62276802 2-palatal-roots-case-report-changes
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Title: Maxillary molars with two palatal roots. Report of two cases under the operating microscope
Author: A. Chaniotis1
1DDS, MSc, PhD Candidate, Department of Endodontics, Dental School of Athens, Greece
Keywords: Maxillary molars, palatal root, operating
microscope
Running title: Molars with two palatal roots
Maxillary molars have a highly variable root and canal anatomy. Among the
root canal anomalies of maxillary molars, the least frequent appears to be that of
the palatal root. Anomalous root morphology of maxillary molars, such as two
palatal roots and canals, is infrequently reported. Although most of the clinical
literature on the fourth canal concerns an additional mesiobuccal canal in
maxillary molars, the present article describes the diagnosis and clinical
management of a maxillary first molar and a maxillary second molar with two
separate palatal roots, drawing particular attention to radiographic
interpretation and access refinements.
The variability of the root canal system of maxillary molars poses a constant
challenge for the dentist who wishes to provide successful endodontic treatment.
Walton & Vertucci (1), introducing concepts of internal pulpal anatomy, stated that
lack of thorough knowledge of root canal morphology ranks second as a cause of
treatment failures, only to errors in diagnosis and treatment planning. This means that
having a working knowledge of the number of roots, number of canals per root and
their location, longitudinal and cross-sectional shapes, most frequent curvatures and
root outlines in all dimensions is essential in order to provide high standard
endodontic treatment.
The number, form and configuration of root canals present in maxillary first molars
have been thorough investigated in the literature for almost a century. They are the
largest teeth in volume and of the most complex in root and canal anatomy. The three
individual roots of the maxillary first molar form a tripod. The palatal root generally
is the longer, has the larger diameter and offers the easiest access. It often curves
buccally at the apical one third and can contain one, two or three root canals in
various percentages according to studies of apical canal configurations and case
reports (2). The distobuccal root is conical and may have one or two canals. The
mesiobuccal root may contain one, two or three root canals and is the most studied
root in the mouth. However, in rare cases, roots of maxillary first molars don’t form a
tripod because of the presence of an additional palatal root.
Furthermore, root and canal anatomy of maxillary second molars are similar to those
of first molars. The distinguishing morphologic feature of the maxillary second molar
is that its three roots are grouped closer together and are sometimes fused. They
usually have one canal in each root. Often they have two mesiobuccal canals and
infrequently they have two palatal canals. One study found a 1, 4% incidence of two
palatal roots and canals in maxillary second molars (3).
Although the morphological pattern of double palatal root canal in maxillary molars is
extremely infrequent, dentists should be aware of it when considering endodontic
treatment of these teeth.
Cases reported in this paper provide clues and hints about the predictable endodontic
management of maxillary molars with two palatal roots, drawing particular attention
to radiographic interpretation and access refinements.
Case Report A
A 38-years-old Caucasian female was referred from her general dentist to our
Endodontic Private Practice Clinic for endodontic treatment of her right maxillary
first molar. At the time of the appointment, she presented with signs and symptoms of
irreversible acute pulpitis. The patient’s medical history was noncontributory. As the
same patient had been subjected to endodontic therapy of her right maxillary second
premolar two months prior to her present appointment in our office, we used as
preoperative radiograph the one that was taken two months ago. This was done in
order to avoid unnecessary exposure to a new preoperative radiograph; hence the
diagnosis of irreversible pulpitis was straight forward. The preoperative radiograph
can be seen in figure 1. Thorough examination of the preoperative radiograph reveals
the image of a maxillary molar that appears to have only a mesial and a distal root. A
radiograph with buccolingual superimposition of this type may suggest an anatomy of
two separate palatal roots as stated by Christie et al (4). In addition, root canal space
seemed obliterated. This may be due either in true obliteration or in superimposition
of roots.
The patient was prepared for endodontic therapy and a rubber dam was placed.
Access to the pulp cavity was performed using a diamond bur. Once the pulp cavity
has been reached the completion of the access preparation was accomplished with a
carbide bur with blunt tip in order to keep the pulp floor intact. Irrigation of the pulp
chamber was performed using 5, 25% solution of NaOCl, until bleeding was
controlled. Original access preparation revealed three orifices located mesiobuccal,
distobuccal and distolingual. Although the pulp tissue had been totally removed from
the pulp chamber there was constant bleeding from a spot located mesiolingual to the
access preparation suggesting an extra palatal canal orifice. Access was made wider
on the lingual aspect of the preparation, taking a trapezoid shape rather than a
triangular outline and the existence of a mesiolingual canal orifice was confirmed.
