1 7 6 Dental Update – May 2001

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Abstract: Iatrogenic root perforation is a procedural error that complicatestreatment and can lead to loss of the tooth. A number of new instruments andtechniques have been introduced into endodontic practice over the last few years toaddress this problem. The recent addition of the operating microscope to improve thefield of vision has provided the operator with the benefit of magnification andenhanced illumination. Although there are few studies evaluating objectively the useof the operating microscope, its clinical application demonstrates the possibility ofachieving more precise endodontic practice. The use of the operating microscope inthe non-surgical management of a mid-root perforation is reported in this paper.

Dent Update 2001; 28: 176-180

Clinical Relevance: This paper describes a clinical technique to manage mid rootperforation. The impact of using the operating microscope is discussed.

E N D O D O N T I C S

ver the last few years, the use of magnification has been gaining

popularity in dental practice. Variousinstruments have been used, rangingfrom simple loupes to the moresophisticated operating microscope(OM). In a questionnaire conducted byMines et al.,1 reported usage of the OMin practice was increased, especiallyamong newly qualified endodontists.The survey showed that the OM wasused most in managing proceduralerrors and surgical endodontics.

In addition to the incorporation ofcoaxial illumination, the OM provides awide range of magnification, from x1.7up to x35. The simple premise for usingthe OM is that efficient use of light

plus magnification can result in moreprecise dentistry.

The OM has many applications inthe field of endodontics. In addition toa number of clinical applications, it canbe used for documentation, patienteducation and marketing, and hasrevolutionized the practice ofendodontics by allowing the adoptionof new techniques and instruments.

Root perforation is a proceduralerror that can have a profound effecton the prognosis of treatment. It hasbeen reported that perforations are acommon cause of endodontic failure.2

Surgical repair or extraction has beenthe conventional treatment for rootperforation. It has also been claimedthat non-surgical treatment ofperforation is limited because of thedifficulty in determining theperforation�s location, shape and sizein addition to the lack of a matrixagainst which the sealing material canbe packed without excess spreadinginto the periradicular tissues.3 The

introduction of the OM into practicehas provided dentists with the abilityto explore the root canal anatomy ingreater detail. This has made itpossible to attempt a moreconservative approach to perforationrepair.

In the following case, the OM wasused in the non-surgical repair of aniatrogenic root perforation usingcalcium hydroxide as an interimdressing and gutta-percha as a sealingmaterial.

CASE HISTORYA 59-year-old woman was referred tothe conservation department at theEastman Dental Hospital with aniatrogenic root perforation in 2|. Thetooth served as a bridge abutment thatextended from 2 | 3 and requiredreplacement because of poor aestheticsand secondary caries (Figure 1). Theperforation had occurred during theprocess of removing the post-retainedbridge (Richmond type) and regainingaccess to the root canal system.

At the time perforation occurred, thepatient reported feeling a sudden sharp

Microscopic Management ofEndodontic Procedural Errors:

Perforation RepairM. FIRAS DAOUDI

O

Figure 1. The clinical appearance of the oldbridge.

M. Firas Daoudi, DDS, LDS RCS (Eng.), MSc(Lond.), Research Fellow, ConservationDepartment, Eastman Dental Institute for OralHealth Sciences (UCL), University of London, andSenior House Officer, Unit of ComprehensiveRestorative Care, Dundee Dental School andHospital.

E N D O D O N T I C S

Dental Update – May 2001 1 7 7

pain and the dentist noticed bleedinginto the previously dried canal. Animmediate radiograph confirmed thepresence of mid-root perforation(Figure 2), which was also confirmedwith an apex locator. The originalbridge was re-cemented temporarily andthe patient referred for furthertreatment.

ExaminationThe patient was symptom-free whenseen the day after the perforation. Afterremoval of the bridge, the tooth wasisolated using rubber dam. The rootcanal was irrigated using sterile water

and dried. The OM was used to locatethe perforation site and to assess indetail the degree of damage caused bythe perforation. Bleeding from theperforation site was controlled usingadrenaline (epinephrine)-impregnatedcotton pledgets (Racellet, Henry ScheinInc., NY, USA).

