CLINICAL CONTROVERSIES IN ORAL AND MAXILLOFACIAL SURGERY: PART TWO

J Oral Maxillofac Surg 63:832-837, 2005 Failed Root Canals: The Case for () Thomas von Arx, PD Dr med dent*

Apicoectomy involves the surgical management of Treatment Outcome of a with a periapical lesion which cannot be Periradicular Surgery resolved by conventional endodontic treatment Prior to the introduction of microsurgical tech- ( therapy or endodontic retreatment). niques, inconsistent success rates were reported for Because the term “apicoectomy” consists of only periradicular surgery varying between 44% and 90%.2 one aspect (removal of root apex) of a complex Based on a weighted average calculation of reviewed series of surgical procedures, the terms “periapical studies, a success rate of 81% was found for perira- surgery” or “periradicular surgery” are more appro- dicular surgery with simultaneous orthograde treat- priate. The expressions “periapical endodontic sur- ment compared with only 59% for periradicular sur- gery” and “apical microsurgery” are also found in gery without simultaneous orthograde treatment.2 the literature. Interestingly, conventional retreatment of teeth with The objective of periapical surgery is to obtain apical periodontitis showed a weighted average suc- tissue regeneration. This is usually achieved by the cess rate of only 66%, whereas retreatment to correct removal of periapical pathologic tissue and by exclu- radiographically or technically deficient root fillings sion of any irritants within the physical confines of in teeth with periapical disease had a weighted aver- the affected root. age success rate of 95%.2 Considering the limitations of different studies, randomized and prospective clin- ical trials comparing surgical to nonsurgical retreat- ment are needed. Two such studies have been pub- Indications/Contraindications lished.3,4 One study described a higher success rate for surgery after 1 year (58% versus only 28%), al- Because the majority of periapical lesions are asso- though not statistically significant.3 The other study ciated with endodontic pathology, except in cases of reported a statistically significant higher healing rate rare developmental cysts or tumors, the primary goal for surgical retreatment after 1 year, but at the 2-year of treatment is orthograde occlusal approach for root examination, no such difference was found: 60% ver- canal instrumentation and obturation. However, in sus 55%.4 certain cases, endodontic treatment, or retreatment, Following the introduction of microsurgical tech- is not feasible or is contraindicated, and hence an niques, treatment outcomes have improved consider- indication1 for periradicular surgery arises (Table 1). ably and success rates have approached or exceeded In addition to these “objective” indications, we have 90%5-17 (Table 3). These increased success rates are to consider demands by the patient regarding fi- credited to a number of factors that have all con- nances, psychological issues, and treatment time. tributed to the improved outcome of periradicular Contraindications for periradicular surgery are listed surgery: microinstruments, magnification and intraoper- in Table 2. ative inspection, root-end filling materials, and regener- ative techniques.

*Associate Professor, Department of Oral Surgery and Stomatol- ogy, University of Berne, Berne, Switzerland. Microinstruments Address correspondence and reprint requests to Dr von Arx: Root-end cavities have traditionally been prepared Department of Oral Surgery and Stomatology, School of Dental by means of small round burs or inverted cone burs in Medicine, University of Berne, Freiburgstrasse 7, CH-3010 Berne, a microhandpiece. In the early 1990s, sonically or Switzerland; e-mail: [email protected] ultrasonically driven microsurgical retrotips became © 2005 American Association of Oral and Maxillofacial Surgeons commercially available. This new technique of retro- 0278-2391/05/6306-0018$30.00/0 grade cavity preparation has been established as an doi:10.1016/j.joms.2005.02.019 essential adjunct in periradicular surgery.18 Clinically,

