CLINICAL CONTROVERSIES IN ORAL AND MAXILLOFACIAL SURGERY: PART TWO J Oral Maxillofac Surg 63:832-837, 2005 Failed Root Canals: The Case for Apicoectomy (Periradicular Surgery) Thomas von Arx, PD Dr med dent* Apicoectomy involves the surgical management of Treatment Outcome of a tooth with a periapical lesion which cannot be Periradicular Surgery resolved by conventional endodontic treatment Prior to the introduction of microsurgical tech- (root canal 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 root canal treatment 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 dentistry, there has been a within the pulp 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 endodontics. 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