An endodontic explorer (DG-16 Hu-Friedy, Chicago, Il, USA) was used toassess carefully the perforation bordersinside the canal. The perforation was oflimited extent, located at the mid-rootlevel in the distobuccal wall of the root,was approximately 1.5 mm in diameterand oval in shape.

The efficient use of magnificationfacilitated the process of regainingaccess to the whole root canal system.Extra care was exercised to avoid anyfurther damage to the perforation site.A radiograph with a file in place wastaken to confirm access to the fulllength of the root canal (Figure 3).

TreatmentThe root canal system was preparedusing modified double flare techniquewith copious irrigation using 3%sodium hypochloride and sterile water.The canal was then dried and calciumhydroxide powder used to pack theperforation site and the canal as atemporary dressing. The canal accesswas sealed with IRM (L.D. Caulk Co.,Milford, DE, USA) and arrangementwas made to provide the patient with atemporary overdenture prosthesis toallow complete canal sealing, thuspreventing coronal microleakage fromthe ill-fitting bridge.

The calcium hydroxide dressing wasreplaced after 8 weeks. On thatoccasion, a clot-like plug at theperforation site was observed throughthe OM and special care was taken notto disturb this potentially healingtissue.

After another 8 weeks, during whichthe patient remained symptom-free, theroot canal was totally dry and it wasdecided to obturate the root canalsystem and to repair the perforationnon-surgically. The apical third of thecanal was obturated first using a warm

vertical condensation techniqueutilizing the Touch�n Heat instrument(Analytic Technology, model 5004, Kerr,UK). The perforation was then sealedwith softened gutta-percha using aperforation repair instrument (West,EIE, San Diego, CA, USA) to pack thematerial. A radiograph was taken toverify the quality of the repair and noexcess material was noted (Figure 4).The rest of the canal was fullyobturated with softened gutta-perchaand a final radiograph taken to assessthe quality of the filling (Figure 5).

Follow up TreatmentAfter monitoring for 3 months, the root

Figure 2. Mid-root perforation with a fileextending into the periradicular tissues.

Figure 3. Achieving full access to the rootcanal system.

Figure 4. Perforation repair with gutta-percha.

Figure 5. Final root canal filling.

1 7 8 Dental Update – May 2001

E N D O D O N T I C S

canal of the 2| was prepared to receive acast gold post and core. Once again theOM was used to make sure that theperforation site was not disturbed. Apost was cemented in place using zincphosphate cement (DeTrey, Dentsply,UK) and a temporary bridge fitted for aperiod of 6 months.

The tooth remained symptom-freeduring the follow up period, after whicha definitive bridge was fitted (Figure 6).Three years after the initial treatment,the radiographic evidence demonstratesa normal periodontal space around thetooth with no signs of pathology(Figure 7).

DISCUSSIONAlthough dentistry deals with delicatetissues, the dental profession is stillless well advanced than its medicalequivalent in respect of new methods ofvision enhancement, including the OM,on a widespread clinical level. However,the clinical use of the OM has beengaining increased popularity, especiallyamongst newly qualified endodontists.1

The introduction of the OM intoendodontics has greatly enhancedvisual access because of the increasedmagnification and coaxial illumination.Its use brings a number of advantages,but initially practitioners can encounterdifficulty in adapting to a newoperating position, which will increasethe treatment time.1 Absolute patientco-operation and the presence ofhighly trained dental assistants areinvaluable in overcoming the limitationto the dentist�s visual field.4

Adopting the use of the OM intoroutine practice should be consideredas an investment that requires training

and the development of technique andinstrumentation. Once mastered it ispossible for the operator to reach aphase of maximum productivity withmuch improved quality of work.

