Oral Health Group

A Complicated Endodontic Retreatment Using Cone Beam Computed Tomography Scanning as a Diagnostic Aid: A Case Report

May 1, 2014
by Garry Bey, DDS

The primary goal of endodontic therapy is to create an environment that promotes and maintains the roots of a tooth in a healthy periodontium. This allows the tooth to be properly restored and returned to function. The goals of both biological health and mechanical function are paramount in evaluating the success of a tooth that has undergone endodontic treatment. A key factor to successful endodontics is proper diagnosis and treatment planning. Among the many diagnostic tools available to clinicians, perhaps the most technologically advanced is cone beam computed tomography (CBCT).

Traditionally, periapical radiographs have been, and are still used, to diagnose apical periodontitis. Successful treatment outcome is determined when symptoms and periapical radiolucency are absent after treatment.1 Periapical radiographic images correspond to a two- dimensional aspect of a three-dimensional structure.2 Periapical lesions confined within the cancellous bone are usually not detected.2-7 A lesion of a certain size can be detected in a region covered by a thin cortex, whereas the same lesion size cannot be detected in a region covered by a thicker cortex.8


It has been reported that CBCT scans detected periapical lesions in many cases where periapical radiolucency was absent in the periapical radiograph.9-13 This case report presents the diagnosis and retreatment of a maxillary second molar.

A 73-year-old man presented to private endodontic practice with a complaint of spontaneous pain that was intermittent. Two preoperative intraoral digital radiographs (Dexis, Alpharetta, GA) revealed a periapical radiolucent area that appeared to be emanating from the distobuccal root of the left maxillary first molar (#26, Fig. 1). The left maxillary second molar (#27) presented with a previous history of root canal therapy completed 13 years ago.  The mesiobuccal and distobuccal roots appeared to be filled short, but showed no evidence of periapical pathology.

FIGURES: 1A & B. Preoperative periapical radiographs of maxillary left first and maxillary left second molars. The distobuccal root of the maxillary first molar appears to be the source of the periapical radiolucent lesion.

FIGURE 1A.                                             FIGURE 1B.

Clinical examination revealed tooth #26 was negative to percussion and negative to biting pressure. Tooth #27 was negative to percussion and slightly sensitive to biting pressure. The referring dentist reported an unclear etiology and requested diagnosis and treatment. A CBCT scan of the left maxilla was performed with limited FOV at 76µm (Kodak 9000; Carestream Dental, Atlanta, GA). A careful examination of the left maxillary second molar showed a diffuse periapical radiolucency centered on the mesiobuccal root and extending to the distobuccal root (Fig. 2). A diagnosis of symptomatic apical periodontitis associated with tooth #15 was made. Upon further examination, the palatal root of tooth #27 presented to be within normal limits (Fig. 3). The periapical radiolucent appearance of the distobuccal root of the maxillary first molar on the intraoral digital radiographs was due to the extension of the radiolucency emanating from the mesiobuccal root of tooth #27 (Fig. 4). Endodontic retreatment of the buccal roots of tooth #27 was proposed and the patient provided informed consent. No further endodontic treatment was indicated for either the palatal root of tooth #27 or for tooth #26 at the present time.

FIGURE 2. Sagittal CBCT image demonstrates a diffuse radiolucency centered on the mesiobuccal root of tooth #27, extending to the distobuccal root of tooth #27.

FIGURE 3. Sagittal CBCT image demonstrates the palatal root of tooth #27 to exhibit a normal radiographic appearance.

FIGURE 4. Sagittal CBCT image demonstrates the diffuse radiolucency associated with the mesiobuccal root of tooth #15 extending to the mesiobuccal root of tooth #26.

Appointment 1
Access was made through the crown with a 135 C round diamond bur (SS White) and a Transmetal bur (Dentsply International). The gutta percha from the mesiobuccal and distobuccal canals was removed. The canals were instrumented to a size .06/25 Twisted File (Axis/SybronEndo). Calcium hydroxide (Calasept, JS Dental) was placed as an intracanal medicament. A sterile cotton pellet was placed in the pulp chamber and the access cavity was sealed with Cavit W (3M ESPE). The occlusion was adjusted.

Appointment 2
The temporary seal was removed and the canals were enlarged to a 50 LSX LightSpeed file  (SybronEndo) as their final apical size. A final irrigation using apical negative pressure (EndoVac, SybronEndo, Coppell, Texas) was performed according to the manufacturer’s suggested protocol of sodium hypochlorite 5.25 percent, followed by 17 percent EDTA, followed by 5.25 percent sodium hypochlorite as the final irrigant. The canals were then dried and obturated with warm vertical compaction of gutta percha and AH Plus sealer (Dentsply Maillefer) (Fig. 5). The access cavity was sealed with Cavit W and the patient was referred to his restorative dentist for a posterior composite resin. The patient was asymptomatic at the six-month follow-up (Fig. 6).

