References

Rud J, Andreasen JO, Jensen JE. A follow-up study of 1,000 cases treated by endodontic surgery. Int J Oral Surg. 1972; 1:215-28 https://doi.org/10.1016/s0300-9785(72)80014-0
von Arx T, Gerber C, Hardt N. Periradicular surgery of molars: a prospective clinical study with a one-year follow-up. Int Endod J. 2001; 34:520-525 https://doi.org/10.1046/j.1365-2591.2001.00427.x
Maddalone M, Gagliani M. Periapical endodontic surgery: a 3-year follow-up study. Int Endod J. 2003; 36:193-198 https://doi.org/10.1046/j.1365-2591.2003.00642.x
Rahbaran S, Gilthorpe MS, Harrison SD, Gulabivala K. Comparison of clinical outcome of periapical surgery in endodontic and oral surgery units of a teaching dental hospital: a retrospective study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2001; 91:700-709 https://doi.org/10.1067/moe.2001.114828
Setzer FC, Kohli MR, Shah SB Outcome of endodontic surgery: a meta-analysis of the literature – Part 2: Comparison of endodontic microsurgical techniques with and without the use of higher magnification. J Endod. 2012; 38:1-10 https://doi.org/10.1016/j.joen.2011.09.021
Zuolo ML, Ferreira MO, Gutmann JL. Prognosis in periradicular surgery: a clinical prospective study. Int Endod J. 2000; 33:91-98 https://doi.org/10.1046/j.1365-2591.2000.00263.x
Quality guidelines for endodontic treatment: consensus report of the European Society of Endodontology. Int Endod J. 2006; 39:921-930 https://doi.org/10.1111/j.1365-2591.2006.01180.x
Castro VM, Katz JO, Hardman PK In vitro comparison of conventional film and direct digital imaging in the detection of approximal caries. Dentomaxillofac Radiol. 2007; 36:138-42 https://doi.org/10.1259/dmfr/15558921
White SC, Yoon DC. Comparative performance of digital and conventional images for detecting proximal surface caries. Dentomaxillofac Radiol. 1997; 26:32-38 https://doi.org/10.1038/sj.dmfr.4600208
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Rushton VE, Horner K. A comparative study of radiographic quality with five periapical techniques in general dental practice. Dentomaxillofac Radiol. 1994; 23:37-45 https://doi.org/10.1259/dmfr.23.1.8181658
Davies A, Mannocci F, Mitchell P The detection of periapical pathoses in root filled teeth using single and parallax periapical radiographs versus cone beam computed tomography - a clinical study. Int Endod J. 2015; 48:582-592
Roberts J, Drage N, Davies J, Thomas D. Effective dose from cone beam CT examinations in dentistry. Br J Radiol. 2009; 82:35-40
Von Arx T, Jensen SS, Hänni S. Clinical and radiographic assessment of various predictors for healing outcome 1 year after periapical surgery. J Endod. 2007; 33:123-128
Lindeboom J, Frenken J, Tuk J, Kroon F. A randomized prospective controlled trial of antibiotic prophylaxis in intraoral bone-grafting procedures: preoperative single-dose penicillin versus preoperative single-dose clindamycin. Int J Oral Maxillofac Surg. 2006; 35:433-436
Lawler B, Sambrook PJ, Goss AN. Antibiotic prophylaxis for dentoalveolar surgery: is it indicated?. Aust Dent J. 2005; 50:S54-S59
Collins SL, Moore RA, McQuay HJ Single dose oral ibuprofen and diclofenac for postoperative pain. Cochrane Database Syst Rev. 2000; (2) https://doi.org/10.1002/14651858.CD001548
Jackson DL, Moore PA, Hargreaves KM. Preoperative nonsteroidal anti-inflammatory medication for the prevention of postoperative dental pain. J Am Dent Assoc. 1989; 119:641-647
Baxendale B, Vater M, Lavery K. Dexamethasone reduces pain and swelling following extraction of third molar teeth. Anaesthesia. 1993; 48:961-964
Lin S, Levin L, Emodi O Etodolac versus dexamethasone effect in reduction of postoperative symptoms following surgical endodontic treatment: a double-blind study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006; 101:814-817 https://doi.org/10.1016/j.tripleo.2005.08.039
Savage MG, Henry MA. Preoperative nonsteroidal anti-inflammatory agents: review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2004; 98:146-152 https://doi.org/10.1016/j.tripleo.2004.01.012
Moore PA, Werther JR, Seldin EB, Stevens CM. Analgesic regimens for third molar surgery: pharmacologic and behavioral considerations. J Am Dent Assoc. 1986; 113:739-744
Balbuena L, Stambaugh KI, Ramirez SG, Yeager C. Effects of topical oral antiseptic rinses on bacterial counts of saliva in healthy human subjects. Otolaryngol Head Neck Surg. 1998; 118:625-9
Martin M, Nind D. Use of chlorhexidine gluconate for pre-operative disinfection of apicectomy sites. Br Dent J. 1987; 162
Sveen K. Effect of the addition of a vasoconstrictor to local anesthetic solution on operative and postoperative bleeding, analgesia and wound healing. Int J Oral Surg. 1979; 8:301-6
Sisk AL. Comparison of etidocaine and lidocaine for control of intra-and post-operative bleeding and pain. J Oral Maxillofac Surg. 1986; 44:16-20
Kim S, Rethnam S. Hemostasis in endodontic microsurgery. Dent Clin North Am. 1997; 41:499-511
Witherspoon D, Gutmann J. Haemostasis in periradicular surgery. Int Endod J. 1996; 29:135-149
Crout RJ, Koraido G, Moore PA. A clinical trial of long-acting local anesthetics for periodontal surgery. Anesth Prog. 1990; 37:194-198