Although clinical experience and anumber of reports claim that using theOM provides better results,5 theliterature provides conflicting objectiveevidence regarding this matter.Improved surgical results have beenreported when adopting the newendodontic microsurgery principleusing the OM6 and the use of the OMwas claimed to provide better efficiencywhen locating root canals and theiristhmuses.7 Indeed, Stropko reportedan increase in identification andtreatment of the second mesial buccalcanal (MB2) in molar teeth with the useof OM.8 However, two studies haveshown no significant difference inlocating fourth canals in molars9 or in theeffectiveness of gutta-percha removalfrom root canal using the OM.10

Iatrogenic root perforationcomplicates treatment and compromisesthe prognosis if it is not managedproperly. There is a generally heldbelief that perforated teeth have a poorprognosis. The non-surgical approachhas several drawbacks: it can bedifficult to identify the site of theperforation, its shape and size and canmake adequate sealing of theperforation without excessiveoverfilling clinically challenging.3 Manyfactors contribute to the prognosis,including the time that the perforationhas been present, its location and itssize. The sooner the perforation istreated, the smaller and the further theperforation site is from the gingivalsulcus, the better the prognosis.11

These factors all minimize the chancesof contaminating the perforation sitewith bacteria.

The basic principles of perforationmanagement remain unchanged with theuse of the OM. Once a perforation hasoccurred, its site should be located. Thiscan be achieved by direct vision withthe OM or using a radiograph, an apexlocator, or paper points. The perforationarea should be thoroughly cleaned andimmediately repaired, or at least dressed

with calcium hydroxide, ensuring that nobacterial leakage takes place. Calciumhydroxide, in spite of the controversyregarding its mode of action, is still oneof the most widely used materials inperforation management. It helps promotehealing with its antibacterial propertiesand prevents the ingrowth of granulationtissue into the root canal.12

Different materials have been used forperforation repair with variable degrees ofsuccess, for instance:

! amalgam;! intermediate restorative material

(IRM);! glass polyalkenoate cement;! composite resin;! gutta-percha.

The use of biocompatible material (e.g.tricalcium phosphate or hydroxyapatite)as a matrix against which the repairmaterial can be condensed wassuggested to control extrusion of repairmaterial.13

Softened gutta-percha adapts well tothe perforation and has the advantagesof being relatively inert if inadvertentlyextruded into the periradicular tissue.14

More recently mineral trioxide aggregate(MTA) material has been introduced,with promising results. It has beenclaimed that MTA provides abiocompatible immediate seal to theperforation site with optimum healing.15

Figure 6. The newly fitted bridge.

Figure 7. The appearance 3 years afterroot canal filling and repair of theperforation: note the healthy tissues.

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CONCLUSIONThe use of newer materials andtechniques in endodontic practice allowsthe dentist to attempt a moreconservative approach to perforationrepair with promising results. The casepresented shows excellent healing after a3-year period of follow up using a non-surgical repair of an iatrogenic mid-rootperforation.

ACKNOWLEDGEMENT

The author would like to thank Dr K. Gulabivala for hisclinical advice and Professor W.P. Saunders and DrK. Elias for their advice in preparing this paper.

REFERENCES

1. Mines P, Loushine RJ, West LA, Liewehr FR,

Zadinsky JR. Use of the microscope inendodontics: A report based on questionnaire. JEndodont 1999; 25: 755–758.

2. Ingle JI. A standardised endodontic techniqueutilising newly designed instruments and fillingmaterials. Oral Surg Oral Med Oral Pathol 1961; 14:83–91.

3. Lantz B, Persson PA. Periodontal tissue reactionafter surgical treatment of root perforation indogs’ teeth. A histological study. Odontol Revy 1970;21: 51–62.

4. Saunders WP, Saunders EM. Conventionalendodontics and the operating microscope. DentClin North Am 1997; 41: 415–428.

5. Wong R, Cho F. Microscopic management ofprocedural errors. Dent Clin North Am 1997; 41:455–479.

6. Rubinstein RA, Kim S. Short term observation ofthe results of endodontic surgery with the use of asurgical operation microscope and super-EBA asroot-end filling material. J Endodont 1999; 25: 43–48.

7. Yang SF, Hsu JR, Pai SF, Tsai CL. In-vitro efficacy ofmicroscope and dye on identifying root canals inroot end resection. J Endodont 1999; 25: 293 (abstr.44).

8. Stropko JJ. Canal morphology of maxillary molars:Clinical observation of canal configuration. JEndodont 1999; 25: 446–450.