832 THOMAS VON ARX 833

tures containing deposits of necrotic tissue and bac- Table 1. INDICATIONS FOR PERIRADICULAR SURGERY (ACCORDING TO ESE 1994) terial toxins have significantly contributed to the better healing success following periapical surgery. Obstructed canal with radiologic findings and/or Careful examination of lingual canals or buccal walls clinical symptoms Extruded material with radiologic findings and/or of retropreparation cavities is most often possible clinical symptoms only with micromirrors, because loupes or micro- Failed when retreatment is scopes do not allow the surgeon to look “around the inappropriate (isthmus tissue, persistent acute corner.” Another magnification device to circumvent symptoms or flare-ups, risk of root fracture) Perforations with radiologic findings and/or clinical such difficulties is the endoscope. Although its appli- symptoms, and where it is impossible to treat from cation has been limited in , there has been a within the cavity growing interest in the use of endoscopy for intraop- Abbreviation: ESE, European Society of Endodontology. erative diagnostics, particularly in periradicular sur- 29,30 Thomas von Arx: Periradicular Surgery. J Oral Maxillofac Surg gery. The endoscope complements the increasing 2005. popularity of applied magnification techniques in dentistry. The advantages of endoscopy in periradicu- lar surgery compared with microscopy include rapid the most relevant advantages are the improved access to root-ends in a limited working space and the and easy adjustment of the viewing angle, and the smaller osteotomy required for surgical access be- direct viewing without the need for the use of dental cause of the angulation and small size of the ret- micromirrors. In addition, the endoscope is a readily rotips.19 However, a number of experimental studies transportable, versatile, and expandable system. have demonstrated other advantages of using mi- Recently, 2 experimental studies have substanti- crotips, such as the preparation of deeper cavities, ated the power of endoscopes for identification of 31,32 and cavities following more closely the original path microstructures. One in vitro study compared the of the root canal.20 The more centered root-end prep- effectiveness of visual enhancements as aids in iden- aration also lessens the risk of lateral perforation. In tifying artificially created dentinal cracks in resected addition, the geometry of the retrotip design does not root-ends. Statistically, the endoscope was signifi- require a beveled root-end resection for surgical ac- cantly superior compared with unaided/corrected vi- cess, thereby decreasing the number of exposed den- sion, loupes, or the microscope.31 tinal tubules and possible leakage through patent tu- The other in vitro study evaluated the diagnostic bules. This is consistent with the criteria established accuracy of endoscopy following root-end resec- for the minimal depth of a retrograde filling with tion and root-end cavity preparation. Endoscopic 21,22 regard to the bevel of the cut root face. Any findings were compared with those obtained with concern about increased formation of cracks or mi- scanning electron microscopy (following root-end crofractures by (ultra)sonic root-end preparation have duplication) serving as the “gold standard.” Speci- been addressed and proved otherwise in several ex- ficity and sensitivity of endoscopic identification of 23-27 perimental studies and in one clinical study. isthmuses, accessory canals, obturation gaps, mi- crofractures, and chipping of cavity margins were Magnification and high, ranging between 73% and 100%.32 It was Intraoperative Inspection concluded that the endoscope is a highly accurate device for intraoperative diagnostics in periradicu- Parallel to the advent of microinstruments, well- lar surgery. focused illumination and magnification have been rec- ommended as a standard of care in periradicular sur- gery.28 Working with loupes or with a surgical microscope has become a widely accepted practice in Table 2. CONTRAINDICATIONS FOR PERIRADICULAR conventional and surgical . It was discov- SURGERY (ACCORDING TO ESE 1994) ered that only the identification and treatment of microscopic findings, such as isthmuses, accessory Local anatomical factors (eg, inaccessible root end) Tooth with inadequate periodontal support canals, or microfractures of the root, would result in Nonrestorable tooth, tooth without function (no periradicular healing or prevent failures, respectively. antagonist, no pillar for removable or fixed prothesis) Rubinstein and Kim11,15 have reported very high suc- Uncooperative patient cess rates after periradicular surgery: 96.5% for the Compromised medical history 1-year and 91.5% for the 5-year examination periods. Abbreviation: ESE, European Society of Endodontology. They thought that with the use of the surgical micro- Thomas von Arx: Periradicular Surgery. J Oral Maxillofac Surg scope, the identification of microanatomical struc- 2005. 834 PERIRADICULAR SURGERY

