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.
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.
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.
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).
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: email@example.com.
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