Periodontics

Clinical application of a fiberscope for periodontal lesions:Case reports

Toshiko Ozawa, DMD. PhDVMamiTsuchida, DMD, PhD"/YasushiYamazaki, DMD. PhD"/Takeshi Arai, DDS, PhD"'/Jiro Nakamura, DDS, PhD"**

In dentistry the endoscope has generally been used to visualize inaccessibie areas, eg. inside root canaisor coronal surfaces of teeth; however, it has not been used in periodcntaily diseased lesions. In this study,a newly designed fine fiberscope (0.8- to hO-mm outer diameter) with an irrigation system was used tovisuaiize root surfaces and periodontai tissues affected by penodontai disease. The fiberscope was in-serted through fistulas, periodonta! pockets, or roct furcations in 5 patients to provide clear operationaiviews without the obstruction of blood or soft tissues. The irrigation system of the endoscope effectively al-iowed differentiation of hard and soft tissues as well as restorative materiais. The fiberscope system devei-oped in this study was effective for diagnosis, for enhancing visuaiization for periodontai surgery, and fortreating lesions such as fistulous tracts or furcation iesions. (Quintes3ence int 1999:30:615-622)

Key words: liberscope, tiberscopic findings, fistula, periodontai lesions, pericdontai pocket, root furcation

Currently available conventional diagnostic proce-dures {for example, general clinical and radio-

graphic examinations) fail to consistently provide cer-tain diagnostic information. For example, diagnosis ofperiodontal lesions through conventional methods isdifficult. As a result, many lesions can only be con-firmed after surgical exploration. The ability to observethe periodontal tissues and the root surfaces involvedin periodontal disease wouid be useful for diagnosisand treatment.

The endoscope is widely used in medicine as aneffective means of diagnosing and treating inaccessiblelesions,'-^ In dentistry, however, the endoscope hasmainly been used to observe the inside of root canalsor the coronal surface of teeth^"' and has rarely beenapphed to lesions affected by periodontal disease.^ Tovisualize the inaccessible area involved in periodontaldisease, we have developed a fine fiberscope for endo-scopie use. This fiberscope has been used in our chnicto diagnose and treat periodontal iesions.

'Lecturer, Department of Periodontics and Endodontics, TsurumrUniuersity, Sciiooi of Dentai Medicine, Yoiiofiama, Japan.

'• inslructor. Department of Periodontics and Endodontics, TsurumiUniversity, School of Dental fuledictne, yoi<oharna, Japan.

"'Professor of Dentistry, Department of Periodontios and Endodontics,Tsjiumi University, Schooi of Dental fuledicme, Yokohama, Japan.

•"•Professor of Dentistry and Chairman, Department of Periodontios andEndodontics, Tsurjmi Uniuersity, Scfiooi ot Dental Medicine, Yoko-fiama, Japan

Reprint requests: Dr Tosfiiko Ozawa, Lecturer, Department of Peii-odontics and Endodontics, Tsurumi University, School of Dental Medicine,2-1-3, Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan Pax: 81-45-583-6401.

This article will describe the newly designed finefiberscope. Six representative cases in 5 patients willbe discussed to show its efficacy when clinicallyapplied to observe the root surfaces and the periodon-tal tissues involved in periodontal disease.

FIBERSCOPE DESIGN AND SYSTEM

The fiberscope consists of image fibers (3,000 pixels;vision field; 65 degrees; field depth; 0,8 to 15.0 mm)together with hght guides and a channel with an innerdiameter of 0.3 mm for irrigation with distilled water,which is supplied through an attached syringe (Figs 1and 2).

Three types of needles were designed (Table 1), Thefirst type (A) has an outer diameter of 0,8 mm and isbent at an angle of approximately 135 degrees, 16 mmfrom the tip, similar to a periodontal probe. Clinicalapplication of this needle design indicated that theneedle needed to be strengthened. Consequently, asecond needle type (B). with an outer diameter of 1,0mtn and a gradual curvature, was designed. Design Cis a shorter needle with a more acute curve.

The magnification of the fiberscopic image isdependent on the distance from the object to thefiberscopic tip. Magnification of approximately x30on a 9-inch monitor is reached 1 mm from the object;at 2 mm, the magnification is smaller. The remainingendoscopie system consists of an imaging unit(Medical Science), a color video monitor, and a videorecorder to capture the monitor image in real time(Fig 3).

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image guides (3,000 p ixe is)

Light guides

irrigation channe

TABLE 1 Characteristics of the fiberscope

TypeForm olneeeiie

Outerdiameter Location ot insertion

A Siiarp angie 0.8 mm FistuiaPerioe:lcnlai pocket, rootcanai

6 Graduai curve 1.0 mm PisluiaPetiodontai pocket, rootcanai

C Acute curve 1.0 mm Root furcation, tistuia

Pig 1 (left) Cross-section of the needie. Ttie tiberscope consistsoí image fibers (3,000 pixeis) together with iight guides ane:! achannel (inner diameter: 0.3 mm) for water irrigation, which is sup-piied througfi an attached syringe.

