Endodontics

Endoscope- and video-assisted endodontic surgeryThomas von Arx, Dr Ueû DentVStefan Hunenbart, Dipl Ing /̂Daniel Buser, Prof Dr Med DenP

Since the introduction of microsurgical principles in Ihe 1990s, the field of endodontic surgery has madecontinuous and substantial progress. Particularly, root-end cavity preparation has been simplified andoptimized by means of newly developed surgical microinsfruments. However, the successful outcome ofendodontic surgery depends fo a large extent on accurate intraoperative diagnostics. Conventionally, mi-cromirrors (retromirrors) and microprobes have been used for this purpose. Recently, the surgical micro-scope has been used to enhance visibility during dental procedures. In addition, endoscopy has been re-ported to provide fhe surgeon wifh outstanding vision and ease of use. This arficle describes the technicalspécifications and the diagnostic application of fhe endoscope during endodonfic surgery, (QuintessenceInt 2002:33:255-259)

Key words: endodontic surgery, endoscopy, intraoperative diagnostics, video-assisted surgery

In medicine, endoscopie visualization for diagnosisand surgical therapy has become a standard of care.

Since the introduction of modern endoscopy byHopkins in the 1960s, various diagnostic and surgicalendoscopie techniques have continuously been refined,including arthroscopy, laparoscopy, and endoscopy inotolarnygology, gynecology, urology, and so on. In den-tistry, however, endoscopie techniques have not be-come popular yet. Only a few articles have describedthe intraoral application of endoscopy in dentistry,mainly in conventional or surgical endodontics,'"'Other dental applications of endoscopy have only beenmentioned occasionally,^-"

Following the introduction of microsurgical princi-ples in endodontic surgery, involving new preparationtechniques for root-end cavities,' there has been a con-tinuous search for enhanced visualization of the surgi-cal field. The authors have been using tbe endoscopein endodontic surgery for 2 years. In addition, the en-doscopie system has been constantly expanded to meetthe demands of the surgical team. The endoscope is

'Assistant Professor, Department of Oral Surgery and Stomatology, School

of Denfal Medicine, University of Bern, Bern, Switzerland.

^Scientific Collaborator, Department of Oral Surgery and Stomatology,

School of Dental Medicine, University of Bern, Bern, Switzerland.

'Professor and Chairman, Departmenf of Cral Surgery and Stomatology,

School of Dental Medicine, University ol Bern, Bern, Switzerland.

Reprint requests: Dr Thomas von Arx, Department cf Oral Surgery and

Stomatology, Sciiool of Denfal Medicine, tjniversity of Bern, Freiburg-

strasse 7, CH-3CtO Bern, Switzer land, E-mail: t i lomas.vonarx©

mainly applied for the following procedures: periradic-ular surgery {root-end resection), surgical perforationrepair, root resection, and root fracture evaluation.

The present article describes the endoscope andvideo system used by the authors as well as its clinicalapplication in endodontic surgery.

TECHNICAL DESCRIPTION

Ail components of the endoscope and video systemare placed on a multimedia cart (Fig 1), This cart isfully mancuverable from room to room and can be po-sitioned independently in the surgical room for opti-mal viewing.

The endoscopie camera and the camera controlunit (Endovision Telecam SL, Karl Storz) are the maincomponents of the system. Focusing and zooming(image size) can be directly operated by the surgeonwith two different rings located in front of the camerahead. The camera head has an integrated instrumentcoupler, to which the endoscope's ocular is inserted(Fig 2), The endoscope (rod-lens system) is a 6-cm-long and 3-mm-wide telescope with a viewing angle of70 degrees (Tele Otoscope with Hopkins 70° optics,Karl Storz) (Fig 3), This permits the surgeon to accessdifficult surgical sites.

The light cable from the cold light source (XenonNova, Karl Storz) is twisted onto the eonnector locatedat the bottom of the endoscope (Fig 4), Brightness canbe regulated via a mechanically operated dimmer onthe fountain unit. With a color temperature of 5600 K,

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Fig 1 Setup in tfie surgicai icon; .vi; d t media cart positioned Fig 2 Coupler ot camera tiead (lelt) and ocuiar ot endoscopeOpposite the surgeon, (right).

