coated with nailenamel was attached to a simulator head. The experimental teeth were painted on the root surfaces of #12, #13
and #14, and in the furcation of #46. Three types of the FS (3,000 pixels, φ1.0 mm) with working or irrigation
channel were used. The operators were eight dentists (four experienced and four beginning clinicians for using aFS). The experimental teeth were performed scaling and root planing (SRP) with and without FS. Furthermore,
the experimental part which are difficult to adapt periodontal instruments were irradiated with Nd:YAG laser(100 mJ, 15 pps) using the FS, only by the experienced clinicians. Then each root surface was observed toanalyze the residual nail enamel.
Results: The residual rate in FS group was significantly lower than that in non-FS group on the labial root
surface of #12 and in the furcation of #46 (p<0.05). Also, it was possible to remove nail enamel by Nd:YAG
laser irradiation using the FS.
Conclusion: The results suggest that the application of FS for subgingival periodontal treatment leads to better
outcome in comparison with conventional periodontal treatment without FS.
(Asian Pac J Dent 2011; 11: 35-43.)
Key Words: fiberscope, Nd:YAG laser, root planing, scaling, subgingival periodontal treatment

Introduction
Nowadays many endoscopic systems with fiberscope (FS) are widely used in the field of medicine for clinicaldiagnosis and treatment.1,2 However in dentistry, this system has not been so popular as yet. Numerous studies
have shown that subgingival plaque and calculus are related to destructive periodontal disease.3-6 Therefore, theremoval of bacterial plaque and calculus is an important aspect of all periodontal therapy.7,8 However, theinability of the clinician to scale and plane the subgingival root surface completely has been repeatedly
demonstrated.6,9-12
Scaling and root planing (SRP) are important methods of periodontal therapy which are difficult to master.
The difficulties in accomplishing proper debridement increase with increasing depth of periodontal pocket, thepresence of root fissure, root concavity and furcation in the subgingival area. But, direct, real-time visualizationof subgingival hard and soft tissue may improve efficiency of subgingival treatment.

So, we have beendeveloping an original endoscopic system with FS since 1996 to employ it in clinical dentistry, especially forperiodontics and endodontics.13,14 This system is very useful for observing the subgingival root surface incarrying out periodontal treatments. The purpose of this study was to evaluate the usefulness of the FS for
subgingival periodontal treatment.

Materials and Methods
Original jaw model and experimental teeth
The original jaw model (Koken, Tokyo, Japan)15 in which the artificial teeth were uniformly coated with a35

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layer of nail enamel was attached to a simulator head.

This original jaw model (Fig. 1) can allow thefundamental examination of periodontium such as probing pocket depth (PPD), tooth mobility and so on. Some
degree of bone resorption is also observed on this model as indicated in the attached X-ray photograph (Fig. 2)that reflects the bone resorption of this model. In addition, morphological abnormalities of the teeth andadjacent soft tissues, such as high frenal attachments, tension ridge, festoon, cleft, lingual groove (#12) andenamel projection (#46) are also reproduced on it (tooth numbering: FDI Two-Digit Notation). Lower left sideof the original jaw model represents normal gingiva and alveolar bone. Upper left side presents abnormal
gingiva and normal alveolar bone (relative pocket). Right side presents some degree of bone level resorption
and abnormal gingiva (absolute pocket). The experimental teeth were painted with nail enamel on the labial andpalatal root surfaces of #12, the distal root surface of #13, the mesial root surface of #14 and in the furcation of#46 (Fig. 3). Table 1 shows PPD and attachment level (AL) of the original jaw model.
Table 1. Probing pocket depth (PPD) and attachment level(AL) of the original jaw modelFig. 1. The original jaw modelFig. 2. X-ray photograph presenting periodontal bone resorption

Fig. 3. The painted parts with nail enamel on the experimental teeth

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Fig. 4.
Three types of FS(A) Form of needles(B) Cross-section of needles

Fig. 5. Endoscopic system

Fig. 6.
FS findings on insertion into theperiodontal pockets(A) The distal root surface of #13(B) The furcation of #46

Endoscopic systems with FS
The FS (Solid Scope FT-711, Denics International, Tokyo, Japan) consists of image fibers (3,000 pixels)
together with two light guides and a working or irrigation channel of 0.3 or 0.45 mm in inner diameter for37