Von Arx T, Walker W. Microsurgical instruments for root-end cavity preparation following apicoectomy: a literature review. Dent Traumatol. 2000; 16:47-62
Setzer FC, Shah SB, Kohli MR Outcome of endodontic surgery: a meta-analysis of the literature—part 1: comparison of traditional root-end surgery and endodontic microsurgery. J Endod. 2010; 36:1757-1765
Rubinstein RA, Kim S. Long-term follow-up of cases considered healed one year after apical microsurgery. J Endod. 2002; 28:378-383
Chindia ML, Valderhaug J. Periodontal status following trapezoidal and semilunar flaps in apicectomy. East Afr Med J. 1995; 72:564-567
Velvart P, Peters CI, Peters OA. Soft tissue management: flap design, incision, tissue elevation, and tissue retraction. Endod Topics. 2005; 11:78-97
Velvart P, Ebner-Zimmermann U, Ebner J. Comparison of papilla healing following sulcular full-thickness flap and papilla base flap in endodontic surgery. Int Endod J. 2003; 36:653-659
Lin L, Gaengler P, Langeland K. Periradicular curettage. Int Endod J. 1996; 29:220-227
Hess W, Zürcher E, Dolamore WH.New York: William Wood; 1925
Wada M, Takase T, Nakanuma K Clinical study of refractory apical periodontitis treated by apicectomy Part 1. Root canal morphology of resected apex. Int Endod J. 1998; 31:53-56
Gutmann J, Ford TP. Management of the resected root end: a clinical review. Int Endod J. 1993; 26:273-383
Gilheany PA, Figdor D, Tyas MJ. Apical dentin permeability and microleakage associated with root end resection and retrograde filling. J Endod. 1994; 20:22-26
Nedderman TA, Hartwell GR, Portell FR. A comparison of root surfaces following apical root resection with various burs: scanning electron microscopic evaluation. J Endod. 1988; 14:423-427
Kim S, Kratchman S. Modern endodontic surgery concepts and practice: a review. J Endod. 2006; 32:601-623
Vickers FJ, Baumgartner JC, Marshall G. Hemostatic efficacy and cardiovascular effects of agents used during endodontic surgery. J Endod. 2002; 28:322-323
Lemon RR, Steele PJ, Jeansonne BG. Ferric sulfate hemostasis: effect on osseous wound healing. I. Left in situ for maximum exposure. J Endod. 1993; 19:170-173
Von Arx T, Jensen S, Hänni S, Schenk R. Haemostatic agents used in periradicular surgery: an experimental study of their efficacy and tissue reactions. Int Endod J. 2006; 39:800-808
Carr GB. Ultrasonic root end preparation. Dent Clin North Am. 1997; 41:541-554
Gutmann J, Saunders W, Nguyen L Ultrasonic root-end preparation Part 1. SEM analysis. Int Endod J. 1994; 27:318-324
Waplington M, Lumley PJ, Walmsley AD. Incidence of root face alteration after ultrasonic retrograde cavity preparation. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1997; 83:387-392
Peters C, Peters O, Barbakow F. An in vitro study comparing root-end cavities prepared by diamond-coated and stainless steel ultrasonic retrotips. Int Endod J. 2001; 34:142-148
Dorn SO, Gartner AH. Retrograde filling materials: a retrospective success-failure study of amalgam, EBA, and IRM. J Endod. 1990; 16:391-393
Niederman R, Theodosopoulou J. A systematic review of in vivo retrograde obturation materials. Int Endod J. 2003; 36:577-585
Chong B, Pitt Ford T, Hudson M. A prospective clinical study of mineral trioxide aggregate and IRM when used as root-end filling materials in endodontic surgery. Int Endod J. 2003; 36:520-526
Torabinejad M, Hong C-U, Lee S-J Investigation of mineral trioxide aggregate for root-end filling in dogs. J Endod. 1995; 21:603-608
Torabinejad M, Corr R, Handysides R, Shabahang S. Outcomes of nonsurgical retreatment and endodontic surgery: a systematic review. J Endod. 2009; 35:930-937
Nuñez C, Bosomworth H, Field C Biodentine and MTA induce similar cellular responses in a fibroblast cell line. J Endod. 2014; 40:406-411
Maguire H, Torabinejad M, McKendry D Effects of resorbable membrane placement and human osteogenic protein-1 on hard tissue healing after periradicular surgery in cats. J Endod. 1998; 24:720-725
Garrett K, Kerr M, Hartwell G The effect of a bioresorbable matrix barrier in endodontic surgery on the rate of periapical healing: an in vivo study. J Endod. 2002; 28:503-506
Tsesis I, Rosen E, Tamse A Effect of guided tissue regeneration on the outcome of surgical endodontic treatment: a systematic review and meta-analysis. J Endod. 2011; 37:1039-1045
Taschieri S, Del Fabbro M, Testori T Efficacy of guided tissue regeneration in the management of through-and-through lesions following surgical endodontics: a preliminary study. Int J Period Rest Dent. 2008; 28
Velvart P, Peters CI. Soft tissue management in endodontic surgery. J Endod. 2005; 31:4-16
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Gabrielli F, Potenza C, Puddu P Suture materials and other factors associated with tissue reactivity, infection, and wound dehiscence among plastic surgery outpatients. Plastic Reconstruct Surg. 2001; 107:38-45
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Selvig KA, Biagiotti GR, Leknes KN, Wikesjö U. Oral tissue reactions to suture materials. Int J Periodontol Rest Dent. 1998; 18:474-487
Heitz F, Heitz-Mayfield L, Lang N. Effects of post-surgical cleansing protocols on early plaque control in periodontal and/or peri-implant wound healing. J Clin Periodontol. 2004; 31:1012-1018

