Endodontic Management of Mandibular First Molars
with Three Distal Root Canals-A Report of Two Cases
Al-Hawwas Abdullah Yousef1, Al-Dahman Yousef Hamad2, Aldosary Khalid M3, Al-Dakheel Majed D3, Al-Zuhair Hind4 and Al-Jebaly Asma Suliman4
1Endodontist, Head of Endodontic Division, Dental Department, King Abdulaziz University Hospital, King Saud University, Riyadh, Kingdom of Saudi Arabia
2Endodontist, Ministry of Health, Kingdom of Saudi Arabia
3Consultant in Restorative Dentistry, King Saud University Medical City, Riyadh, Kingdom of Saudi Arabia
4General Practitioner, Riyadh, Kingdom of Saudi Arabia
Submission: June 28, 2018; Published: August 28, 2018
*Corresponding author: Yousef Hamad Al-Dahman, Endodontist, Ministry of Health, P. O. Box: 84891, Riyadh 11681, Kingdom of Saudi Arabia, Email: email@example.com
How to cite this article: Al-Hawwas A Y, Al-Dahman Y H, Aldosary K M, Al-Dakheel M D, Al-Zuhair H, et.al. Endodontic Management of Mandibular First Molars
with Three Distal Root Canals-A Report of Two Cases. Adv Dent & Oral Health. 2018; 9(4): 555768. DOI: 10.19080/ADOH.2018.09.555768
The proper knowledge of root canal anatomy of teeth and its variation is necessary for successful endodontic treatment. Permanent mandibular first molars are usually having two mesial canals and one or two distal canals. Moreover, middle mesial canal was present in different case reports in the literature. However, the presence of three distal canals in distal root is rare. This paper describes two case reports of root canal therapy of permanent mandibular molars with three distal root canals.
The knowledge of the anatomy of root canal system and its morphological variations play a significant role in all the steps of endodontic treatment . Therefore, the clinician should have a thorough understanding of the detailed anatomy of the root canal to be able to utilize the most appropriate treatment techniques and protocols and thereby increasing the percentage of success rate .
Generally, mandibular molars have a complex and varying morphology . The mandibular first molars usually have two roots (mesial and distal) which have two mesial and one or two distal canals, respectively .
Rarely, there is an extra canal called middle mesial (MM) in the mesial root with an incidence ranged from 0% to 46% [4-8]. Moreover, middle distal (MD) canal may present in the distal root with an incidence up to 8% . Additionally, cases of mandibular molars with seven and eight root canals have been reported in the literature [10,11]. Other anatomical variations include radix entomolaris, radix paramolaris, C-shaped canal, and taurodontism [12-15].
Different techniques have been used and described in the literature for evaluation of anatomical variations of the first mandibular molar including plastic resin injection , endodontic access and radiographs with files into root canals , retrospective evaluation of radiographs , clearing of
samples with and without ink injection [18,19], sectioning and macroscopic or scanning electron microscopy (SEM) evaluation [20,21], computed tomography (CT) , spiral computed tomography (SCT) , micro-computed tomography (μ-CT) , and cone-beam computed tomography (CBCT) . The present case report describes a successful endodontic management of two cases of mandibular first molar with 3 distal canals.
A 24-year-old Saudi female patient with a noncontributing medical history was referred to endodontic department of Prince Sultan Military Medical City, Riyadh, Saudi Arabia, for root canal treatment of mandibular right first molar (#46). The chief complaint was to complete the root canal treatment which was previously initiated by a general practitioner. Clinical examinations revealed a temporary restoration on tooth #46, in addition to sensitivity on percussion and unremarkable findings with palpation, and normal probing depth with no mobility. Radiographic examination revealed a coronal radio-opaque temporary filling, previously initiated root canal treatment, one metallic object resembling an endodontic file situated in the intracanal space of one of the mesial canals and a periapical radiolucency in both mesial and distal roots (Figure 1a). Based on the clinical and radiographic findings and according to American Association of Endodontics consensus , the tooth was diagnosed as previously initiated root canal treatment with symptomatic apical periodontitis.
Local anesthesia was administered with 2% lidocaine and
1:100000 epinephrine, and treatment was initiated under rubber
dam isolation. The temporary restoration was removed, and
access was gained to the pulp chamber. After endodontic access
preparation, the pulpal floor was inspected under magnification
loupes 5.5x (PrismPro Line Loupes, SurgiTel, MI, USA). Two
separate mesial and two separate distal canals were identified. On
careful examination of distal canals, one additional canal orifice
[Middle Distal (MD)] was identified in the center of the groove and
situated between the distobuccal (DB) and the distolingual (DL)
With the aid of the same magnification loupes, a separated
instrument was confirmed in the middle portion of the MB canal.
Coronal flaring was achieved with size #3 and #4 Gates-Glidden
drills (Dentsply Maillefer, Ballaigues, Switzerland) to establish
straight line access. 5.25% sodium hypochlorite (NaOCl) irrigating
solution was used to irrigate the MB canal and Glyde (Dentsply,
Maillefer, Ballaigues, Switzerland) was used as a canal lubricant.
Unfortunately, the instrument was located beyond a curvature
and attempts failed to remove it, so it was bypassed successfully
starting with a #8 followed by #10 then #15 K-flex files (Kerr
Manufacturing Co., Romulus, MI). Other canals were negotiated
using #15 K-flex files.