Table 3. CLINICAL STUDIES ON PERIRADICULAR SURGERY PUBLISHED BETWEEN 1996 AND 2003

Success Author Year n Follow-up Retroprep Retrofill Rate Sumi et al5 1996 157 6 mo to 3 yr Ultrasonic microtip SuperEBA 92.4% Rud et al6 1997 153 (Root canal empty) 2 to 4 yr Shallow concavity Retroplast 81% with ball-shaped diamond bur 153 (Root filling 2 to 4 yr Shallow concavity Retroplast 85% insufficient) with ball-shaped diamond bur 167 (Root filling to 2 to 4 yr Shallow concavity Retroplast 92% apex) with ball-shaped diamond bur Sumi et al7 1997 108 1 to 12 mo Ultrasonic microtip Titanium- 100% inlay and Super EBA Bader and Lejeune8 1998 76 12 mo Ultrasonic microtip IRM 95% 72 12 mo Ultrasonic microtip — 90% ϩ CO2 laser *54 12 mo Conventional bur ϩ IRM 67.5%

CO2 laser *52 12 mo Conventional bur IRM 65% von Arx and Kurt9 1999 43 12 mo Sonic diamond SuperEBA 82% microtip Testori et al10 1999 95 1 to 6 yr (mean 4.6 yr) Ultrasonic microtip SuperEBA 85% *207 1 to 6 yr (mean 4.6 yr) Conventional bur 68% Rubinstein and Kim11 1999 94 (Originally 128) 12 mo Ultrasonic microtip SuperEBA 96.8% ϩ surgical microscope Zuolo et al12 2000 102 12 mo (doubtful cases Ultrasonic diamond IRM 91.2% followed for 4 yr) microtip von Arx et al13 2001 25 (Only molars) 12 mo Sonic diamond SuperEBA 88% microtip Rud et al14 2001 834 (Only mandibular 1.6 to 12.5 yr (mean Shallow concavity Retroplast 92% molars) 4.8 yr) with ball-shaped diamond bur Rubinstein and Kim15 2002 59 (Originally 91) 5 to 7 yr Ultrasonic microtip SuperEBA 91.5% ϩ surgical microscope Maddalone and 2003 120 (Originally 154) 3 yr Ultrasonic microtip SuperEBA 92.5% Gagliani16 Chong et al17 2003 47 2 yr Ultrasonic microtip IRM 87% 61 2 yr Ultrasonic microtip MTA 92% Abbreviations: EBA, ethoxybenzoic acid; IRM, intermediate restorative material; MTA, mineral trioxide aggregate. *Entire entry represents conventional retropreparation technique. Thomas von Arx: Periradicular Surgery. J Oral Maxillofac Surg 2005.