Fig 2 Fiberscope with syringe attached loiwater irrigation.

Fig 3 (right) Endoscopie systern. coiorvieJeo monitor (top) and imaging unit (bot-ton-i). The endoscopie syslem consists of animaging unit, a eoior video monitor, and avideo recorder to capture the monitor imagein reai time.

TABLE 2

Case

123

456

Summary of fibers copie examinations

Sex

FFF

FFM

Age

27 y27 y54 y

47 y53 y46 y

Tooth

11 (8)12 (7)14 (5)

14 (5)15 (4)46 (30)

Location ol insertion

FistuiaFistuiaPistuiaPeriodontai pocl<etFistuiaPeriodontai pocl<etRoot furcationPeriodontai pocl<et

Main Undings

Root résorptionAmaigam retroseaiingPerloration

Reot fractureRoot fractureFurcation perforationEnamei projection

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Fig 4a Cases i and 2. Preoperative view of2 fistulas (arrows) of the maxillary right centralincisor (case 1 ) and lateral incisor (case 2).

Fig 4b (right) Cases 1 and 2. Preoperativeradiograph of the maxillary ngfit central in-cisor (case 1] showing post. core, andcrown with incomplete root canai obturationand a periapicai radiolucency, and the lat-erai incisor (case 2) showing an amalgamseai on the middle third ot the root at the topot the post and a radioiucency along theconcave distai root surface.

w —j Root V

/ " ^ ^ ^ Soft tissue ^

< ^ . . , f

^ ^ ^ ^ Sofl tissue

KL)J~~J^~ f̂ oot résorption_ : : ' ^ Roof

^ ^ ^ ^ Soft tissue

•^^^/^—- Root resorpfionij^ Root

Figs 4c and 4d Case 1. Fiberscopic findings (fiberscope inserted in fistula). Dark shadows arepresent on the distal rool surface (top) and around the rool apex (bottom).

CLINICAL APPLICATION ANDRBERSCOPIC OBSERVATION

Cases considered appropriate for clinical applicationof tbe fiberscope were patients who presented withfistulas, periodontal pockets, or root furcation withbone defects through which the needle could beinserted. The root surfaces and periodontal tissuesinvolved in periodontal disease were observed underlocal anesthetic. During observation, the areas wererinsed with sterilized distilled water. Six clinicalcases involving 5 patients will be presented asexamples of diagnosis with the fiberscopic system(Table 2).

CASE REPORTS

Case 1: Root résorption

Ten years after root eanal treatment and placement ofa crown on a maxillary right central incisor, a fistulathat was traced to the root apex developed (Fig 4a). Aradiograph revealed the post, core, and the crownwith incomplete root canal obturation and periapicairadiolucency (Fig 4b).

Tbc fiberscope was inserted tbrough the fistula. Thefiberscopic observafion revealed dark shadows on thedistal root surface and around the root apex, suggest-ing root résorption that was not ohserved radiographi-cally (Figs 4c and 4d).

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Amalgam Amaigam

-Root

Dead space

Figs 5a and 5b Case 2, Fiberscopic findings {fibersccpe inserted in fislula). The condition of theamalgam seai is yisibie on the distai root surface. The shining portion is believed to be the amaigam.and the dark portions between the amalgam and the tooth structure are considered to be dead space.

Fig 6a Case 3, Preoperative view i.l ,i . • i i j .. ihemaxillary right lirst premolar with a 6-'niri bLjccdi peri-odontal pocket.

Fig 6b (right) Case 3. Preopeiative radiograph of themaxillary right first premolar, shewing a radiolucencyon the mesial aspect of the middle third of the buccalroot, in which widened post restoration had been per-lormed. The periodontal ligament space is wider¡thicker) around the root apex.

Case 2: Amalgam retroseal

Ten years prior to fiherscopic examination, in tbesame patient in ease 1, a maxillary right lateral in-cisor was prepared as a natural abutment for place-ment of a crown, A radiolucency developed, resultingfrom perforation during the post placement, Endo-dontie surgery was performed as a secondarytreatment. After removal of tbe granulation, an amal-gam retroseal was placed on the distal root surface.Three years after this operation, a fistula that wastraced to the distal root surface developed (see Fig4a). A radiograph revealed tbe amaigam sea! on themiddle third of the root at the top of tbe post and aradiolucency along the concave distal root surface(see Fig4h).