Endodontic surgery. Part 2: surgical root canal re-treatment

From Volume 49, Issue 11, December 2022 | Pages 880-887

Authors

Robert Smith

BDS, MSc, MFDS RCS, MFDTEd, BDS, MSc, MEndoRCS, MFDS RCS, FDTFEd,

Enhanced Practitioner, Defence Primary Healthcare (Dental), Defence Centre for Rehabilitative Dentistry

Articles by Robert Smith

Email Robert Smith

Graeme Bryce

BDS, MSc, MEndoRCS, MRD RCPSG, FDS (Rest Dent), FDTFEd,

Consultant in Restorative Dentistry, Centre for Restorative Dentistry, Defence Primary Health Care (Dental), Aldershot

Articles by Graeme Bryce

Email Graeme Bryce

Geoffrey St George

BDS, DGDP (UK), MSc, FDS RCS, FDS (Rest Dent)

Consultant in Restorative Dentistry

Articles by Geoffrey St George

Poonam Kalsi

BDS (Hons), MSc, MJDF RCS, FDS (Rest Dent)

Consultant in Restorative Dentistry, Guy's and St Thomas' NHS Foundation Trust, London

Articles by Poonam Kalsi

Abstract

Surgical root canal re-treatment (SRCReT), or root-end surgery, is the most commonly undertaken surgical endodontic technique. Approaches to SRCReT differ, with a variety of different protocols described and varied success rates reported. In the second part of this two-part series, the current scientific literature is examined and clinical examples are given to offer guidance for the optimal protocol for SRCReT.