Fig 3 Endoscope with 70-degree viewing angie. At tiie bottom ofthe endoscope is the connector tor the iigint cabie.

Fig 4 Camera and iight cabie connected to \he endosoope.

Fig 5 Pen grasp for correct hold of the endoscope.

connector of tbe camera control unit with an S video-cahle. This permits capture of the video signals on dig-ital standard-sized or mini-sized cassettes (DVCAMcassette, Sony), A foot switch hooked up to the video-recorder allows the surgeon to control recording andpause modes, Sound recording is also possihle hy con-necting a microphone to the audio connector of theVideorecorder,

The videomonitor (Sony) is connected either to theS video output connector of the Videorecorder or di-rectly to the camera controi unit. The ongoing surgicalprocedure can he observed in real time, or capturedvideo signals can he played back.

the xenon lamp corresponds to the color temperatureof sunlight and therefore produces exceptionally hril-liant illumination. From time to time, a white halancemust he performed to reset the camera system'schrominance control to conform with the color tem-perature of the light source in use.

For medicolegal documentation or research pro-jects, a digitai Videorecorder {DVCAM digital medicalrecorder, Sony) can be connected to the video output

SETUP IN THE SURGICAL ROOM

In endoscopy, use of a monitor instead of viewingthrough the ocular is highly recommended. This allowsthe surgeon as well as the whole surgical team to viewthe surgery on the monitor. Teaching and instructingstudents and personnel is as simple as possible. In ad-dition, the surgeon maintains a correct posture whenworking from the monitor. The monitor should he

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TABLE 1 Applications of endoscopy in periradicular surgery

After osteotomy andlocation of root-end

•Morphology of apex•Presence ofe>rtraneous material

•Presence of perforation•Presence of rootfracture

After root-endresection

•Morphology of cutroot face

•Number andconfiguration cfroot canals

•Presence otisthmus tissue

•Presence of rootfracture

Root endpreparation

•Dimension ofcavity

•Direction anddepth of cavity

•Cleanliness otcavity walls

•Integrity of cavitymargin (cracks:chipping)

Root-endfilling

•Marginal adaptationof filing

•Presence ofdeficiencies

•Presence ofdisplaced material

placed opposite the surgeon at the level of the patient'slower leg region.

For aseptic reasons, the videocamera and the cam-era cable are packed in sterile covers and are subse-quently connected to the ocular of the endoscope.Both the light cable and the endoscope can be steril-ized (autoclavable up to 134°C), The surgeon holdsthe endoscope and camera in one hand with a pengrasp (Fig 5), In this way, the operator can readily ad-just the viewing angle and the position of the tele-scope lens. Surgery is more efficient when the sur-geon, not an assistant, guides the endoscope.

Good hemorrhage control is essential for obtaininghigh-quality pictures from the surgical field. In addi-tion, the endoscope lens must be cleansed regularlywith an antifogging solution. Direct contact with ro-tating or vibrating instruments must be avoided, be-cause these may damage the lens.

CLINICAL APPLICATIONS

The endoscope aids in several aspects of periradicularsurgery (Table 1). Following flap reflection and fenestra-tion of the buccal cortical plate, the endoscope is placednear the surgicai site for inspection of the root apex andany denuded root surface. At this stage, the presence ofirregularities such as lateral or furcational canals, perfo-rations, and extraneous materiai should be assessedwith the endoscope. In addition, roct or crown-rootfractures must be ruled out, because such findings di-rectly affect the progress of tbe surgery (Fig 6),

After root-end resection, the cut root face as well asthe removed apical fragment should be inspected withthe endoscope. Vital tissue staining with méthylèneblue dye is recommended for periradicular diagnosticsand tissue differentiation,'« The dye (concentration2%) is applied for 5 to 10 seconds to the surgical sitewith a smail gauze pad. The dye is then rinsed awaywitb saline. Méthylène blue stains not only organic tis-

sue components but also noninstmniented or nonob-turated root canais at the cut root face. This allows thesurgeon to observe the number and morphology ofcanal openings as well as any isthmus tissue that maybe present (Figs 7 to 9), In addition, staining withméthylène blue permits the detection of oblique or ver-tical root fractures. Staining the outline of the perio-dontal ligament allows verification that tbe root hasbeen resected entirely with respect to its cross section.