Pulpal floor lines interconnecting the four canal orifices created an X-like formation.
The working length radiograph revealed the anatomy of the four canals (Fig 2). We
classified this case as in type I classification of maxillary teeth with two palatal canals
according to Christie’s classification (4). Routine endodontic treatment was
performed using engine –driven Hero 625 files ( Micro-Mega, Besançon, France)
according to the Hero protocol for medium canals. The whole procedure was
accomplished under the higher magnification provided by a Global entrée-plus
operating microscope ( Global surgicalTM corporation, St. Louis, USA) . The view of
the canal orifices after the completion of cleaning and shaping procedures can be seen
in figure 3.
Obturation was performed with thermoplasticised gutta-percha using the elements
obturation unit (Sybron Endo, Redmond WA, USA) and AH-plus sealer (Dentsply,
DeTrey, Germany). Postoperative radiograph can be seen in figure 4.
Case Report B
A 45-years-old Caucasian female was referred from her general dentist to our
Endodontic Private Practice Clinic for endodontic treatment of her left maxillary
second molar. The patient’s medical history was noncontributory. The tooth had
become symptomatic after preparing it to accept a bridge. The preoperative
radiograph can be seen in figure 5. Thorough examination of the preoperative
radiograph reveals an image of superimposed roots similar to that of the first case
reported. A diagnosis of irreversible pulpitis was made and the patient was prepared
for endodontic therapy. A rubber dam was placed and access was achieved using a
diamond bur. After initial access to the pulp chamber, a carbide bur with blunt tip was
used for the completion of access preparation. Irrigation of the pulp chamber was
performed using a 5, 25% solution of NaOCl. After initial bleeding control and pulpal
floor exploration three orifices were detected (mesiobuccal, distobuccal and
distolingual ). The three orifices were enlarged using the hero shaper orifice opener
(Micro-Mega, Besançon, France). The pulpal floor was dried with cotton pellets and
visualized under the higher magnification provided by a Global entrée-plus operating
microscope ( Global surgicalTM corporation, St. Louis, USA). The pulpal floor lines
interconnecting the three orifices seemed to extend mesiolingualy. Access
enlargement was performed at the mesiolingual aspect of the original access cavity
preparation using a non cutting tip carbide bur. Visualization of the pulpal floor
revealed an extra mesiolingual canal orifice. Pulpal floor lines created an X-like
formation. Routine endodontic treatment was performed using engine –driven Hero
625 files ( Micro-Mega, Besançon, France) according to the Hero protocol for
medium canals. The whole procedure was accomplished under the higher
magnification provided by a Global entrée-plus operating microscope ( Global
surgicalTM corporation, St. Louis, USA). The view of the canal orifices and
interconnecting pulpal floor lines after the completion of cleaning and shaping
procedures can be seen in figure 6. Obturation was performed with thermoplasticised
gutta-percha using the elements obturation unit (Sybron Endo, Redmond WA, USA)
and AH-plus sealer (Dentsply, DeTrey, Germany). Postoperative radiograph can be
seen in figure 7. We classified this case as in type II classification of maxillary teeth
with two palatal canals according to Christie’s classification
Discussion
The occurrence of maxillary molars with two palatal roots or two canals on the palatal
root is not frequent. It is speculated that maxillary molars with two palatal roots may
be encountered once every 3 years in a busy endodontic practice (4).
Thews et al. (5) reported two aberrations in palatal root of two maxillary first molars.
The first case had two totally separated palatal roots, with two distinctly eccentric
orifices, while the second case had two palatal orifices, centrally located, with two
root canals which joined at the apex. While, Wong (6) reported a case where final
radiograph revealed a trifurcation in palatal root and he ended up with a first
maxillary molar with three separated foramina in one palatal root.
Deveaux (7) found a second maxillary molar with two well-separated palatal roots
and pointed out the fact that unusual massive coronal morphology should attract
attention of dentist during clinical examination of any case.
Studies report an incidence between 0.4% and less than 2% of more than one palatal
canal in maxillary molars (8, 9). Libfeld and Rotstein (8) in a sample of 1200 teeth
reported an occurrence rate of 0.4% for the maxillary second molar. Stone et al. (9)
examined approximately 500 extracted upper first and second molars and reported a
low incidence of less than 2% cases, where more than one main palatal canal existed.