CPD/Clinical Relevance: SRCReT is a procedure which may facilitate the treatment of disease of endodontic origin which is not amenable to management with orthograde non-surgical root canal treatment.

Article

In Part 1 of this series, a general overview of endodontic surgery was discussed. The second article evaluates the optimal way to perform SRCReT, the commonest endodontic surgical procedure, which is a long-established method of treatment for apical periodontitis when conventional root canal treatment (RCT) has failed and non-surgical root canal re-treatment (NSRCReT) is impractical.1 As discussed in Part 1, SRCReT success rates are reported to range between 37% to over 90%15 with a number of general and local factors responsible for this wide variation. A strict surgical protocol improves the prognosis of treatment.4,6 Guidelines for the provision of SRCReT (American Association of Endodontists, British Endodontic Society Quality Guidelines, Royal College of Surgeons of England) are generic and do not adequately detail or illustrate their proposed approaches. This article uses published scientific literature to produce a protocol for SRCReT, with inferences drawn that can be applied to other endodontic surgical techniques.

Surgical root canal re-treatment

Surgical procedures can generally be broken down into three phases: pre-operative; intra-operative; and post-operative procedures. The pre-operative phase for SRCReT should include a thorough history, clinical and radiographic assessment, diagnoses, treatment planning, consent, prescription of prophylactic drugs, the disinfection of the operative site and local anaesthesia. The intra-operative phase includes magnification and visualization, soft tissue management, osteotomy, haemostasis, root-end resection, root canal root-end preparation, obturation of the prepared root-end, curettage, regenerative procedures and wound closure. The post-operative phase includes pain control, post-operative instructions, pre-emptive management of possible complications, suture removal and review.

Pre-operative phase

History

This should include routine history, such as medical, and more specific aspects, such as the history of treatment to the tooth, previous trauma, pain history and decementation of restorations, for instance, post crowns, which may indicate poor restorative prognosis or root fracture.

Clinical assessment

A consultation should include a thorough clinical examination and special tests, as per best practice guidelines.7

Radiographic assessment

Both digital and wet film parallel long-cone peri-apical radiographic images can be used for pre-operative assessment,8,9 although the effective dose is lower for digital radiographs.10 The taking of two angled peri-apical views provides greater information of the surgical site than a single view.11 3D imaging using a small volume cone beam computerized tomography (CBCT) has also been shown to be useful in SRCReT because it can be more effective than peri-apical radiography in diagnosing apical lesions,12 assessing adjacent anatomical structures and planning extensive surgery (Figure 1). However, a balance must be struck between radiation dose limitation and obtaining sufficient information for diagnosis and treatment planning.13

Figure 1. CBCT view of radicular cyst encroaching on the incisive nerve foramen.

Diagnosis and treatment planning

A diagnosis must be made and explained to the patient to justify intervention/non-intervention. Indications and contra-indications for SRCReT are well established7 and are listed in Table 1.


Indications for SRCReT Contraindications for SRCReT
Signs and symptoms (including radiographic findings) that indicate a diagnosis of apical periodontitis associated with a root canal that is not negotiable (the obstruction cannot be bypassed, or removal poses too great a risk to the root) Systemic illness contraindicating the undertaking of minor surgical procedures. Patient physically or psychologically unable to tolerate treatment
Extruded root filling material with radiographic findings and/or signs and symptoms of apical periodontitis Local anatomical factors, such as: unusual bony anatomy; root ends lying in close proximity to the nasal cavity, maxillary sinus and neurovascular bundles; posterior teeth with inaccessible root ends, dental implants in close proximity to the surgical site
The emergence, or persistence, of disease following root canal treatment where further orthograde root canal re-treatment is contraindicated (suspected aberrant apical anatomy or teeth with well-fitting restorations) Teeth with a hopeless restorative prognosis, for instance, a vertically root-fractured tooth

Consent

The consent process should provide the patient with a detailed explanation of the surgical procedure, the advantages/disadvantages and risks of the proposed treatment and alternative treatment options. Common risks include bleeding, swelling, pain, gingival recession, scarring of mucosa, a transient increase in mobility of teeth, failure of treatment, and devascularization of adjacent roots contained within the lesion.