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irrigation with water and introduction of instrument. Gradient index lens was used as the lens of the FS. The
lens of the FS has a nominal 70° field of view. The FS is adjusted so that a field between 0.8 mm and about 1.5
mm is in focus. And the magnification is approximately 30x in a monitor, depending on the distance of theobject from the tip of the FS. Three types of needles with an outer diameter of 1.0 mm were used in this study.
Type A was straight. Then, type B had a gradual curvature and type C with a more acute curvature. It is possible
to insert a fine laser fiber and a special file through the working channel of Type A and B. A protect shell, which
is a gingival retractor was added to the FS of Type A only. The protect shell was designed to avoid the fractureof FS when inserting into the pocket. This device also holds the gingival tissue away from the tip of the FS,
providing a clear view of subgingival area. The diameter of protect shell is 1.6 mm. The tip of the FS and thisprotect shell is made of stainless steel (Fig. 4).

The other endoscopic system (Dr. Comscope, Denics

International, Tokyo, Japan) (Fig. 5) consists of an imaging unit, a color video monitor and a video recorder tocatch the monitor image in real-time (Fig. 6).
Subgingival application for SRP
The operators were eight dentists consisting of four experienced and four beginning clinicians for FS use. The
operators were instructed to treat experimental teeth only. At first, the experimental teeth were treated withconventional SRP (non-FS group). A new set of experimental teeth, which replaced treated teeth from thenon-FS group, were treated with SRP using the FS (FS group). The operators performed SRP with Gracey
curettes (1/2, 5/6, 9/10, 11/12, 13/14) and universal curettes (LM-Instruments, Parainen, Finland).

Eachtreatment was carried out within 30 minutes. Then each root surface was analyzed using computerized imaging
NIH (National Institutes of Health) IMAGE soft to assess the residual rate of nail enamel. The residual rate ofnail enamel is expressed by means of the following formula. The residual rate of nail enamel (%) =The residualarea of nail enamel after subgingival treatment /the preoperative area of nail enamel x100.
Subgingival application of Nd:YAG laser
For the experienced clinicians for using a FS, after replacing the treated teeth of #12 and #46 for new
experimental teeth, the palatal root surface of #12 and the furcation of #46 were irradiated with Nd:YAG laser(Denics Laser Nd: Compact, Denics International, Tokyo, Japan) using the FS. The laser irradiation (100 mJ, 15
pps: 318.47 J/cm2) through an optical fiber (φ200 µm) was performed under water irrigation. The optical fiber
into FS was inserted into the periodontal pocket and moved up and down in order to irradiate the root surface as
evenly as possible. Then each root surface was evaluated for the residual nail enamel.
Statistical analysis
The mean ± SE for residual rate of each group was calculated, and then the residual rates of nail enamel innon-FS and FS groups, the residual rate of nail enamel in non-FS and FS groups for the experienced and the
beginning clinicians were evaluated. Data were analyzed with unpaired t-test at a level of significance of 5%(p<0.05).

Results
Fig. 7 shows the residual rates of nail enamel in non-FS and FS groups. The residual rates of nail enamel(non-FS group; FS group) were as follows: labial surface of #12 (29.84±5.26%; 12.97±3.81%), palatal surface of#12 (23.26±10.14%; 16.34±11.73%), distal surface of #13 (3.98±2.15%; 2.34±1.15%), mesial surface of #14(0.22±0.13%; 7.37±5.18%), and furcation of #46 (28.12±4.49%; 10.64±6.05%). The residual rate in FS group38

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was significantly lower than that in non-FS group on the labial root surface of #12 and in the furcation of #46(p<0.05, n=8).

Fig. 7. The residual rates of nail enamel in non-FS and FS groups

Fig. 8. Each residual rate of nail enamel in non-FS and FS groups between the experienced and the beginning clinicians forusing the FS

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Fig. 8 shows each residual rate of nail enamel in non-FS and FS groups for the experienced and the beginning
clinicians. For the experienced clinicians, the residual rates of nail enamel (non-FS group; FS group) were as
follows: labial surface of #12 (34.42±6.69%; 12.91±3.82%), palatal surface of #12 (9.13±2.85%; 1.56±0.70%),
distal surface of #13 (0.91±0.64%; 2.30±2.17%), mesial surface of #14 (0.29±0.22%; 0.76±0.72 %), andfurcation of #46 (24.69±6.99%; 14.14±11.30%). The residual rate in FS group was significantly lower than thatin non-FS group on the labial and palatal root surfaces of #12 (p<0.05, n=4).
On the other hand, for the beginning clinicians, the residual rates of nail enamel (non-FS group; FS group)
were as follows: labial surface of #12 (25.26±8.38%; 13.03±7.30%), palatal surface of #12 (37.40±18.40%;
31.12±22.27%), distal surface of #13 (7.06±3.84%; 2.38±1.20%), mesial surface of #14 (0.15±0.15%;
13.98±9.78%), and furcation of #46 (31.55±6.13%; 7.14±5.91%).