Recent studies report a 1.4% incidence of the maxillary molars to have second palatal
roots (3). Cleghorn et al. (10) , in a recent literature review regarding the root canal
system of maxillary first molars, came up with a percentage of 99% cases of one
distinct palatal root.
Anatomical variations of the double palatal root canal system in maxillary permanent
molars have been classified by Christie et al. (4) . They gathered 16 ended cases of
upper molars and 6 extracted molars with 2 palatal roots and came up with a
classification of three different types of molars with two palatal roots, according to the
root separation level and their divergences with some overlap between the groups.
Type I maxillary molars have two widely divergent palatal roots. Type II maxillary
molars have four separate roots also that are shorter and run parallel, while type III
maxillary molars have the double palatal root canal system encaged with the
mesiobuccal canals in a web of root dentin. Type III maxillary molars have three roots
and a double canal system in the palatal root. They also resumed that the incidence is
higher in second than in first maxillary molars.
Baratto-Filho et al. (11) reinforced the possibility of variations in internal anatomy of
human teeth and their importance in performing successful endodontic treatment by
reporting a root canal treatment in a first maxillary molar with two separated palatal
roots and two extracted second molars, one with two palatal roots and one with one
palatal root and two distinct root canals. They suggested a IV category in witch the
second canal of the palatal root fused with the mesiobuccal root up to the apical level.
Whatever type of double palatal canal system is encountered, the location and
management of all anatomy is imperative to endodontic success. In the present paper
we reported two cases of double palatal canal system in maxillary molars, drawing
special attention to radiographic interpretation and access preparation.
Indistinct images of palatal roots in preoperative radiographs should alert the clinician
for the possibility of a double palatal canal system. Sometimes four separate root
apices can be seen on an angled preoperative radiograph. In a type II maxillary molar,
such as the one reported in the second case, a radiograph with buccolingual
superimposition makes the molar appear as having only a mesial and distal root.
The distobuccal root in preoperative radiographs of type III variation has been stated
to stand alone or even diverge to the distobuccal. These are radiographic clues that
should alert the clinician.
Clinically, the distance between the lingual cusps of a maxillary molar with double
palatal canal system have been stated to be greater than usual. Periodontal and root
probing in these cases will often help in determining the root trunk.
In both cases presented here, access preparation was made wider on the lingual aspect
taking a rather trapezoid than a triangular outline. The conservation of tooth structure
must be kept in mind when establishing an endodontic access. The traditional
triangular access opening is often too constricted to allow straight-line access in
maxillary molars. Thomas et al. (12) found that 81% of the maxillary first molars they
studied had a trapezoidal pulp chamber and that the use of a trapezoidal access cavity
was warranted. Christie and Thomson (13) have recommended modifying the outline
to a rather ovoid one. They believe that this outline provides better access for the
detection of all additional canals.
Visualization of the pulp floor under magnification also facilitates the detection of
extra canals. In both cases, the interconnecting pulpal floor lines of the orifices,
visualized under magnification, created an X-like formation. This formation of pulpal
floor lines in maxillary molars should alert the clinician for the existence of a double
palatal canal system.
In the first case report, constant bleeding from the pulp floor led us to the detection of
the mesiolingual canal orifice. This finding may often help the detection of extra
canals when teeth with vital pulp are subjected to endodontic procedures. In the
second case report, visualization of the pulpal floor lines that extended mesiolingualy
led us to the detection of the extra mesiolingual palatal canal.
Both case reports contribute to our understanding of the complexity of the root canal
morphology found in maxillary molars. Although such cases occur infrequently,
clinicians must be aware of them. Clinical and radiographic aids are provided for the
detection of such aberrations in palatal root canal morphology. Knowledge of possible
variations in internal anatomy of human teeth is important for successful endodontic
treatment.
Fig 1. Preoperative radiograph of the right maxillary first molar
Fig 2. Working length determination radiograph of the right maxillary first molar
Fig 3. Pulp floor photograph of the right maxillary first molar after the completion of the cleaning and shaping procedure (Original magnification x16, Global entrée plus microscope)
Fig 4. Postoperative radiograph of the right maxillary first molar
Fig 5. Preoperative radiograph of the left maxillary second molar
Fig 6. Pulp floor photograph of the left maxillary second molar after the completion of the cleaning and shaping procedure (Original magnification x16, Global entrée plus microscope)
Fig 7. Postoperative radiograph of the maxillary molar
References
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preparation in Cohen’s and Hargreaves ‘Pathways of the pulp’ 9th ed. ,
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