Use of prophylactic medications

No correlation has been found between prophylactic antibiotic provision and healing following SRCReT,14 or elimination of post-operative wound healing complications.15,16 The routine prescription of antibiotics cannot therefore be recommended. Single pre-operative doses of a non-steroidal anti-inflammatory drug (NSAID) have been shown to be effective at reducing post-operative pain for general surgical procedures17,18 and prophylactic steroids have been shown to reduce post-extraction pain.19 For SRCReT, a pre-operative dose of 8 mg dexamethasone followed by two single 4-mg doses on the first and second days post-operatively has been found to reduce post-operative pain.20 However, presently, there is insufficient evidence to support the use of single-dose steroids over their NSAID counterparts. Given the availability and well-tolerated nature of NSAIDs, a single pre-operative dose of 400 mg ibuprofen21 or 1000 mg paracetamol is advised as part of any pre-operative protocol.22

Disinfection of the intra-oral operative site

Pre-operative rinsing with chlorhexidine gluconate may inhibit the growth of bacteria in saliva for up to 4 hours post-operatively23 and reduce the bacterial load around apicectomy sites by up to 94%.24 Patients should rinse pre-operatively for 1 minute, using 10 ml of a 0.2% chlorhexidine gluconate-containing mouthwash. The application of chlorhexidine gluconate-dampened gauze to the relevant oral tissues should also be considered.24

Local anaesthesia

The use of local anaesthetic containing a vasoconstrictor improves both intra-operative haemostatic control as well as the depth and the duration of anaesthesia.25 There is insufficient evidence to support the superiority of any particular local anaesthetic. However, improved control of intra-operative bleeding is achieved with increased adrenaline concentration.26,27 Commercially available 2% lidocaine with 1:80,000 adrenaline can be recommended28 although alternatives exist, including formulations of articaine, prilocaine and mepivacaine. The long-acting local anaesthetic bupivacaine, when combined with 1:200,000 adrenaline, is an effective local anaesthetic. It has the additional benefit of a long duration, which reduces post-operative pain, but at the expense of an increase in the amount of intra-operative bleeding.29

Intra-operative phase

Magnification and visualization

Microsurgical techniques, undertaken with high magnification, offer a number of advantages, including improved detection of root canal features, such as cracks and accessory anatomy.30 The use of operating microscopes, combined with microsurgical instruments, can improve SRCReT outcomes.31,32 An operating microscope or, at the very least, magnifying loupes with a direct light source should be employed for SRCReT.

Soft tissue management

A number of muco-periosteal flap designs have been advocated for use in SRCReT and these include semi-lunar, submarginal, as well as different types of full-thickness flaps that employ either intrasulcular or papilla-based incisions. These have been combined with vertical relieving incisions to allow better access to the surgical site.33,34 Flap designs that use an intrasulcular or papilla-based incision, combined with appropriate relieving incisions are preferred over a semi-lunar approach because there is improved visualization, reduced intra-operative bleeding, the incision line does not encroach upon the osteotomy site, and there is reduced post-operative scarring.34 To facilitate adequate visualization and management of the surgical site, the flap should be extended at least one tooth either side of the estimated extent of the peri-radicular lesion. Greater debate surrounds the optimal method of incision at the gingival margin. Papilla-based incisions are better at preserving the vertical height of the papillae when compared to their intra-sulcular counterparts35 because of reduced vascular and connective tissue damage to the most coronal part of the papilla. Closer adaptation of the flap margin to the adjacent fixed tissue, which facilitates primary healing, is also easier to achieve. However, this incision may impair the visualization of the proximal marginal aspects of the root and this should be taken into consideration when planning the flap design. When maintenance of papillae height is essential for aesthetic reasons, a papilla-based incision is advocated. A full thickness intra-sulcular incision would be the preferred approach when full visualization of a tooth/alveolar bone is essential (to rule out the presence of a crack or perforation). Either a 15C or micro-surgical blade is sufficiently small to make precise incisions (Figure 2). Retraction should commence at the base of the relieving incision, rotating a periosteal elevator (such as a Buser) against the bone and advancing the instrument in small movements to ensure separation of the periosteum from the bone. The flap should be kept moist throughout the procedure using sterile saline.