Root-End Filling Materials SuperEBA and IRM both have good experimental and clinical documentation.33 These fortified versions With regard to root-end obturation, the majority of of were found to be more biocom- studies published in the last decade have used a mod- patible and less soluble than other formulations of ified zinc oxide and eugenol–based cement (Super- . They have good antimicrobial EBA [ethoxy benzoic acid] or IRM [intermediate re- 34 storative material]; SuperEBA, Staident International, action and minimal dye leakage. Staines, Middlesex, England; or H. J. Bosworth Com- A new root-end filling material that has received pany, Skokie, IL; IRM, Dentsply/Caulk, York, PA) as a much recent attention is Mineral Trioxide Aggregate retrofilling material (Table 3). Amalgam, glass-iono- (MTA; Dentsply/Tulsa, Tulsa, OK). MTA appears to be mer-cement, or composite retrofilling materials have equal or superior to other root-end filling materials been less frequently reported in recent years. with respect to biocompatibility, dye and bacterial THOMAS VON ARX 835 leakage, marginal adaptation, solubility, and compres- reports have described the successful outcome of sive strength.35 Interestingly, this material also ap- regenerative techniques for treatment of apicomar- pears to induce cementogenesis with new ginal lesions in periapical surgery, but there remains a deposition on the surface of the retrofilling materi- great need for experimental and clinical studies.46 al.36,37 In cases with inadequate hemorrhage control, In a recent clinical study, we have found a fre- MTA has been reported to be superior to other root- quency of 12% of apicomarginal lesions in 100 cases end filling materials. However, the downsides to this subjected to periradicular surgery. In addition to a material are the high cost and the difficult intraoper- standard surgical protocol (root-end resection, root- ative handling of MTA, which has a setting time of end cavity preparation with microtips, SuperEBA as approximately 3 hours. Therefore, care must be ex- retrograde filling), teeth with apicomarginal lesions ercised not to wash out the material after placement. were treated with collagen membranes or an enamel A recently published randomized clinical study com- matrix derivative. Healing outcome in teeth with and paring MTA and IRM with a 2-year follow up has without apicomarginal lesions did not differ signifi- reported success rates of 92% and 87%, respective- cantly (93.2% versus 83.3%) (unpublished data). Ap- ly.17 The difference was not statistically significant. plication of regenerative techniques in teeth with A completely different approach for root-end seal- apicomarginal lesions, or in teeth with through-and- ing has been reported by a Danish group.6,14 A spe- through periapical lesions, might further expand the cially developed and chemically curing composite field of periradicular surgery. resin (Retroplast; Retroplast Trading, Ronne, Den- mark) is used in combination with a dentine-bonding Treatment Alternatives to agent. The resection surface is prepared slightly con- Periapical Surgery cave with a ball-shaped diamond bur. The shallow cavity is etched with EDTA before placing the primer Before planning a periradicular surgery, treatment and the composite resin. The composite resin will alternatives must be discussed with the patient and/or then seal root canals, accessory canals, and isthmuses, the referring . Informed and written consent as well as infractions and exposed tubules. A should be obtained from the patient. prerequisite for this technique is strict hemorrhage control. Nonsurgical Retreatment The Retroplast technique is particularly helpful in cases in which a sufficiently deep root-end cavity Revision of an existing root canal obturation should cannot be prepared, such as teeth with posts or always be considered as a first option. However, pros screws at the resection level, or obliterated root ca- and cons must be carefully evaluated. As discussed in nals (post-trauma, developmental disturbance). the treatment outcome section, healing following conventional retreatment appears to be highly depen- dent on the periapical condition (lesion size), as well Regenerative Techniques as on the anatomy of the endodontium. It has been shown that (pathologic) interactions exist between pulpal and periodontal tissues.38 An Therapy endodontic evident as a periapical radiolu- cency appears to influence periodontal parameters In multirooted molars, resection of a complete root such as probing pocket depth and attachment (mostly mesiobuccal root in maxillary first molars) or loss.39-42 It has also been demonstrated that a signifi- tooth separation (hemisection of mandibular first or cant correlation exists between marginal periodontal second molars) should be considered as treatment and apical healing following periapical surgery.43 options. The procedure is indicated in particular for A challenging problem in periapical surgery re- roots with compromised periodontal support or deep mains the loss of buccal with partial or complete decay. root exposure (apicomarginal lesions). It has been shown that healing outcome in periapical surgery is Tooth Extraction related to the condition of the buccal bone plate.44,45 Epithelial downgrowth along the denuded buccal It is generally accepted that extraction of a tooth root surface is considered as a major negative factor with periapical pathology will eventually result in preventing successful healing in such cases. healing. However, subsequent vertical and/or hori- Although regenerative techniques have become a zontal bone loss may lead to soft and hard tissue standard of care in and implant den- deficiencies. This is of particular concern in the grow- tistry, these techniques have yet to be established in ing child or in the anterior maxilla with high esthetic endodontic surgery. A substantial number of case demands. Whenever possible, teeth should be sal- 836 PERIRADICULAR SURGERY vaged to preserve the unique scalloped anatomy of 9. von Arx T, Kurt B: Root-end cavity preparation after apicoec- hard and soft tissues around natural teeth or to avoid tomy using a new type of sonic and diamond-surfaced retrotip: A 1-year follow-up study. J Oral Maxillofac Surg 57:656, 1999 multiunit edentulous spaces in the anterior maxilla, a 10. Testori T, Capelli M, Milani S, et al: Success and failure in situation that is extremely difficult to manage from an periradicular surgery. A longitudinal retrospective analysis. esthetic perspective. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 87:493, 1999 11. Rubinstein RA, Kim S: Short-term observation of the results of endodontic surgery with the use of a surgical operation micro- Limitations of Periradicular Surgery scope and Super-EBA as root-end filling material. J Endod 25:43, 1999 In contrast to other specialties in dentistry, that is, 12. Zuolo ML, Ferreira MOF, Gutmann JL: Prognosis in periradicu- implant dentistry, long-term studies (duration of at lar surgery: A clinical prospective study. Int Endod J 33:91, least 5 years, dropout rate below 10%) are scarce. In 2000 13. von Arx T, Gerber C, Hardt N: Periradicular surgery of molars: addition, periradicular surgery only implies the surgi- A prospective clinical study with a one-year follow-up. Int cal treatment of a short part of the tooth, that is, the Endod J 34:520, 2001 root end. Periradicular surgery does not address the 14. Rud J, Rud V, Munksgaard EC: Periapical healing of mandibular treatment of coronal leakage, and therefore, a certain molars after root-end sealing with dentine-bonded composite. Int Endod J 34:285, 2001 risk remains for periradicular reinfection. Conse- 15. Rubinstein RA, Kim S: Long-term follow-up of cases considered quently, indications and treatment alternatives must healed one year after apical microsurgery. J Endod 28:378, be evaluated carefully and thoroughly. 2002 In conclusion, 1) strict case selection based on 16. Maddalone M, Gagliani M: Periapical endodontic surgery: A 3-year follow-up study. Int Endod J 36:193, 2003 clinical and radiographic parameters is of utmost 17. Chong BS, Pitt Ford TR, Hudson MB: A prospective clinical importance in periradicular surgery; 2) the advent study of Mineral Trioxide Aggregate and IRM when used as of microsurgical principles, ie, the use of microin- root-end filling materials in endodontic surgery. Int Endod J 36:520, 2003 struments, illumination, and magnification, have 18. Carr GB: Ultrasonic root end preparation. Dent Clin N Am simplified the surgical technique, and have contrib- 41:541, 1997 uted to higher success rates in periradicular sur- 19. von Arx T, Kurt B, Ilgenstein B, et al: Preliminary results and gery; and 3) regenerative techniques should be con- analysis of a new set of sonic instruments for root-end cavity preparation. Int Endod J 31:32, 1998 sidered as adjunctive treatment options in 20. von Arx T, Walker WA: Microsurgical instruments for root-end periradicular surgery. cavity preparation following apicoectomy: A literature review. Endod Dent Traumatol 16:47, 2000 21. Tidmarsh BG, Arrowsmith MG: Dentinal tubules at the root Acknowledgments ends of apicected teeth: A scanning electron microscopic study. Int Endod J 22:184, 1989 The author thanks Dr Alvin Yeo, BDS, MS, Department of Oral 22. Gilheany PA, Figdor D, Tyas MJ: Apical dentin permeability and Surgery and Stomatology, University of Bern, Switzerland, and De- partment of , National Dental Center, Singa- microleakage associated with root end resection and retro- pore, for proofreading the manuscript. grade filling. J Endod 20:22, 1994 23. Lloyd A, Jaunberzins A, Dummer PMH, et al: Root-end cavity preparation using MicroMega sonic retro-prep tip. SEM analy- sis. Int Endod J 29:295, 1996 24. Beling KL, Marshall JG, Morgan LA, et al: Evaluation for cracks References associated with ultrasonic root-end preparation of gutta-percha 1. ESE/European Society of Endodontology: Consensus report of filled canals. J Endod 23:323, 1997 the European Society of Endodontology on quality guidelines 25. Waplington M, Lumley PJ, Walmsley AD: Incidence of root face for endodontic treatment. Int Endod J 27:115, 1994 alteration after ultrasonic retrograde cavity preparation. Oral 2. Hepworth MJ, Friedman S: Treatment outcome of surgical and Surg Oral Med Oral Pathol Oral Radiol Endod 83:387, 1997 non-surgical management of endodontic failures. J Can Dent 26. Calzonetti KJ, Iwanowski T, Komorowski R, et al: Ultrasonic Assoc 63:364, 1997 root end cavity preparation assessed by an in situ impression 3. Danin J, Strömberg T, Forsgren H, et al: Clinical management of technique. Oral Surg Oral Med Oral Pathol Oral Radiol Endod non-healing periradicular pathosis. Surgery versus endodontic 85:210, 1998 retreatment. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 27. Morgan LA, Marshall JG: A scanning electron microscopic 82:213, 1996 study of in vivo ultrasonic root-end preparations. J Endod 4. Kvist T, Reit C: Results of endodontic re-treatment: A random- 25:567, 1999 ized clinical study comparing surgical and nonsurgical proce- 28. Kim S: Principles of endodontic microsurgery. Dent Clin North dures. J Endod 25:814, 1999 Am 41:481, 1997 5. Sumi Y, Hattori H, Hayashi K, et al: Ultrasonic root-end prep- aration: Clinical and radiographic evaluation of results. J Oral 29. Bahcall JK, Di Fiore PM, Poulakidas TK: An endoscopic tech- Maxillofac Surg 54:590, 1996 nique for endodontic surgery. J Endod 25:132, 1999 6. Rud J, Rud V, Munksgaard EC: Long-term evaluation of retro- 30. von Arx T, Hunenbart S, Buser D: Endoscope- and video- grade root filling with dentin-bonded resin composite. J Endod assisted endodontic surgery. Quintessence Int 33:255, 2002 22:90, 1996 31. Slaton CC, Loushine RJ, Weller RN, et al: Identification of 7. Sumi Y, Hattori H, Hayashi K, et al: Titanium inlay—a new resected root-end dentinal cracks: A comparative study of vi- root-end filling material. J Endod 23:121, 1997 sual magnification. J Endod 29:519, 2003 8. Bader G, Lejeune S: Prospective study of two retrograde end- 32. von Arx T, Montagne D, Zwinggi C, et al: Diagnostic accuracy