Tbe fiberscope was inserted through the fistula. Thecondition of the amalgam seal was observed on thedistal root surface. The amalgam alloy was visible as a

sbiny surface, and tbe cavosurface interface betweenthe amalgam alloy and the tootb structure was visibleas a dark gap or a dead space (Figs 5a and 5h),

Case 3: Post perforation

The patient reported that swelling had been presentfor 2 montbs before she came to the dentist. The max-illary right first premolar presented with a fistula. Anabscess was observed, and a buccai periodontalpocket was probed to a depth of 6 mm, resulting inbemorrbage and exúdate (Fig 6a), A radiograph re-vealed a radiolucency on the mesial aspect of tbe mid-dle third of tbe huecal root, in wbich a widened postrestoration had been previously placed. The periodon-tal ligament space was observed to he wider (thicker)around the root apex (Fig 6b).

The fiberscope was inserted through the fistula andthe periodontal pocket. Prior to the fiberscopic proce-

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Mêlai post

Figs 6c and 6d Case 3. Fiberscopic tindings (tiberscope inserted in fistula ¡iettj and periodontal pocket IriahtHAn indigocarmine dye was injected into the tistula and periodontsi pocket prior to observation As the fiberscopewas inserted through the tistula, it reached a iarge bony delect. A iarge perforation defect is visibie en themesiobuccal root surtace, on which an area ot the metal post and soft tissues can be seen (ieH) The same view JSvisible through the periodontal pocket delect (rigi^t)

Fig 7a Case 4 Preoperaiive view of a tistula of ttiemaxiilary right first premolar.

Fig 7b Case 4. Preoperative radiograph cfthe maxiiiary righl first premclai, shewing athickened periodcntal ligament spacearound the root apex and a post restorationthat had been placed toward the middle ofthe root canal.

Soft tissue

Root tracture

Figs 7c and 7d Case 4. Fiberscopic findings (tiberscope inserted in fistula) A root fracture is visi-ble on the buccai root surface toward the root apex.

dure, an indigocarmine dye was injected into the fis-tula and periodontal pocket. As the tiberscope was in-serted through the fistula, it reached a large bony de-fect. A large perforation defect was observed on themesiobuccal root surface, on which an area of themetal post and the soft tissues were visible (Figs 6cand 6d), The same view was seen through the peri-odontal pocket defect. Both of these views confirmedthat the fistula could be traced to the periodontalpockets, a result of the post perforation.

Case 4: Root fracture

Two years after root canal treatment and placementof a final prosthesis, a fistula had developed on the buc-cai gingiva, 3 weeks prior to examination ¡Fig 7a). Aradiograph revealed a thickened periodontal ligamentspace around the root apex. A post restoration had beenplaced toward the middle oí the root canal {Fig 7b).

The fiberscope was inserted through the fistula. Aroot fracture was observed on the buceai root suriacetoward the root apex (Figs 7c and 7d).

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Fig Ba Case 5. Preoperative view of a 7-mm prob-ing periodonlal pocket on the distopaiatal aspect anda periodonlal probe througii tiie gingivai suicus of themaxiiiary rigiit second mola: (mirror view).

Fig 8t) Case 5. Preoperative ra-diograph of the maxiiiary rigfitsecond premolar, showing aIhickened periodontal iigamentspace around the root

• \ ^ Soft tissue

X. .y fracture V _V-J-Rooly/ fracture

Figs 8c and 8d Case 5. Fiberscopic findings (iiberscope inserted in periodontal pocket]. A verticairoot tracture, as weli as granulation tissue, is visibie on the root surface in the pocket.

Fig 8e Case 5. Extracted looth. Theroot fracture on the distopaiatai root sur-face corroborated the fiberscopic obser-vation.

Case 5: Root fracture

The patient complained of discomfort during bitingand chewing. Although curettage had been performedpreviously, a 7-miTi pocket remained on the disto-palatal aspect of the maxillary right second premolar(Fig Sa). A radiograph revealed a thickened periodon-tal ligament space around the root (Fig 8b).

The fiberscope was inserted through the periodon-tal pocket, revealing the presence of granulation tissueas well as a vertical root fracture (Figs 8c and 8d),One month after fiberscopic observation, both thecrown and the post on which it was placed were dis-lodged. Because the prognosis for the tooth was poor,the tooth was extracted. The clearly visible verticalroot fracture confirmed the fiberscopic observation,showing the importance of this technology (Fig 8e}.

Case 6: Furcation perforationand enamei projection

Eight years after post-and-core and crown restorationof a mandibular right first molar, fiberscopic examina-tion was performed for diagnostic means. The patienthad noticed gingival recession 6 months prior to

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Fig 9a Case 6 Preoperative view of gingi-val recession and the exposed root fureationat tiie mandibuiar first moiar.