During root-end cavity preparation, the endoscopeaids in assessment of the extension, direction, anddepth of the retrocavity (Fig 10), Ideally, the prepara-tion should follow the original path of the root canal,but it should also include any isthmus tissue or lateralperforations. Following preparation, the cavity wallsare inspected for remaining gutta-percha or sealer, andthe cavity margins are examined for cracks and chip-ping. These should be eliminated by smoothing beforeplacement of the root-end filling. This permits bettermarginal adaptation of the restoration, providing atighter retrograde seal.

Following root-end obturation, the filling should beinspected for any deficiencies [Fig 11), Before woundclosure, the endoscope is used to examine the bonycrypt and to verify that no extraneous material is leftbehind.

DISCUSSION

The demand for use of optical aids for diagnosis ortherapeutic visualizadon wilt grow in the near futurein dentistry. The increasing number of publications onthe use of the surgical microscope in dentistry, "-' ' themarketing of such equipment, and the offering of con-tinuing education courses indicates the expanding in-terest of the dental community in this new technobgy.Therefore, the expanded use of tbe endoscope comple-ments the gaining popularity of applying magnificationtechniques in dentistry

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Fig 6 Root tace ot a mesial root oí a mandibular first molar fol-lowing root-end resection. A fine fissure runs from the buccal as-pect to the obturated buccal canal {armw), and then passesalong the isthmus to Ihe lingual canal (arrowheads).

Fig 7 Cut roof face of a maxillary second premolar showing twocanals connected by a small line ot isthmus (arrow). Ttie buccalcanal (top) is inadequately obturated. The méthylène blue dyehas also stained the cut periodontal ligament (arrowheads)

Fig 8 Mesial root of a mandibular first molar after root-end resec-tion. Ttie buccal and lingual canals are obturated with gutta-per-cha, but the isthmus has not been instrumented and obturated.

Fig 9 Distal roof of a mandibular tirst molar after root-end resec-tion. The isthmus tissue (arrow) is stained.

Fig 10 Rool end following refrograde cavify preparation with dia-mond-coaled and sonio-dnven retrofips.

Fig 11 Root end after retrograde obturation with mineral frioxideaggregate.

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The advantages of endoscopy compared to surgicalmicroscopy have been described as follows '̂':

1. Endoscopy is a readily transportable, versatile, andexpandable system.

2. It provides excellent illumination and tiiagnifica-tion.

3. Adjustment of tbe viewing angle is rapid and easy.4. It allows direct viewing; no mirrors are required.5. Angled optics peniiit the surgeon to "look around

the corner."6. Its depth of field and focus are similar to the ability

of the human eye to make visual adjustments.7. Tbe endoscope and light cable can he sterilized.8. The learning curve is short.9. Because of its small size, the technology is not in-

timidating to patients.

A shortcoming of the endoscope is the repeated ne-cessity of cleaning the lens because of fogging or soil-ing witb blood, tissue, or coohng agent.

Tbe autbors believe tbat endoscopy will further im-prove the outcome in endodontic surgery. The adventof microsurgical principles have clearly optimized theresults in endodontic surgery,'*""-' and the best possi-ble intraoperative visualization is necessary to main-tain a bigh level of success. In addition, endoscopysbould be instituted in otber fields in dentistry. Furtberindicafions may include tbe removai of inadvertentlydisplaced or fractured teeth and roots, tbe removal ofextraneous material, and the performance of sinusfloor elevafion

ACKNOWLEDGMENTS

The authors thank J. Anklin AG, Binnjngen, SwUzerland, for techni-cal support and for lending the endosrape and video equipment. TheSwiss Dentai Assodation (SSO¡ is acknowledged for a research grant{SSO foundation for dental rescarc:h project No. 20Ü1 on endoücope-and video-as5Í5ted endodontif surgery.

REFERENCES

1. Detsch SG, Cunningham WT, Lotiglors ]M. Endoscopy asan aid fo endodonlic diagnosis. ] Endod 1979;5:60-62.

2. Marshall GW, Lipsey MR. Heuer MA, Kot C, Smarz R,Epstein M. An endodontic fiber endoscope for viewitig in-strumented root canals. | Endod 1981;7:85-88.