odontic apical preparations with and without the use of CO2 of endoscopy in periradicular surgery—a comparison with laser. Endod Dent Traumatol 14:75, 1998 scanning electron microscopy. Int Endod J 36:691, 2003 THOMAS VON ARX 837

33. Johnson BR: Considerations in the selection of a root-end filling 40. Jansson L, Ehnevid H, Lindskog S, et al: Radiographic attach- material. Oral Surg Oral Med Oral Pathol Oral Radiol Endod ment in periodontitis-prone teeth with endodontic infection. J 87:398, 1999 Periodontol 64:947, 1993 34. Haumann CHJ, Love RM: Biocompatibility of dental materials 41. Ehnevid H, Jansson L, Lindskog S, et al: Periodontal healing in used in contemporary endodontic therapy: A review. Part 2. teeth with periapical lesions. A clinical retrospective study. Root-canal filling materials. Int Endod J 36:147, 2003 J Clin Periodontol 20:254, 1993 35. Torabinejad M, Pitt Ford TR: Root-end filling material: A re- 42. Jansson L, Ehnevid H, Lindskog S, et al: The influence of view. Endod Dent Traumatol 12:161, 1996 endodontic infection on progression of marginal bone loss in 36. Torabinejad M, Pitt Ford TR, McKendry DJ, et al: Histologic periodontitis. J Clin Periodontol 22:729, 1995 assessment of Mineral Trioxide Aggregate as a root-end filling 43. Jansson L, Sandstedt P, Laftman AC, et al: Relationship between in monkeys. J Endod 23:225, 1997 apical and marginal healing in periradicular surgery. Oral Surg 37. von Arx T, Britain S, Cochran DL, et al: Healing of periapical Oral Med Oral Pathol Oral Radiol Endod 83:596, 1994 lesions with complete loss of the buccal bone plate: A histo- 44. Hirsch JM, Ahlström U, Henrikson PA, et al: Periapical surgery. logical study in the canine . Int J Periodontics Restor- Int J Oral Surg 8:173, 1979 ative Dent 23:157, 2003 45. Skoglund A, Persson G: A follow-up study of apicoectomized 38. Zehnder M, Gold SI, Hasselgren G: Pathologic interactions in teeth with total loss of the buccal bone plate. Oral Surg Oral pulpal and periodontal tissues. J Clin Periodontol 29:663, Med Oral Pathol 59:78, 1985 2002 46. von Arx T, Cochran DL: Rationale for the application of the 39. Jansson L, Ehnevid H, Lindskog S, et al: Relationship between GTR principle using a barrier membrane in endodontic sur- periapical and periodontal status. A clinical retrospective gery: A proposal of classification and literature review. Int J study. J Clin Periodontol 20:117, 1993 Periodont Restor Dent 21:127, 2001