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Scott A. Norton, DMD, MSD

Scott A. Norton, DMD, MSD

Focus on family, patients, friends, growth, and community What can you tell us about your background? For as long as I can remember, I wanted to make people smile. I always loved getting the class laughing in grade school. Looking back, I am sure...

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Dr. Fleur A. Blethen

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Empathy, tenacity, and perseverance are keys to this clinician’s flourishing practice  What can you tell us about your background? I was born and raised in Seattle, Washington, and lived there until I was 13 years old. My family relocated...

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Dr. Ernest Reeh, Practice Profile

Dr. Ernest Reeh, Practice Profile

Focus on patients, family, academics, and endodontics What can you tell us about your background? I have a bachelor’s degree in chemistry with a minor in business. I was accepted off of the alternate list for dental school and then attained...

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Clinical Articles

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GuttaCore® system: a step forward in the evolution of endodontics

GuttaCore® system: a step forward in the evolution of endodontics

Dr. Andrei Zoryan dispels some of the common myths surrounding carrier-based obturation Carrier-based gutta percha Carrier-based obturation (such as Thermafil®, GT® obturator, ProTaper® obturator [Dentsply Tulsa Dental Specialties]) is one...

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Endodontic retreatment of a lower right first molar with WaveOne®

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Dr. David C. Baker uses a technique that facilitates quick and predictable results Patient history The patient is a 34-year-old female who was referred by a local colleague. She had broken her lower right first molar and complained of some general...

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The Laschal FXP set incorporates transferred oscillation technology

Background There are other ultrasonic devices on the market that depend upon direct contact with a separated file to loosen and remove. However, it is absolutely impossible to restrict the contact of the tip to the file remnant itself. The vibrations...

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Practice Management

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Superior customer service

Superior customer service

Dr. Roger Levin presents the 10 top ways to help create a perfect dental team With the changes brought on by the economy, top companies are bringing in the best resources they can find to evaluate where their organizations stand. They want to know...

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Office Matters: Hard-piped filtered water system vs. self-contained bottled water system

John Bednar helps avert problems coming down the pipe If your office currently has a hard-piped filtered water system, now is a good time to consider if and when you should change to a self-contained bottled water system. A hard-piped filtered water...

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Secrets to financial and personal freedom for endodontists

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In part 1 of his series, Dr. Ace Goerig offers the first steps to becoming debt-free I was presenting at a recent AAE national meeting with over 200 endodontists in the room, and I asked the question, “How many of you are completely debt-free?” ...

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Dr. Navid Saberi presents an uncommon case of a two-rooted mandibular canine



It is well established that bacteria are essential for the development of pulpal and periradicular diseases (Kakehashi et al, 1965; Möller et al, 1981), and the presence of bacteria in the root canal space or periapical tissue will undermine the success of endodontic treatment (Sjögren et al, 1997; Byström et al, 1987). Therefore, for a successful treatment, all the canals should be identified, thoroughly disinfected, and rendered bacteria-free prior to obturation.

A sound knowledge of root canal anatomy and morphology, appropriate radiographic assessment, and the use of magnification will aid the clinician in identifying the anatomical variations in teeth. Mandibular canines often present as single-rooted teeth with a single canal. However, variations in the root numbers and root canal configurations have been reported (Taylor, 1886; Vawter, 1886; Vertucci, 1984; Pécora et al, 1993). The case that is discussed here is somewhat unique, as the presence of a two-rooted mandibular canine with an apical third bifurcation does not seem to have been reported previously.  

Case report
A healthy 30-year-old man was referred to the practice for the assessment and possible root treatment of the mandibular rightScreen_shot_2012-01-06_at_2.41.02_PM canine and mandibular right lateral incisor. These teeth were associated with a chronic buccal sinus tract, and the patient had been reporting a bad taste in his mouth. There was no complaint of pain. A diagnostic radiograph was available (Figure 1).
In the past, the patient reported intermittent bouts of swelling around the roots of the mandibular right canine and right lateral incisor (teeth Nos. 42 and 43). There was no discomfort or pain, but tenderness had been reported, especially on tooth-to-tooth contact. Thermal changes did not trigger the pain. There was no sleep disturbance, and the tenderness and slight discomfort were well localized. Extraoral examination revealed no facial asymmetry or lymphadenopathy.

Intraorally, there was a draining sinus tract on the attached gingivae between the lower right canine and right lateral incisor. There was also a buccal swelling associated with these teeth. The color of the mucosa was, however, normal. The swelling was fluctuant. There was no lingual swelling.

There were no periodontal pockets greater than 3 mm, which would suggest periodontal involvement or fracture, but there was some delayed bleeding on probing. Teeth Nos. 42 and 43 were unrestored. However, both tested negatively to the cold test and were tender to percussion (TTP) vertically, but not horizontally. No cracks could be detected.