FIGURE 5. Postoperative periapical radiograph of nonsurgical root canal retreatment performed on tooth #26.

FIGURE 6. Periapical radiograph taken at 6-month follow-up showing evidence of healing.

Frequently in endodontic practice, patients present with nondescript symptoms that are often intermittent. These conditions can be challenging for both the patient and the clinician, as they can be complex in both diagnosis and treatment planning. Periapical digital radiographs taken in different angulations are an essential part of endodontic treatment, however, they are taken in a buccal-lingual direction and give only two-dimensional information about a three-dimensional object.14 As is evident with this case, the initial periapical radiographs are inconclusive at best. Attempting to diagnose this without the help of CBCT imaging could have led to treatment of the wrong tooth. In addition, once the correct tooth was chosen the treatment planning was not complete. An assessment of the palatal root indicated that it did not require retreatment. This saved the patient and the clinician an unnecessary attempt at post removal and retreatment of the palatal root, which would probably have lessened a favorable prognosis, rather than have increased it.

The anatomical detail and viewing capabilities of CBCT imaging offer a wide range of diagnostic possibilities such as allowing enhanced assessment of periapical pathology, root canal morphology, retreatment cases, root resorption, maxillary sinus involvement and root fractures. Augmenting our diagnostic capabilities with the use of high-resolution cone beam computed tomography has allowed us to treat our patients with more information, therefore, increasing our chances for a better treatment outcome. This case report indicates that clinicians must have as much information as possible during all phases of endodontic diagnosis and treatment. OH

Dr. Garry Bey is in private practice in New York and New Jersey, specializing in endodontics. He graduated from Syracuse University with a B.S. in Biology in 1976. He received his D.D.S. degree from the NYU College of Dentistry in 1979, and completed his endodontic residency training in endodontics at the NYU College of Dentistry in 1982. Dr. Bey lectures both nationally and internationally and has conducted classes with dentists from over 30 countries. He is a member of the American Association of Endodontists, the American Dental Association, the New York State Dental Association, the New Jersey Dental Association and he is the Past President of the Rockland County Dental Society. He can be reached through his e-mail at: rockendo@aol.com.

Oral Health welcomes this original article.


1. Garcia de Paula-Silva F, Wu Min-Kai, Leonardo M, da Silva L, Wesselink P. Accuracy of Periapical Radiography and Cone-Beam Computed Tomography Scans in Diagnosing Apical Periodontitis Using Histopathological Findings as a Gold Standard. Journal of Endodontics
Volume 35, Issue 7, Pages 1009-1012, July 2009.

2. Huumonen S, Ørstavik D. Radiological aspects of apical periodontitis. Endod Topic. 2002;1:3–25

3. Bender IB, Seltzer S. Roentgeno­graphic and direct observation of experimental lesions in bone: I. J Am Dent Assoc. 1961;62:152–160

4. Bender IB. Factors influencing the radiographic appearance of bone lesions. J Endod. 1982;8:161–170

5. van der Stelt PF. Experimentally produced bone lesions. Oral Surg Oral Med Oral Pathol. 1985; 59:306–312

6. Stabholz A, Friedman S, Tamse A. Endodontic failures and re-treatment. In: Cohen S, Burns RC editor. Pathways of the pulp. 6th ed. St Louis, MO: Mosby; 1994;p. 692–693

7. Ricucci D, Bergenholtz G. Bacterial status in root-filled teeth exposed to the oral environment by loss of restoration and fracture or caries — a histobacteriological study of treated cases. Int Endod J. 2003;36:787–802

8. Wu M-K, Dummer PMH, Wesselink PR. Consequences of and strategies to deal with residual post-treatment root canal infection. Int Endod J. 2006;39:343–356

9. Lofthag-Hansen S, Huumonen S, Gröndahl K, et al. Limited cone beam CT and intraoral radiography for the diagnosis of periapical pathology. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007;103:114–119

10. Jorge EG, Tanomaru-Filho M, Gonçalves M, et al. Detection of periapical lesion development by conventional radiography or computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008;106:e56–e61

11. Estrela C, Bueno MR, Leles CR, et al. Accuracy of cone beam computed tomography and panoramic and periapical radiography for detection of apical periodontitis. J Endod. 2008;34:273–279

12. Paula-Silva FWG, Hassan B, Bezerra da Silva LA, Leonardo MR, Wu MK. Outcome of root canal treatment in dogs determined by periapical radiography and cone-beam computed tomography scans. J Endod. 2009;35:723–726

13. Vandenberghe B, Jacobs R, Yang J. Detection of periapical bone loss using digital intraoral and cone beam computed tomography images: an in vitro assessment of bony and/or infrabony defects. Dentomaxillofac Radiol. 2008;37:252–260

14. Patel S, Dawood A, Whaites E, et al. New dimensions in endodontic imaging: part 1. Conventional and alternative radiographic symptoms. Int Endod J 2009;42:447-62

Print this page


Have your say:

Your email address will not be published. Required fields are marked *