3 Held SA, Kao YH, Wells DW. Endoscope-An endodonticapplication. J Endod 1996;22:327-529.

4. Bahcall ]K, DiFiore PM, Poulakidas TK. Ati endoscopietechnique for endodontic surgery. ] Endod 1999;25:132-135.

5. Beery QC, Aramany MA, Katzenbei^ B. Oral endoscopy inprosthodontic management of the soft palate defect, JProsthet Dent 1985 ;54:241-244.

6. L'Estrangc PR, Bevenius J, Williams L. Intraorai applicationof microcolpohysteroscopy. A new technique for clinical ex-amination of oral tissues at high magnification. Oral SurgOral Med Oral Pathoi 1989;67:282-285.

7 L'Estrange PR, Karlsson SL, Odman P, Stegersjo G,Engstrom B. Clinical evaluation of restoration margins byan endoscopie microscope. Aust Dent ] 1991;36:415-420.

8. Ozawa T, Tsuchida M, Yamazaki Y, Arai T, Nakamura J.Clinical applicatioti of a fiberscope for periodotital lesions:Case reports. Quintessence Int 1999;30:615-522.

9. von Arx T, Walker W, Microsurgical instruments for root-end cavity preparation following apicoectomy. Endod DentTraumatol 2000; 16:47-62.

10. Cambruzzi |V, Marshall FJ, Pappin JB. Méthylène blue dye.An aid to endodontic surgery. J Endod 19Ö5;11:311-314.

11. Carr GB. Advanced techniques and visual enhancement forendodcintic surgery. Endo Report 1992;7(l):6-9.

12. Carr GB. Microscopes in endodontics. J Calif Dent Assoc1992:20:55-61.

13. Pécora G, Andreana S. Use of dental operating microscopein endodontic surgery. Oral Surg Oral Med Oral Pathol1993:75:751-758.

14. Kim S. Principles of endodontic microsurgery. Dent ClinNorth Am 1997;41:481-497.

15. Velvart P. Das Operationsmikroskop. Neue Dimensionen inder Endodontie. Schweiz Monatsschr Zahnmed 1996;106:357-364.

16. Velvart P. Das Operationsmikroskop in der Wurzel-spitzenresektion. 1. Die Resektion. Schweiz MonatsschrZahnmed 1997;107:507-516.

17 Velvart P. Das Operationsmikroskop in der Wurzelspitzen-resektion. 2. Die retrograde Versorgung. SchweizMonatsschr Zahnmed 1997 ¡107:969-978.

18. Rubinstein RA, lüm S. Short-term observation of the resultsof endodontic surgery with the use of a surgical operationmicroscope and Super-EBA as root-end filling material. JEndod 1999;25:43-48.

19. Perrin P, Jaeky D, Hotz P. Das Operationsmikroskop in derzahnärztlichen Allgemeinpraxis. Schweiz MonatsschrZahnmed 2000:110:547-954.

20. von Arx T, Kurt B. Root-end eavity preparation after api-coectomy using a new type of sonie and diamond-surfacedretrotip: A 1-year follow-up study. | Oral Maxillofac Surg1999;57:656-661.

21. von Arx T, Gerber C, Hardt N. Periradicular surgery of mo-lars: A prospective clinical study with a 1-year follow-up,int Endod J2001;34:520-525.

22. Engeike W, Deckwer I. Endoscopically controlled sinusfloor augmentation. A preliminary report. Ciin Oralimplants Res 1997;8:527-531.

23. Baumann A, Ewers R. Minimal invasiver Sinuslift, Grenzenund Möglichkeiten im atrophen Oberkiefer. Mund iiieferGeslchtschirl999;3(suppl] S70-S73.

24. Wiltfang J, Schultze-Mosgau S, Merten HA, iiessler P,Ludwig A, Engelke W. Endoscopie and ultrasonographicevaluation of the maxillary sinus after combined sinus flooraugmentation and implant insertion. Oral Surg Oral MedOral Pathoi Oral Radiol Endod 2000;89:288-291.

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