Figure 2. Papillae preservation incision for SRCReT UR1 UL1. (a) Pre-operative. (b) Primary 1.5-mm deep split-thickness incision, angled at 90° to the surface of the gingivae and meeting the papillae gingival margins at 90°. (c) Secondary full-thickness incision, retracing the original incision at a much steeper angle and contacting bone using a 15c blade to (d) connect the initial incisions and (e) for the vertical relieving incision and elevation of rectangular-shaped flap.

Alveolar bone removal

The amount of bone removal to facilitate access for curettage, root resection and root-end preparation depends on the size of the peri-apical lesion. Larger lesions are more likely to have incurred buccal cortical plate erosion, helping to assist with the identification of the root-end. With smaller lesions, direct measurements from radiographs and careful orientation are needed to locate the site to start the osteotomy preparation. Prospective studies with good outcomes have employed rear-venting high-speed handpieces (that avoid contamination of the surgical site with handpiece oil and the theoretical possibility of surgical emphysema), and use of round tungsten carbide burs for the osteotomy phase of the treatment.6 A contra-angle rear-venting high speed surgical handpiece with a surgical Lindemann bone bur (or rose head bur), cooled with saline, facilitates good visualization for precise removal of alveolar bone (Figure 3). Alternatively, surgical motors or piezoelectric surgical units (eg Mectron, Carrasco, Italy) can create the alveolar window, while also offering the flexibility to resect and retro-prepare the root-end (Figure 4). Initial preparation of the bony window should be conservative, because access will be increased following root resection, with evaluation and further enlargement carried out if required. Minimizing the osteotomy site reduces soft tissue invasion of the bony cavity, which may impair bone healing.

Figure 3. Use of a rear-venting high speed handpiece with tungsten carbide bur for creation of the alveolar window and apical root resection.
Figure 4. Use of a piezoelectrical surgical unit for (a) precise bone removal and (b) creation of an alveolar window.

Curettage of the lesion

Different instruments may be used to fully access and curette the irregular walls of the bony crypt. Suitable instruments include Lucas surgical curettes, periodontal curettes and spoon excavators. A systematic approach to curettage should be undertaken, with scraping and soft tissue removal carried out in a uniform direction from one wall of the lesion to the other. Further curettage may be accomplished once the root tip is removed and access is improved. As with any excisional procedure, a specimen sample of the lesion should, if possible, be sent for histopathological examination to confirm the diagnosis. Healing occurs if the bulk of an inflammatory lesion is removed, even in the presence of residual soft tissue tags.36

Root-end resection

Resection of the apical 3 mm of the root tip removes the majority of accessory anatomy37,38 and facilitates access for both further curettage and retro-preparation of the root canal space.39 The resection angle should be at 90 degrees to the long axis of the root as this reduces the number of exposed (and potentially) infected dentinal tubules40 that result when a traditional bevelled resection is employed. A surgical high-speed handpiece, using either a diamond or tungsten carbide bur40,41 can achieve this angle of resection (Figure 3).4,6,42 Methylene blue dye (Vista-Blue, Vista Dental Products, Racine, USA) can be used to stain the resected root surface to aid the identification of cracks, unfilled canals and also help differentiate the root from adjacent alveolar bone.42 Cracks can initiate and propagate in an apico-coronal direction or corono-apical direction. Where a crack communicates with the oral cavity, the chance of re-infection of root canal space is high, and failure of the SRCReT is likely, in which case arrangements to extract the tooth +/- subsequent bone grafting +/- prosthetic replacement should be made. However, in cases where the crack is within the apical half of the tooth, it may be possible to resect away the cracked portion of the root. Where further root resection is undertaken consideration needs to be given to the effect of further reducing the crown–root ratio, and the effect of this on the restorative prognosis for the tooth.

Intra-operative haemostasis

Multiple materials have been tested to control intra-operative haemostasis, including mechanical agents (bone wax, calcium sulphate), absorbable haemostatic agents (Surgicel, Ethicon Inc, San Lorenzo, Puerto Rico), chemical agents (aluminium sulphate, ferric sulphate, adrenaline-soaked pellets) and collagenous based materials such as Avitene (Davol Inc, Warwick, USA) (bovine collagen fibrils).28 Consideration should be given to the prolonged inflammation that these agents may initiate within the surgical site.28,4345 Adrenaline (local anaesthetic) soaked sterile cotton pellets offer a readily available and safe means of controlling bleeding, though any stray fragments of cotton fibre in the surgical site must be sought and removed under the operating microscope prior to surgical closure.