There were no occlusal interferences, and the occlusion was canine guided. The diagnostic radiograph revealed the presence of apical radiolucencies associated with the apices of teeth Nos. 42 and 43. The radiolucencies were well corticated, suggesting the chronic nature of events. Tooth No. 43 was associated with two shorter-than-normal roots. The diagnosis of chronic apical periodontitis was made. Without histological examination, however, we were unable to confirm if the lesion was granulomatous or cystic in nature (Torabinejad and Walton, 2002).

Although the patient could not remember any traumatic facial or dentoalveolar injuries in the past, impact trauma seems more likely to be the cause of the necrosis of teeth Nos. 42 and 43. Trauma could also be related to occlusal factors. However, no parafunctional habits were detected in this case.

Trauma due to orthodontic tooth movement was ruled out, as the patient had never had any orthodontic treatment. Trauma as a result of periodontal treatment was also ruled out due to the lack of deep periodontal pockets.
Anachoresis could also be considered to be the reason behind the bacterial infection of the nonvital and traumatized teeth and was not ruled out (Torabinejad and Walton, 2002).

Based on the information obtained, it was decided to carry out a multi-visit orthograde root canal treatment on teeth Nos. 42 and 43. Treating tooth No. 43 would be challenging due to its root morphology and the location of its bifurcation.

After local anesthetic administration and rubber dam placement, the access cavity on tooth No. 43 was prepared using an Endo Access™ Bur size 2 (Dentsply/Maillefer), and a straight-line access to the pulp chamber was gained. Drainage was spontaneous when the tooth was opened. Pus was irrigated with 1% sodium hypochlorite, and the pulp chamber was filled with EDTA  paste. The pulp chamber was then shaped with a Gates Glidden drill size 4. Next, C+ files (Dentsply/Maillefer) sizes 10 and 15 were used to negotiate and scout the canals at estimated 3 mm short of the radiographic apex. An electronic apex locator was used to estimate the working length (WL), but the reading could not be relied upon at this stage. Subsequently, a WL radiograph was taken with the files inside the canals. Following this, a Gates Glidden drill size 4 was placed inside one canal by hand at 15 mm in order to identify the exact position of the bifurcation.

The WL radiograph (Figure 2) showed both files to be in one (buccal) canal. However, the second radiograph (Figure 3) helped in the estimation of the position of the bifurcation, which was judged to be at 10 mm (from the reference point).
With the use of the endodontic microscope, the access cavity was refined with a Diamendo® Bur size 2 (Dentsply/Maillefer), and straight-line access to the lingual canal was prepared.

The pulp chamber and the coronal third of the canal were shaped again with a Gates Glidden drill size 4, especially towards the lingual side of the coronal and mid-third of the canal up to the bifurcation. The WL was then confirmed with an electronic apex locator. Another WL radiograph was taken (Figure 4).

Both canals were then shaped to the full WL with C+ files 10 and 15 and S1/S2/F1/F2 ProTapers® (Dentsply/Maillefer). The canals were irrigated with 1% sodium hypochlorite and recapitulated with size 10 C+ file between the files.
Canals were obturated at the third visit using F2 ProTaper® (Dentsply/Maillefer) gutta-percha master points, and AH Plus® cement (Dentsply/Maillefer) using the cold lateral compaction technique. The lingual canal was obturated first, and the excess GP and cement removed from the mid- and coronal third of the canal, which facilitated straight-line access for obturation of the buccal canal and the rest of the canal system coronal to the bifurcation.

The post-obturation radiograph showed adequate vertical and lateral compaction of the gutta percha. The presence of a sealer puff was also evident at the apex of the buccal canal (Figure 5). Tooth No. 43 was coronally restored with light-cured resin composite.

Tooth No. 42 was treated in a similar fashion but in two visits. The master apical file for tooth No. 42 was a ProTaper® F3, and it was obturated and restored using the same technique. The postoperative radiograph also showed adequate vertical and lateral compaction of gutta percha. In this radiograph, the sealer puff from the buccal root of tooth No. 43 was detached from the apex of the tooth (Figure 6). The recall radiograph (12 months) showed almost complete healing of the lesion (Figure 7).         
Copious irrigation with 1% sodium hypochlorite and recapitulation using a size 10 C+ file together with the use of EDTA paste with every file and non-setting calcium hydroxide (Hypo-Cal™, Ellman®) as an inter-visit medicament, all were part of the treatment procedure. The canals were obturated when they were clinically confirmed to be dry.  

Discussion
Mandibular canines normally present as single-rooted teeth with one canal. However, variations in the root numbers and canals have been reported (Taylor, 1886; Vawter, 1886; Vertucci, 1984; Pécora et al, 1993).

