Non-surgical Root Canal Treatment Case III:
Maxillary Anterior/Difficult case (Calcified Coronal ½ Canal System)
Andrew L. Shur
“I would like to lighten the shade of my tooth so it matches with the rest of my teeth.”
The patient (Pt) was a 58-year-old Caucasian female. Vital signs were as follows: blood pressure (BP) 120/78 mmHg with a pulse of 60 beats per minute (BPM). The Pt was at the time under medical/psychiatric care for mild depression. She reported an allergy to codeine. She was taking the following medications: Celexa®, Lunesta™, Wellbutrin SR®, calcium, vitamin D, and Synthroid®.
The Pt was considered American Society of Anesthesiologists Physical Status Scale (ASA) Class II.
The Pt does not recall any history (Hx) of traumatic events affecting tooth #11 and denies previous orthodontic therapy in the recent years. She denies any discomfort associated with the tooth; however, she has noticed the crown of tooth #11 becoming progressively darker over time. The Pt consulted her general dentist who subsequently made the referral for an evaluation for possible endodontic therapy and internal bleaching of tooth #11.
Extra-oral Examination (EOE)
The EOE revealed no abnormal findings.
Intra-oral Examination (IOE)
The perioral and IOE did not yield any abnormal findings. All tissue appeared satisfactory in color and texture. There was no gingival recession present. Periodontal probings measured between 1–3 mm circumferentially around tooth #11. There were no caries, cracks, restorations, or resorptive defects associated with tooth #11. The crown of tooth #11 was much darker than the adjacent teeth as well as the contralateral canine tooth (Figure 9.6).
WNL: Within normal limits; –: No pain upon biting
Tooth #11 was an unrestored tooth with an intact crown. The bone height appeared WNL, as well as the width of the periodontal ligament (PDL). There were no lateral or apical radiographic findings associated with tooth #11. The canal appeared calcified in the coronal half of the crown and root.
Pulp Necrosis, tooth #11
(Diagnosis is purely based on a “no cold” response to thermal testing; however, this is to be expected due to the amount of coronal canal calcification)
Normal Apical Tissue, tooth #11
Refer Pt back to general dentist for external bleaching and/or possible veneer. Based on the radiographic, clinical, and cone beam-computed tomography (CBCT) examination, no endodontic therapy was recommended at that time.
Endodontic therapy on tooth #11 and internal bleaching
Veneer or palatal and incisal resin access restoration if endodontic therapy was to be initiated.
First visit (Day 1): A periapical (PA) film was taken of tooth #11 (Figure 9.1). EOE and IOE were performed. The radiographic and clinical examinations yielded no abnormal findings. Since the Pt was asymptomatic and Pt’s only issue was the discoloration, no endodontic therapy was recommended. It was recommended that she return to her general dentist for potential external bleaching with the consideration of a cosmetic veneer for the crown discoloration. The Pt understood the recommended treatment (Tx) and planned to consult with her general dentist regarding external bleaching and cosmetic restorative options.
Second visit (2 years, Day 1): The Pt re-presented two years later. Pt was still asymptomatic and a new PA film showed a similar calcified coronal half canal system as previously noted (Figure 9.2). A limited field of view CBCT, Veraviewepocs® 3De, (J. Morita, Kyoto, Japan), was taken which confirmed coronal half canal calcification in the coronal, axial, and sagittal planes (Figures 9.3, 9.4, and 9.5). She reported she consulted with her general dentist regarding the external bleaching and cosmetic options. The general dentist recommended internal bleaching due to the deep discoloration present within the crown. The general dentist did not feel she could obtain an adequate aesthetic result with external bleaching, and was hesitant to prepare an intact crown for a cosmetic veneer. The potential risks of endodontic therapy on tooth #11 due to the calcified coronal 1/2 canal system were explained to the Pt. She was made aware that perforation was a potential risk; however, I explained that I would not become overly aggressive searching for the calcified canal since she was asymptomatic and the radiographic and CBCT examination appeared WNL. The Pt signed consent for endodontic therapy and internal bleaching, and Tx was scheduled.