Root-end preparation

Ultrasonic tips are smaller than conventional rotary handpieces and offer better visualization of the root-end, providing an effective method of removing root filling materials and preparing the apical 3mm of the canal space.32,46,47 Although no conclusive evidence supports any particular ultrasonic regimen a low-power setting, combined with a diamond-tipped instrument, may help to avoid crazing of the root-end surface.48,49 Longer-length ultrasonic file tips allow deeper preparation of the root canal space (Figure 5), although little is known about the influence of this on outcome. Following preparation, the root-end cavity should be carefully re-examined for the presence of residual debris, damage and cracks (Figure 6) then rinsed with sterile saline and dried with paper points.

Figure 5. Retro-preparation of the root-end cavity with (a) 3-mm and (b) 6-mm ultrasonic tips.
Figure 6. View of the resected and retro-prepared root canals.

Cavity obturation

A host of materials have been employed with SRCReT obturation and include amalgam, gutta percha, zinc oxide–eugenol-based materials such as Super EBA (Bosworth Company, Myerstown, USA) and IRM (Dentsply Caulk, Milford, USA),50 composite, glass ionomer and mineral trioxide aggregate (MTA). Amalgam has been negatively associated with outcome and should be avoided,51 while high success rates have been associated with IRM, EBA and MTA.50,52 Favourable properties of MTA include its reduced peri-radicular inflammatory response and the cementum deposition that occurs over its surface.53,54 More recently, tricalcium silicate cements (Biodentine (Septodont, Saint-Maur-des-Fossés, France) and putties have been advocated for use in endodontic surgery due to having a similar biocompatibility as MTA,55 but with improved handling qualities. Either MTA or tricalcium silicate cements can be placed into the prepared canal space using a Lee Carver and MTA block (Hartzell and Son, Concord, USA) (Figure 7) or specifically designed micro-apical placement (MAP) system (Dentsply Maillefer, Ballaigues, Switzerland) (Figure 8). The adequacy of the preparation and elimination of root-filling materials from the cavity can be confirmed through use of an operating microscope and micro-surgical mirror. A radiograph should be taken post-obturation, prior to suturing, to ensure adequate filling of the root-end cavity (Figure 9).

Figure 7. (a, b) Obturation of the root-end cavity using an MTA block, Lee carver and MTA plugger.
Figure 8. Dentsply MAP MTA Gun system.
Figure 9. Peri-apical radiographs of SRCReT. (a) Pre-operative; (b) post-operative; and (c) at follow-up, revealing bony healing.

Regenerative procedures

Multiple materials have been advocated for guided bone regeneration (GBR) that include: alloplastic materials (calcium sulphate, Bioglass and non-resorbable membranes (ePTFE)), xenograft materials (denatured bovine bone and porcine-derived resorbable collagenous membrane) and allograft materials (donor human bone and collagen membranes). GBR has not been demonstrated to influence longer-term outcomes within small lesions/osteotomy sites and cannot be justified for routine SRCReT.56,57 In large lesions, or those where bilateral labial and palatal cortical plate perforation has occurred, the healed lesion often contains fibrous tissue that may confuse future radiographic assessment for healing. For lesions extending over 10mm in diameter58 the use of a bovine bone scaffold (eg Bio-Oss, Geistlich, Wolhusen, Switzerland, or Cerabone, Botiss Biomaterials GmbH, Berlin, Germany), mixed with blood from the wound site and loosely packed into the cavity space and covered by a porcine-derived resorbable membrane (eg Bio-Gide, Geistlich, Wolhusen, Switzerland, or Jason Membrane, Botiss Biomaterials GmbH, Berlin, Germany) has been associated with high success rates (Figure 10).59 Within through and through lesions, membranes may be employed on both the palatal and buccal aspects to sandwich the xenograft bone within the cavity. It should be noted that a horizonal periosteal relieving incision may be required to ensure tension-free repositioning of the flap.

Figure 10. Grafting of an apical defect with perforation of both the palatal and buccal plates. (a) A membrane (Bio-Gide, Geitschlich) is placed onto the palatal wall of the defect, (b) with filling of the cavity space with bovine particulate bone (Bio-Oss, Geitschlich) and (c) placement of a second membrane layer over the buccal/labial cavity defect.

