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Year : 2015  |  Volume : 5  |  Issue : 1  |  Page : 56-60

Double palatal roots in maxillary second molars: A case report and literature review

Department of Restorative Dentistry, College of Dentistry, Riyadh Colleges of Dentistry and Pharmacy, Riyadh, Saudi Arabia

Date of Web Publication12-Jan-2015

Correspondence Address:
Mohammed S Alenazy
Riyadh Colleges of Dentistry and Pharmacy, P.O. Box 84891,
Saudi Arabia
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1658-5984.149092

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A thorough understanding of internal and external anatomy of various teeth is critical for a successful outcome of endodontic therapy. The aims of this paper were (1) to describe the clinical retreatment of a maxillary second molar with two palatal roots and (2) to review the available literature regarding this anatomical variation. A 45-year-old Saudi female presented for non-surgical retreatment of maxillary left second molar. Careful radiographic and clinical examinations revealed the presence of two buccal and two palatal roots each with a single root canal. Anatomical variations can occur in any tooth; therefore, the clinicians should always anticipate the occurrence of these variations and utilize all the available tools to diagnose and manage them

Keywords: Maxillary second molar, double palatal roots, root canal morphology, root canal retreatment

How to cite this article:
Alenazy MS, Ahmad IA. Double palatal roots in maxillary second molars: A case report and literature review. Saudi Endod J 2015;5:56-60

How to cite this URL:
Alenazy MS, Ahmad IA. Double palatal roots in maxillary second molars: A case report and literature review. Saudi Endod J [serial online] 2015 [cited 2023 Feb 3];5:56-60. Available from: https://www.saudiendodj.com/text.asp?2015/5/1/56/149092

  Introduction Top

The major aim of root canal therapy is to perform adequate biomechanical preparation and to fill the entire root canal system. Failure to do that may lead to post-treatment disease. [1],[2] Therefore, the clinicians should have a sound knowledge of internal and external teeth morphology and their frequent variations to improve the predictability of root canal therapy. [3]

The morphology of the maxillary second molars has been studied by different methods. [4],[5],[6],[7],[8],[9] These teeth may show a considerable variation in their roots number, ranging from one to five. The percentage of accessory palatal root has been reported to range from 1.1 to 1.5%. [4],[7],[8]

The aims of this report were to (1) illustrate the endodontic management of a maxillary second molar with two palatal roots and (2) review the available literature regarding this anatomic variation.

  Case report Top

A 45-year-old Saudi female presented for evaluation of the previous endodontic treatment of maxillary left second molar (#27) prior to fabrication of a full coverage crown. The tooth was filled with a mesio-occlusal amalgam restoration and it was asymptomatic. Preoperative radiographs showed substandard root canal filling and presence of an untreated mesiopalatal root [Figure 1]a and b]. Based on the clinical and radiographic examinations, the tooth was diagnosed as having a previously treated pulp with normal periapical tissues. A non-surgical root canal retreatment was planned accordingly.

Local anesthesia was administered and the tooth was isolated using rubber dam. Following the removal of the coronal restoration, three canal orifices (mesiobuccal, distobuccal and distopalatal) filled with gutta-percha were identified. Careful examination of the pulpal floor under dental operating microscope (Global Dental Microscopes, Global Surgical Corporation, U.S.A) revealed a fourth opening in the mesiopalatal aspect of the pulpal floor. The access cavity outline was modified from a triangular into square shape to establish straight line access for all canals [Figure 1]c. Gutta-percha was removed using ProTaper retreatment system (Dentsply, Maillefer, Ballaigues, Switzerland) and Guttasolv solvent (Septodont, Saint-Maur-des-Fosse, France). The working length was determined using Root ZX II (J. Morita, Tokyo, Japan) and confirmed radiographically. After irrigation with 2.5% sodium hypochlorite (NaOCl), the canals were dried with paper points and filled with non-setting calcium hydroxide (Meta Biomed Co. Ltd., Chungcheongbuk-do, South Korea). Finally, tooth was temporized with Cavit filling (ESPE, Seefeld, Germany).
Figure 1: (a) A preoperative radiograph of tooth #27. (b) Radiographicview after removing root canal fi llings. (c) Occlusal view showing a square-shaped access opening with four root canal orifices.(d) Postoperative radiograph confi rming the presence of two separate and divergent palatal roots