9. Sempria N, Hartwell G. Frequency of fourth canalsin maxillary molars located when using an operatingmicroscope: a clinical study. J Endodont 1999; 25: 307(abstr. 36).

10. Balassari-Cruz LA, Wilcox LR. Effectiveness ofgutta-percha removal with and without themicroscope. J Endodont 1999; 25: 627–628.

11. Fuss Z, Trope M. Root perforations: classificationand treatment choices based on prognosticfactors. Endodont Dent Traumatol 1996; 12: 255–264.

12. Foreman PC, Barnes IE. A review of calciumhydroxide. Int Endodont J 1990; 23: 283–297.

13. Alhadainy HA. Root perforations: A review ofthe literature. Oral Surg Oral Med Oral Pathol1994; 78: 368–374.

14. Schilder H. Filling root canals in threedimensions. Dent Clin North Am 1967; 11: 723–744.

15. Nakata TT, Bae KS, Baumgartner JC. Perforationrepair comparing mineral trioxide aggregate andamalgam using an anaerobic bacterial leakagemodel. J Endodont 1998; 24: 184–186.

Tooth Surface Loss. By R. Ibbetson andA. Elder (editors). BDJ Books, London,2000 (80pp., £29.95). ISBN 0 904588 66 1.

This book is a compilation of articlesbased on a lecture series by a number ofclinicians who are familiar with the manyfacets of tooth surface loss. The chapterscover the causes of toothwear, itsprevention and control, monitoring,management, restoration and dealing withfailures. The book is well illustrated withrelevant clinical cases and the editorshave worked hard to ensure that thevarious chapters have been presented in alogical order and are related to each other.The novice would be advised to familiarizehis/herself with the territory by firstreading the editors� comments togetherwith their chapters on treatment planning(Chapter 9) and future considerations(Chapter 13). The other chapters arerelevant in their own right; but, by its verynature, a series of articles by differentauthors can weave its way through asubject without developing a clearlyprogressing theme.

Quite rightly, the book gives theimpression that toothwear is a difficultsubject to master; but it also provides apointer towards the fact that some aspectsof the subject are becoming less

complicated. The development ofadhesive techniques have made animportant impact in the management of acondition where crown length is oftencompromised. If a practitioner wanted toread a book that would allow him or her tounderstand tooth surface loss, and to beable to manage all their toothwear caseswith ease, then they might bedisappointed by this book. However,exactly the same problem would arise withall publications on this subject. If, on theother hand, they wanted a realisticappraisal of each aspect of the subject,then this book would certainly provide agood overview.

As stated on the front cover, this is areference book. The index is extremelygood, enabling the reader to find therelevant text on key subjects. The claimthat the book is the authoritative referenceon tooth surface loss could be misleadingin a subject that is currently undergoingdevelopment and change. Experts in thefield are constantly reviewing their clinicalpractice in the light of experience and newevidence. As with all developing subjects,it will be necessary to keep up to date byreading clinical journals; but dentists whoare unfamiliar with the subject would findthis book a useful reference and a goodbasis for continuing education.

L.H. MairLiverpool University Dental Hospital

BOOK REVIEW ABSTRACT

HELP FOR SNORERSThe Durability of Intraoral Devices forSnoring and Sleep Apnoea. D.W. Tyler.Journal of the Canadian DentalAssociation 2000; 66: 464�465.

Although a recent phenomenon, dentaldevices for treating snoring and sleepapnoea are actively promoted by seminars,laboratory mailings and trade magazines,and dentists are encouraged to includethese devices in their clinical practice.

This paper looks at both the durabilityof these devices, and commonlyencountered problems, and urgespractitioners to exercise caution over theiruse. The problems are primarily related tothe extreme forces applied to theappliances during function. Tears in theflanges, loosening of wires, and completefracture of the appliance (whichsubsequently lodged in the patient�sthroat) have all been reported.

Practitioners are advised to inspectsuch appliances carefully, and to institutea regular recall and evaluation programmeto inspect the device for defects. It may bethat different wearers will require differenttypes of appliance, which may only bedetermined after use.

Peter CarrotteGlasgow Dental School