Non-surgical Root Canal Treatment Case VI:
Mandibular Premolar / Difficult Anatomy (three canals)
Savita Singh and Gayatri Vohra
Chief Complaint
“I have been having discomfort on and off for past few days. Especially, cold has been bothering.”
Medical History
The patient (Pt) was a 64-year-old male. He had high blood pressure (BP), which was under control, and took Arenol, 50 mg daily for this condition. Pt had allergy to penicillin. No significant findings were noted as a result of complete review of systems. No contraindications to dental treatment were identified.
The Pt was classified as American Society of Anesthesiologists Physical Scale Status (ASA) Class II.
Dental History
Tooth #21 had a cervical composite restoration. The Pt had been having discomfort for the previous month, mild to begin with but later when he drank cold water or went for a walk, he could feel cold sensitivity on the tooth. It bothered him and was painful. There was no discomfort with hot beverage. Tooth #20 also had a cervical composite restoration.
Clinical Examination (Diagnostic Procedures)
Examinations
Extra-Oral Examination (EOE)
There was no swelling present and no tenderness on palpation, especially in the area around tooth #21.
Intra-Oral Examination (IOE)
Examination showed that probing depth of tooth #21 was within normal limits such as MB 3 mm, B 2 mm, DB 3 mm, ML 3 mm, L 2 mm, DL 3 mm.
Diagnostic Tests
| Tooth | #22 | #21 | #20 |
| Percussion | – | + | – |
| Palpation | – | – | – |
| Cold | + | ++ | + |
| Tooth Slooth | – | – | – |
++: Exaggerated response to cold; +: Response to percussion and normal response to cold; -: No response to percussion, palpation, and tooth slooth
Radiographic Findings
Two radiographs were taken, straight (Figure 12.1) and mesial-angled (Figure 12.1). They showed tooth #21 and tooth #20 had cervical composite restoration; the periapical areas seemed to be normal. The root had unusual anatomy; it was very wide and showed trifurcation of the canal system.
Figure 12.1 Preoperative radiographs of tooth #21, showing Class 5 restoration and wide root tri-furcating at coronal-middle third of root. A: Straight view; B: Mesial angled view.
Pretreatment Diagnosis
Pulpal
Symptomatic Irreversible Pulpitis, tooth #21
Apical
Symptomatic Apical Periodontitis, tooth #21
Treatment Plan
Recommended
Emergency:None
Definitive:Non-surgical root canal treatment (NSRCT)
Alternative
Extraction or no treatment
Restorative
Crown
Prognosis
| Favorable | Questionable | Unfavorable |
| X |
But will depend upon successfully finding and obturating all the canals
Clinical Procedures: Treatment Record
First Visit (Day 1): Pt’s BP was 130/76 mmHg. Anesthesia was achieved with 2% lidocaine (lido) with 1:100,000 epinephrine (epi) (1 carpule), left Inferior alveolar nerve block (IANB), 1 carpule of 2% lido with 1:100,000 epi infiltration around the tooth. The treatment was performed using a Zeiss microscope (OPMI-Pico, Carl Zeiss-USA, Dublin, CA, USA). Tooth #21 was clamped and a rubber dam (RD) placed. Access was made using No. #4 round carbide bur. The tooth was dis-occluded and the access was widened with a long-fissure bur. The shape of the access was oval but made little wider mesial–distally (MD) due to an unusual trifurcated anatomy of the root. On entry into the pulp chamber, one main canal orifice was found which split into three different canal orifices at the coronal–mid-root level. Mesio-buccal (MB), Disto-buccal (DB) and Lingual (L) canals were identified with magnification and illumination. Gates Glidden drills #3, #2, and, #1 with a brushing motion were used in a crown-down fashion to enlarge the main orifice to the level of the trifurcation to obtain straight line access to all the three canals. MB, DB and L canals were located, and their orifices were widened using S1 and S2 ProTaper® Universal files (Dentsply Sirona, Ballaigues, Switzerland). Full-strength sodium hypochlorite (6 % NaOCl) was used for canal irrigation. Canals were dried with paper points (PPs). A size #10 K-file (ReadySteel® K-File, Dentsply Sirona, Ballaigues, Switzerland) was pre-curved and used to determine the working length of the canals, together with an electric apex locator (Root ZX®II, J. Morita, Kyoto, Japan). All canals measured 21 mm in length. Biomechanical preparation was started. Canals were hand-instrumented to working length with size #15 K-file (ReadySteel® K-File, Dentsply Sirona, Ballaigues, Switzerland). Canals were irrigated with 6 % NaOCl and then dried with PPs. After drying the canals, Calcium hydroxide (Ca(OH)2 MultiCal™,Watertown, MA, USA) was placed inside the canal, cotton pellet (CP) and Cavit™ (3M, Two Harbors, MN, USA) and Fuji IX GP® (GC America Inc., Alsip, IL, USA) was placed for temporalization. Pt was advised to take 200 mg to 400 mg of Ibuprofen every 4–6 hours as needed for any post-operative (PO) discomfort and inflammation.
Second Visit (3 week): Pt was doing well, with no discomfort or changes in medical history. BP was recorded at 128/72 mmHg. 2% lido with 1:100,000 epi (1 carpule) as left IANB and 1 carpule of 2% lido with 1: 100,000 epi infiltration around the tooth were administered. A RD was placed and temporary cement was removed using a round bur. Irrigation was done using 6% NaOCl, and biomechanical instrumentation was completed in all three canals. All the canals were enlarged to size #25/ .04 taper of ProFile® (Dentsply Sirona, Ballaigues, Switzerland), the canals were dried using PPs, and a periapical (PA) radiograph was taken with gutta-percha (GP) in DB and L canal. First, the DB and L canals were obturated and then the third canal was obturated (Figure 12.2). System-BTM (Kerr, Orange, CA, USA) and ObturaTM system (Spartan Obtura, Algonquin, IL, USA) was used for obturation by continuous-wave technique. The GP in each canal was seared 4–5 mm from the apex and then backfilled with ObturaTM system. After obturating the DB and L canal, a GP cone was placed in MB canal and a PA radiograph was taken (Figure 12.3). The MB canal was then obturated (Figure 12.4). Size #25/ .04 taper Lexicon® GP point (Dentsply Sirona, Johnson City, TN, USA) and Pulp Canal Sealer™ EWT (Kerr Endodontic) were used. CP, Cavit™, and Fuji IX GP® was placed. Post-obturation radiographs were taken (Figure 12.5, 12.5). Post-operative instructions (POI) were given. The Pt was instructed to take over-the-counter ibuprofen 200 mg to 400 mg every 4–6 hours as needed for post-operative discomfort. The Pt was advised to get a crown.
Working length, apical size, and obturation technique
| Canal | Working Length | Apical Size, Taper | Obturation Materials and Techniques |
| MB | 21.0 mm | 25, .04 | Pulp Canal Sealer™ EWT, Continuous wave |
| L | 21.0 mm | 25, .04 | Pulp Canal Sealer™ EWT, Continuous wave |
| DB | 21.0 mm | 25, .04 | Pulp Canal Sealer™ EWT, Continuous wave |
Figure 12.2 Down-packed and backfilled DB and L canals and checking the MB canal.
Figure 12.3 Checking the MB canal.
Figure 12.4 The MB canal obturated.
Figure 12.5 A: Postobturation radiograph showing three canals with three different exit portals; B: Postobturation radiograph showing three exit portals.
If cone beam-computed tomography (CBCT) had been available, it would have been beneficial to give a three-dimensional view of the tooth.
Post-Treatment Evaluation
There were no post-treatment evaluations as Pt moved out of the country.
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