Wound closure

Absorbable (Polycaprone, Polygalactin), non-absorbable single-strand (polypropylene, polyamide) as well as braided threads (silk) have been advocated for dental microsurgical procedures.60 The number and type of sutures required should be governed by flap design. In general, interrupted sutures are normally placed 2 mm apart, though this will depend on suture size. A sufficient number of sutures need to be placed to approximate the edges of all of the incisions. The original concept by Harrison61 of closing relieving incisors with a single interrupted suture has now been superseded by approaches that aim to reduce scarring and recession by using multiple sutures.14 These sutures should be orientated obliquely from the flap to the mucosa to reduce tissue contraction. Fine, non-absorbable sutures (5.0 or 6.0), as employed within plastic surgery,62 provide optimal mucosal healing when placed using a single interrupted suture technique (Figure 11),60 although other techniques are also appropriate. Following closure, the wound should then be compressed, to eliminate excess blood and help produce close adaptation of the flap to the bone, for 5 minutes with a sterile surgical gauze, soaked with saline.

Figure 11. Closure of the flap using 5/0 monofilament non-absorbable Ethicon sutures.

Post-operative management

Pain management

NSAIDs and non-opioids are effective in managing pain following dental surgery.6365 Providing the patient with ibuprofen (400 mg, three times daily) and paracetamol (1000 mg, four times daily), should provide effective post-operative pain relief.

Management of complications

Although early-presenting complications with SRCReT procedures are rare, the clinician should be aware of problems such as post-operative bleeding, swelling and flap breakdown. The management of swelling is best managed with NSAIDs66 and steroids3 or via adjuncts such as cold compresses (20 minutes on 20 minutes off for no more than 4 hours).67 Tooth brushing should be continued as normal but the patient advised to avoid brushing the teeth associated with the surgical site. For plaque control, patients should use a mouthwash containing chlorhexidine gluconate,68,69 although not until 30-minutes after tooth brushing to prevent any neutralizing effect from sodium lauryl sulphate.70 Patients should avoid vigorous rinsing, which could undermine the flap, instead patients should be advised to allow the mouthwash to bathe the area for 1-minute, twice daily until sutures are removed.

Suture removal

There has been no universal agreement on the optimum time to remove sutures. Research into the healing of incisional wounds using an animal model demonstrated epithelial bridging at 48–72 hours, which some authors have used to support removal of sutures within this early time frame.61 However, observations from clinical outcomes using microsurgical techniques have supported the benefits of delaying suture removal by up to 10 days.14 The time to suture removal should balance the benefits of mechanical stabilization of the wound provided by sutures against the inflammation that occurs around sutures, which can impede healing.71 The authors recommend removal of sutures between 7–10 days. Following suture removal, surgical soft-bristled brushes can be provided to facilitate brushing of the surgical site for a further 14 days, reducing the risk of gingival trauma and recession.72

Review

The outcome for the majority of cases may be determined at one-year post-operative review.6 Strict assessment criteria are available4 and are determined as follows: success (absence of clinical signs/symptoms + radiographic resolution of peri-apical lesion; uncertain (absence of clinical signs/symptoms but with incomplete radiographic resolution of peri-apical lesion) and failure (signs/symptoms + no resolution or expansion of peri-apical lesion). Indication of treatment failure may result from both patient reported factors (such as pain and swelling or discharge from the surgical site), clinical signs of failure (such as pain initiated by examination of the surgical site, erythema, the presence of a sinus tract or swelling) and radiographic examination (continued presence or increased size of peri-apical area). Aiming to capture the same film angulation, as taken in the pre-operative view, reduces the risk of false conclusions regarding the reduction or increase of the size of the peri-apical radiolucency. Treatment success may be determined if there is an absence of symptoms or signs and infill of the radiographic bony lesion. An uncertain outcome may be an absence of signs or symptoms and a radiographic bony defect that decreases in size but fails to completely resolve.

Summary

Evaluating the approaches adopted for surgical root canal retreatment within the endodontic literature facilitates decision-making when constructing a surgical protocol for achieving optimal treatment outcome. By adopting best-practice techniques (as derived from the discipline's current evidence base), high success rates should be achieved with endodontic surgery.