The residual rate in FS group was

significantly lower than that of non-FS group in the furcation of #46 (p<0.05, n=4). Also for the non-FS group,
there was no significant difference in the residual rate of nail enamel between experienced and beginning
clinicians. For the experienced clinicians, it was possible to remove nail enamel of root surfaces completely by
Nd:YAG laser irradiation using the FS (Fig. 9).

Fig. 9. Observation of the root surfaces by Nd:YAG laser irradiation using the FS(A) FS findings on the palatal root surface of #12 and the furcation of #46 L: Laser fiber N: Nail enamel(B) Stereoscopic findings on the palatal root surface of #12 and the furcation of #46

Discussion
Plaque and plaque products are generally known to constitute the primary causative factors in the etiology of
periodontal disease.3-6 Therefore, it is important that plaque and calculus are removed from the surfaces of theaffected teeth in periodontal therapy.7,8However, there are many reports demonstrating limitations of40

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subgingival treatment, because it is very difficult to adapt periodontal instruments to root surfaces and to usethem exactly in deep periodontal pockets.6,9-12 Waerhaug6 stated that reformation of junctional epithelium byremoving subgingival plaque on extracted human teeth after scaling. As a result, reformation of junctional
epithelium occurred in 83% of cases with periodontal pocket measuring less than 3 mm, because subgingival
plaque removal was done. But reformation of junctional epithelium could be observed only 11% at a periodontal
pocket deeper than 5 mm, because removal of subgingival plaque was difficult. This is in agreement with
Rabbani et al.,9 who evaluated the effectiveness of subgingival SRP related to the depth of pocket. Results of thestudy demonstrated a high correlation between the percent of residual calculus and probing depth. Pockets lessthan 3 mm were the easiest sites for SRP, probing depths ranging from 3 to 5 mm were more difficult, andpockets deeper than 5 mm were the most difficult.
Using the FS for subgingival treatment provides direct, real-time visualization and magnification of thesubgingival root surface and may provide the clinician with the ability to locate and evaluate the extent andnature of subgingival root deposits. The purpose of this study was to evaluate the usefulness of the FS for
subgingival treatment in deep pockets.
In this performed sites, PPD of the original jaw model was more than 5 mm and the residual rate of FS group
was lower than that of the non-FS group. Therefore, this result suggested that the application of the FS for
subgingival SRP leads to better outcome in comparison with conventional SRP without FS.
But, on the mesial surface of #14, the residual rate of FS group was high. This result is caused by highresidual rate of FS group for the beginning clinicians. Although the subgingival root surfaces for the beginning
clinicians were observed by the FS, due to unskilled handling, they may have mistaken that the nail enamel had
been removed. This result suggested that the beginning clinicians should practice clinically to master thetechnique of FS.
The dental endoscope (Perioscopy, Dental View, CA, USA) developed by Stambaugh et al.16-18 is very useful
FS system (24x to 46x magnification, 10,000 pixel waveguide fiber, vision field 53 degrees) for periodontal
treatments. A fixed, fused fiber optic bundle, less than 1 mm in diameter, was coupled to an active matrix
LCD-TFT flat panel video monitor for viewing by the clinician. A bilumen sheath was designed to provide
irrigation of the sulcus and a sterile barrier between the patient and the fiber bundle. Standard dental curets andultrasonic scalers were adapted for the instrumentation aided by the endoscope. It is possible to irrigate withwater during treatment. Rinsing with water was essential to obtain a clear view without blood or detached softand hard tissue obstruction and to differentiate between soft and hard tissue, because small soft tissues move
during the flushing process. But this system does not have a working channel. We have been developing an
original endscopic system with FS to employ it in clinical dentistry, especially for periodontics andendodontics.13,14 Medical endoscope technology was modified for the application to the dental environment.
Till now, the FS can work with other instruments when sufficient space exists in the lesion area. However, caremust be taken not to damage the thin FS with these instruments, which is a difficult task. To overcome thisdifficulty, the FS was designed with a working channel that not only rinsed with water but also allow the
introduction of instruments such as a fine laser fiber and an especial file.
The Nd:YAG laser has a wide spectrum of application in the dental field. Nd:YAG laser has been reported toreduce the amount of subgingival bacterial flora.19-22 And its application has been investigated for periodontal
therapy.19-26 Optical fiber of Nd:YAG laser is very flexible and its diameter is small. Therefore, it is possible to41