Third visit (Day 26): The Pt presented for Tx. BP and pulse were taken and recorded. Anesthesia was achieved with 2 x 1.8 cc lidocaine (lido) and 1:100,000 epinephrine (epi) administered via local infiltration. Tooth #11 was isolated with a rubber dam (RD). A surgical operating microscope was utilized and a palatal endodontic access towards the incisal was prepared in tooth #11. Clinically, the canal system was calcified in the crown and coronal root structure, as evidenced from the radiographic and CBCT examination. Using long shank small burs, Ethylenediaminetetraacetic acid (EDTA), sodium hypochlorite (NaOCl), and the surgical operating microscope (SOM), I was able to discern the calcified pulp canal space as a dark ring of dentin centrally placed within the root. Carefully following the dark dentin with the long shank burs and ultrasonic instruments, the pulp canal was eventually located. No excess dentin appeared to be removed from the mid root or peri-cervical region of the tooth, and the root was not perforated in the process. The pulp tissue in the root appeared necrotic as it was not the typical pink healthy tissue in a “normal tooth.” The root canal system was shaped with a combination of rotary instruments and stainless steel hand files. The canal was irrigated with 5.25% NaOCl and 17% EDTA. The irritants were activated and the canal was dried with micro-suction and paper points. Patency was checked with a size #8 hand file. The canal was obturated with vertical compaction of warm gutta-percha (GP) with AH Plus® Root Canal Sealer (Dentsply Sirona, Konstanz, Germany) to within a few millimeters of the cementoenamel junction (CEJ). Cavit™ (3M, Two Harbors, MN, USA) was placed over the GP up to the CEJ to act as a barrier for the bleach. It was, and remains, the opinion of the clinician that Cavit™ appears to serve as well as glass ionomer or resin as a protective orifice seal for the purpose of internal bleaching. Sodium perborate and superoxyl were mixed and carefully placed within the access cavity. The access was sealed with Cavit™ as a temporary restoration. All postoperative instructions were reviewed and the Pt was booked in for a “bleach check” appointment.
Fourth visit (1-week follow-up): The Pt presented for a bleach check. The tooth was asymptomatic. Although the color had improved since the initial visit (Figures 9.6, 9.7 and 9.8), the crown was still darker and the Pt desired to continue bleaching. Tooth #11 was re-isolated with a RD. No anesthesia was administered. The Cavit™ was removed and the access cavity was irrigated with sterile water. A fresh mixture of sodium perborate and superoxyl was placed into the access and sealed with CavitTM. The Pt scheduled for another “bleach check” appointment.
Fifth visit (2-week follow-up): The Pt presented for another bleach check. The tooth was still asymptomatic. Although the color had improved since the first bleach application, the crown was still slightly darker and the Pt desired to continue bleaching. Tooth #11 was re-isolated with a RD. No anesthesia was administered. The Cavit™ was removed and the access cavity was irrigated with sterile water. A fresh mixture of sodium perborate and superoxyl was placed into the access and sealed with CavitTM. The Pt scheduled for another “bleach check” appointment.
Sixth visit (4-week follow-up): The Pt presented and was happy with the color of tooth #11. The tooth was re-isolated with a RD. No anesthesia was administered. The CavitTM was removed and the access was flushed with sterile water. The access was restored with bonded composite resin and contoured smooth. The occlusion was checked and adjusted as necessary. A postoperative PA radiograph was taken (Figure 9.9). The Pt was placed on a standard recall.
A one-year recall PA radiograph was e-mailed from the referring dentist for review (Figure 9.10). The Pt was not seen in the office for a recall examination at that time.
Seventh visit (4-year follow-up): The Pt presented for a recall examination four years after the Tx was complete. She was asymptomatic and the PA radiograph of tooth #11 appeared WNL (Figure 9.11). The surrounding periodontal tissues also appeared WNL. The color of tooth #11 had remained stable within the four-year period (Figure 9.12). The Pt was placed on another one-year recall.