Pig 9b Case 6. Preoperative radiograph ottfie mandibuiar right first moiar, showing thefurcation and a periapicai iesion arcund thedistai and mesiai root apices. A fragment ol afractured instrument is present at the apicaithird of the distai root canai. A widened postrestoration is visibie at the coronai third in themesiai root canai. Bone rarefaction suggestspost perforation tiirough the furcai area

Pigs 9c and 9d Case 6. Fjberscopic findings (fiberscope inserted in root turcation ane:t periodontaipoeKet) An enamei pro|eetion extends deepiy into the furcation (ieft). A perforation on the distai sur-face of ttie mesiai root in the furoation is visible as a blue stain (center). Some white attachments,simiiar to eaicuius, are present on the apicai portion of root surface (right).

examination. The root surface of the furcation wasexposed, and probing of the furcation reached a depthof 6 to 8 mm (Fig 9a). A radiograph revealed the fur-cation and periapical lesion around the distal andmesial root apices. A fragment of a fractured instru-ment was discovered at the apical third in the distalroot canal. A widened post restoration was visibie atthe coronal third of the mesial root canal. Bone rare-faction suggests that post perforation had occurredthrough the furcai area (Fig 9b).

Before fiberseopic observation, an indigocarminedye was injected to differentiate tissue types. The fiber-scope was inserted through the root furcation and theperiodontal pocket, which showed an enamel projec-tion extending deeply into the furcation [Figs 9c and9d). A perforation of the distal surface oí the mesialroot in the furcation was observed as a blue stain.

Some additional white attachments, simiiar to calcu-lus, were seen on the apical portion of root surfaces.These attachments were removed with a curettage.

DISCUSSION

To allow visualization of the fields involved in peri-odontal disease, a fiberscope with an irrigation chan-nel and curved needle was designed for endoscopieuse and was applied ciinically. When the fiberscopewas inserted through a fistula, the extent of bone losswas visible, and the soft tissues and root surfaces in-volved in the periodontal lesions could be diïïerenti-ated. The location of perforations caused by metalposts and the cavosurface margin adaptation of amal-gam alloys on the root surfaces were particularly clear.

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When the fiberscope was inserted tbrougb a periodon-tal pocket, excellent visuaiizafion of fractures and per-forations located on root surfaces was obtained.Perhaps of greater surgical importance is the abifity toobserve periodontai tissues and root surfaces beforesurgical intervention, overcoming certain diagnosticdifficulties typically encountered in lesions witboutdirect access or reliable radiographie definition. Themodified fiberscope system demonstrated its effective-ness not only for tbe endoscopie diagnosis of peri-odontal disease but also for confirmation of complica-fions resulting from restorative treatment

Rinsing witb sterilized distilled water was essential toobtaining a clear view without biood or detached softtissue obstruction and to differentiating between softand bard tissues, because small soft tissues move duringthe flushing process. Injection of dye provided cn-banccd visualization to distinguish between both hardand soft tissues as well as restorative materials. The useof dye staining is quite common for fiberscopic observa-tion in medicine. In addition, méthylène blue dye hasbeen reported as a useful aid in endodontic stirgerj'.' IIremains to be deterrnined wbat is the most appropriatedye and to determine its effects oti fiberscopic observa-tion of periodontal tissues and root surfaces.

Because the needle of the fiberscope is fine andcurved, it can be inserted in various locations. Aftboughtbe fiber is placed in a rigid tube of stainless steel, its di-ameter is small; therefore, the fiber may bend if unnec-essary pressure is exerted against the hard tissues(tooth and bone). In tbis manner, tbe bond betweentbe lens and the image fiber may fail. The fiber andsome parts of this instrument are not heat stable andmay fail when subjected to high temperatures.Therefore, the instrument should only be sterilized bychemical agents such as glutaraldehydc or cthyleneoxide gas.

With this endoscopie system, the image on thevideo monitor is a clear enlargement. Consequently,several observers can view tbe procedure in real timealong witb the operator. In addition, the recordedimage can be used for explanation to patients, as wellas for a discussion of diagnosis with, and education of,students and colleagues.

This fiberscopic system is useful not only for diag-nosis but also for operative procedures. The fiberscopecan work with other instruments when sufficientspace exists in the lesion area. However, care must betaken not to damage the thin fiberscope with theseinstruments, a difficult task. To overcome this diffi-culty, the fiberscope was designed with a workingchannel that allows introduction of instruments suchas a fine laser fiber and an endodontic file. For severalclinical cases, the fiberscope has already been testedwitb a working channel in which a Nd:YAG laser wasinserted for treatment. Good operational views wereobtained during tbe laser irradiation. In the future, wewish to improve the fiberscope and to apply it to newtreatment methods using an additional working chan-nel (tube) and modified instrumentation.

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