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insert a optical fiber through the working channel. These were the reasons for choosing Nd:YAG laser. The aimof Nd:YAG laser irradiation was to improve the efficiency of periodontal treatment by detoxification of root
surface and vaporizing granulation tissues. For several clinical cases, the FS has already been tried with aworking channel in which a Nd:YAG laser was inserted for treatments. As a result, good operational views wereobtained during the laser irradiation. In this study, the palatal root surfaces of #12 and the furcation of #46, areas
posing a challenge to adapt periodontal instruments to the root surfaces, were irradiated with Nd:YAG laserusing the FS. And it was possible to remove nail enamel completely by Nd:YAG laser irradiation. This result
suggested that Nd:YAG laser irradiation using the FS can improve subgingival periodontal treatment efficiency.
It has been reported that the thermal effects on pulp tissues are dependent on the degree of energy absorptionof the lased tissue, and the wavelength and energy densities of the laser used.27-29 In our study, the laser
irradiation was performed under water irrigation and the optical fiber was moved up and down in order toirradiate the root surface as evenly as possible using a FS. Thus, it seems that the energy density and irradiation
method in this study may have been safe and was not high enough to cause tissue or pulpal damage.24,30
However, the Nd:YAG laser irradiation, due to the nature of its wavelength, can penetrate more deeply than othertypes of laser irradiation. Therefore, further research will be needed to clarify this problem.
In this study, the surgeons consisted of eight dentists, who were divided into four experienced and four
beginning clinicians for using a FS. The experienced clinicians have been practiced for more than 10 years, andthe experience of using a FS was 7 years or more. However, at present, there are only four experts for using FS
in our department, because this system has not been disseminated among the dental profession. So, it isexpected that the number of experts may increase in future.
The fiber is placed in a rigid tube of stainless steel with a small diameter to be inserted in various locations.
Therefore, if unnecessary pressure is exerted against the hard tissue such as tooth and bone during subgingival
treatment, it may bend and fail. Also, the fiber and some parts of these instruments must not be subjected to hightemperatures. Hence, these instruments may fail if sterilized using an autoclave. Therefore, the instruments
should be sterilized only by chemical agents such as glutaraldehyde or ethylene oxide gas.
In the clinical setting, FS is very useful for observing the periapical tissues and root surfaces, when we
perform endodontic and periodontal treatment. It is possible to insert through the fistula, root resorption,
amalgam retroseal, perforation, root fracture etc may be observed on the monitor during treatment. On the other
hand, in periodontal pockets, the smallest deposit of residual calculus, along with furcations and root anatomy,
inflamed soft tissues, perforation, root fracture, subgingival caries, open crown margin and so on may beobserved on the monitor. In addition, those recorded image can be used for explanation to patients, as well as fora discussion of diagnosis after examination. This FS system is useful not only for explanation and diagnosis but
also for operative procedures.
Furthermore, the FS can be utilized through subgingival pockets, sinus tracts or a minimal intervention
without the need for raising surgical flaps to observe the root surface, periapical tissue and foreign materials
before, during and after the treatment. The system requires little local anaesthesia, minimal incisions, no flaps
elevations and no sutures. As a result, postoperative symptoms can be minimized.

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Correspondence to:Dr. Kazuyuki Kobayashi
Department of Periodontics and Endodontics, Tsurumi University, School of Dental Medicine
2-1-3, Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan
Fax: +81-45-573-9599 E-mail: kobayashi-kz@tsurumi-u.ac.jp
Accepted June 10, 2011.
Copyright ©2011 by the Asian Pacific Journal of Dentistry.
Online ISSN 2185-3487, Print ISSN 2185-3479

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