Then, the working length was established using Root ZX II
(J. Morita, Tokyo, Japan) electronic apex locator and confirmed
radiographically (Figure 1b & 1c). After finalizing the access
cavity (Figure 1d), the root canals were prepared using K3 Rotary
System (SybronEndo, Orange, CA, USA) to size 30 0.06 taper for
all canals. Copious irrigation with NaOCl 5.25% followed by 17%
ethylenediaminetetraacetic acid (EDTA) was carried out during
the instrumentation phase. After the final flush, root canals
were dried with paper points (Maillefer, Dentsply, Ballaigues,
Switzerland) and obturated with gutta-percha and AH26 sealer
(Dentsply, Maillefer, Switzerland) using cold lateral compaction
technique (Figure 1e). The access cavity was sealed with Fuji
resin‑modified glass ionomer filling material (ChemFil, Dentsply
DeTrey, Germany) (Figure 1f & 1g). Follow-up has been made in
6 months (Figure 1h & 1i). The tooth was asymptomatic, and the
size of the periapical radiolucency was decreased.
A 40-year-old Saudi female patient with no history of any
systematic disease was presented to the endodontic clinic in
King Abdulaziz University Hospital, Riyadh, Saudi Arabia with a
history of lingering pain for the past couple of days in relation
to mandibular left first molar tooth (#36). Clinical examinations
revealed a sealed composite restoration, no associated swelling
nor sinus tract, but the tooth was tender to vertical percussion
with normal probing depth and asymptomatic to palpation.
Pulp sensibility test (Endo-ice, The Hygienic Corporation, Akron,
OH, USA) showed intense pain that did not subside rapidly.
Radiographic evaluation revealed a coronal radio-opaque
composite restoration with periapical radiolucency in the
mesial root (Figure 2a). Based on the clinical and radiographic
examinations, the tooth was diagnosed as having a symptomatic
irreversible pulpitis with symptomatic apical periodontitis.
Cone-beam computed tomography (CBCT) was carried out
using three‑dimensional (3D) Accuitomo scanner (J. Morita, Kyoto, Japan), with Viewer Plus software (J. Morita, Japan), which
produced a smallest field of view images, to reduce the radiation
dosage. CBCT images revealed two roots and five canals, two
mesial and three distal (Figure 2b). A nonsurgical root canal
treatment was planned accordingly.
The patient received local anesthesia with 2% Lidoocaine and
1:100000 epinephrine, and the rubber dam was placed. Following
the removal of composite filling, careful examination of the pulpal
floor under dental operating microscope (DOM) (OPMI, Carl Zeiss
Meditec, Germany) revealed two mesial canals and three separate
distal canal orifices (distobuccal, middle distal, and distolingual).
Coronal flaring was achieved with size #3 and #4 Gates-
Glidden drills to establish straight line access (Figure 2c), and the
working length was established using Root ZX II. After that, root
canals were prepared using Twisted File Adaptive (TF-Adaptive)
System (SybronEndo, Orange, CA, USA) up to size 35 0.06 for all
canals, and copious irrigation with 5.25% NaOCl and 17% EDTA
solution was carried out during the root canal preparation phase.
Master cones were adjusted according to the working length and a
radiograph was taken (Figure 2d). All canals were dried with paper
points and then filled with gutta-percha and AH26 sealer using
cold lateral compaction technique followed by thermomechanical
compaction. Finally, the access cavity was filled with Coltosol
temporary filling material (Coltosol® F, Coltene, Switzerland) and
the patient was referred to receive final restoration (Figure 2e &
2f). The patient was scheduled for a follow-up appointment after 6
months, but unfortunately, she missed her appointment.
Adequate root canal therapy requires locating, shaping,
cleaning, and obturating all root canal system to prevent posttreatment
disease, pain, and/or complications of endodontically
treated tooth .
Different teeth morphological variations exist which make the
root canal treatment more challenging. Therefore, the clinician
must be familiar with such variations and use the available tools
to negotiate and treat the root canal system and improve the
treatment outcomes [27,28].
The presence of an extra canal in the distal root of mandibular
first molar is called middle distal canal. The prevalence of a middle
distal canal had been reported to range from 0-3% in different
ethnic groups [18,19,21,29-35].
In a recent study by Filpo-Perez et al. in Brazilian population
using μ-CT analysis, the prevalence of one canal in the distal root
of mandibular first molar was in 76%, two canals in 13%, three
canals in 8%, and four canals in 3% of the samples .
Moreover, several case reports of mandibular first molar
with more than two canals in the distal root have been existed
in the literature [10,36-51]. In this report, the two cases were
having one distal root with three root canals, which were similar
in the morphological variations to the previous reported cases
Conventional periapical radiographs taken in different
angulations is necessary to aid in detection of any morphological
variations of root canal anatomy of teeth . If this technique
fails in the detection, CBCT can be used which help in better
detection of such variations . In the first case, different angled
periapical radiographs were able to detect the morphological
variations, while in the second case, CBCT was taken which aid
in the detection of root canal anatomy and management of the
Root-filled teeth with a retained separated instrument had
no effect on treatment outcome , while a lower healing rate
was reported in other studies . In case #1, the separated
instrument in MB canal was bypassed which facilitate shaping and cleaning procedures of the root canal, and this led to the decrease
in periapical lesion during the follow-up visit.
Furthermore, the use of magnification tools in endodontics
by the means of magnifying loupes and DOM will aid in the
proper inspection of the pulp chamber floor and detecting these
variations which could not be seen easily by naked eyes . The
first case was managed under magnifying loupes, while the second
case was managed under DOM, which enhanced the exploration of
the floor of the pulpal floor and detection of canal orifices.
The clinician should be aware of the variable anatomical
variations of mandibular molars. It is important to utilize all the
available diagnostic tools to find and treat the whole root canal
system. Moreover, the proper knowledge of root canal anatomy,
angled periapical radiographs, good access cavity preparation,
proper exploration of pulpal floor under magnification, and CBCT
analysis are important prerequisites for a successful treatment