Screen_shot_2012-01-06_at_2.41.47_PM

In a retrospective radiographic study of 400 mandibular canines, Kaffe et al (1985) reported that 13.75% of these teeth presented with two canals. This calculation was carried out after viewing two radiographs of each case, taken from different angles, and combining the figures.

Vertucci (1984) examined 100 extracted mandibular canines and observed only 6 teeth with type IV canal configuration (two separate and distinct canals from the pulp chamber to the apex). However, Pécora et al’s (1993) observations concluded that only 1.2% of mandibular canines have two canals. Torabinejad and Walton (2002), on the other hand, stated that this figure is closer to 10%.

Screen_shot_2012-01-06_at_2.42.34_PM

The presence of two separate roots with two separate canals has also been reported. Pécora et al (1993) studied 830 extracted mandibular canines and found 1.7% of the teeth to have two roots. Ouellet (1995) concluded that up to 5% of mandibular canines could have two roots.  In one case report, D’Arcangelo et al (2001) reported that 15% of mandibular canines may have two canals, and a smaller number may have two roots. Moreover, in a case presentation, the occurrence of a two-rooted mandibular canine with three canals was reported (Heling et al, 1995). In fact, these variations in prevalence may indicate the influence of geographic and ethnic factors in tooth anatomy. However, in none of the aforementioned case reports does the bifurcation seem to be located at the apical third of the root.

The other factor that is of relevance in this case is the presence of apical pathosis in virgin teeth. While the etiology of apical periodontitis is bacteria related (Kakehashi, 1965; Möller, 1981), the initial irritation and inflammation of the pulp can be caused by mechanical factors (Torabinejad and Walton, 2002). These include impact trauma, occlusal trauma, deep periodontal debridement, and orthodontic movement. The inflammation caused by these irritants can lead to the loss of tooth vitality, which in turn allows the infiltration of bacteria in the root canal system through open tubules, microcracks, or by the process of anachoresis (Torabinejad and Walton, 2002). A thorough history and examination will aid the clinician in making the correct diagnosis and is always carried out prior to the commencement of root canal treatment.   

Conclusion
A variation in the internal configuration of root canals can render treatment procedures difficult. This variation can lead to unsuccessful root canal treatment due to the presence of unidentified and/or untreated canals. However, accurate radiographic examination of each case and knowledge of root canal anatomy together with the use of magnification can help in identification and preparation of the root canals of these teeth.  

Acknowledgements
The author would like to thank Dr. Ruth Newcombe and Dr. Priya Kalsi for providing radiographs 1 and 7.

Bio
Navid Saberi, BDS, MFDSRCSEd, MSc, is a salaried general dental practitioner for NHS Borders. He is also honorary secretary of Scottish Endodontic Study Group. For more information about that study club, please visit www.sesg.org.uk.

References
Byström A, Happonen RP, Sjögren U, et al (1987) Healing of periapical lesions of pulpless teeth after endodontic treatment with controlled asepsis. Endod Dent Traumatol 3:58-65.

D’Arcangelo C, Varvara G, De Fazio P (2001) Root canal treatment in mandibular canines with two roots: a report of two cases. Int Endod J 34:331-334.

Heling I, Gottlieb-Dadon I, Chandler NP (1995) Mandibular canine with two roots and three root canals. Endod Dent Traumatol 11:301-302.

Kaffe I, Kaufman A, Littner MM, et al (1985) Radiographic study of the root canal system of mandibular anterior teeth. Int Endod J 18:253-259.

Kakehashi S, Stanley H, Fitzgerald R (1965) The effects of surgical exposures of dental pulps in germ-free and conventional laboratory rats. Oral Surg Oral Med 20:340-349.

Möller ÅJR, Fabricius L, Dahlén G, et al (1981) Influence on periapical tissues of indigenous oral bacteria and necrotic pulp tissue in monkeys. Scand J Dent Res 89:475-484.

Ouellet R (1995) Mandibular permanent cuspids with two roots. J Can Dent Assoc 61:159-161.

Pécora JD, Sousa Neto MD, Saquy PC (1993) Internal anatomy, direction and number of roots and size of human mandibular canines. Brazilian Dental Journal 4:53-57.

Sjögren U, Figdor D, Persson S, et al (1997) Influence of infection at the time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis. Int Endod J 30:297-306.

Taylor D (1886) Two distinct roots in inferior cuspid. Dental Cosmos 28:128.

Torabinejad M, Walton R E (2002) Endodontics principles and practice, 4th ed. St. Louis: Saunders.

Vawter G A (1886) Dental anomalies. Dental Cosmos 28:64.

Vertucci F J (1984) Root canal anatomy of the human permanent teeth. Oral Surg Oral Med Oral Pathol 58:589-599.

Victoriano FR, Bernardes RA, Baldi JV, et al (2009) Bilateral mandibular canines with two roots and two separate canals—case report. Brazilian Dental Journal 20:84-86.

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