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At the second visit, the canals were instrumented with ProTaper universal files (Dentsply, Maillefer, Ballaigues, Switzerland) to size # F2 in buccal canals and # F3 in palatal canals. Copious irrigation with 2.5% NaOCl was performed during the instrumentation phase. Then, all canals were dried and filled using gutta-percha cones and AH-plus sealer (Dentsply Maillefer, Ballaigues, Switzerland) [Figure 1]d. Finally, the access cavity was filled with a resin-modified glass ionomer filling and the patient was referred to prosthodontic clinic to fabricate a full coverage crown.{Figure 1}

  Discussion Top

Successful root canal treatment depends on thorough biomechanical instrumentation and three dimensional obturation of the entire pulp space. Undetected extra roots or canals are recognized as a major reason for failure of root canal treatment. [1],[2] The present case described an orthograde root canal retreatment of a maxillary second molar with double palatal roots of which the mesiopalatal root was missed during the previous treatment. According to Christie's classification, [10] the tooth had a type I root configuration (i.e. divergent palatal roots and "cow-horn"- shaped buccal roots). The detection of the missed root was first detected radiographically and then confirmed clinically through modification of the access cavity with the aid of dental operating microscope.


The two palatal roots are commonly referred to as mesiopalatal (MP) and distopalatal (DP) roots. [11],[12],[13],[14],[15],[16],[17],[18],[19],[20] Other authors used different terminology including first and second palatal roots, [21],[22],[23] mesiolingual and distolingual roots, [11] or radix mesiolingualis and radix distolingualis. [24]


Four-rooted molars with double palatal roots were reported to occur in 1.1 to 1.5% of maxillary second molars. [4],[7],[8] This anatomic variation was reported in males [11],[12],[17],[18],[19],[20],[25],[26] and females [13],[14],[15],[16],[18],[19],[22],[23],[27],[28],[29] and usually occurs unilaterally either on the right [11],[13],[15],[17],[18],[19],[20],[22],[23],[25],[27],[29],[30],[31] or left [12],[14],[16],[26],[30],[32] side [Table 1]. The bilateral occurrence of this phenomenon has also been documented. [4],[13],[28] Recently, Yang et al.[8] investigated the root configurations of 1957 maxillary molars and reported that the prevalence of two palatal roots was not affected by patient's gender or tooth location (right or left).
Table 1: Previous case reports of maxillary second molars having double palatal roots

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Christie et al.[10] classified maxillary molars with double palatal roots according to the divergence and fusion of their roots into three types: I, II and III. Later on, Baratto-Filho et al. [33] added a new type IV to Christie's classification [Table 2]. Differentiation between types II and type III molars is difficult based on radiographic assessment alone and therefore they are usually grouped together. [4] Most of the previously published cases were type II/III molars [11],[12],[13],[14],[15],[17],[18],[20],[22],[25],[26],[27],[28],[29],[30] followed by types I [16],[19],[21],[23],[30],[31],[32],[33] and IV. [28],[33] Carlsen and Alexandersen [24] classified these teeth according to the side of the crown with which the accessory palatal root is associated [Table 2]. The authors identified 23 second molars in their study of which 18 were classified as radix mesiolingualis, 1 molar as radix distolingualis while the radix mesiolingualis ⁄ distolingualis type was identified in four cases. [24]
Table 2: Classifi cation of maxillary molars with double palatal roots

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Morphological features

Maxillary molars with double palatal roots usually show prominent palatal cusps, causing the crown size to be relatively larger than normal. [24],[32] Yang et al.[8] found that the mean distance between palatal canals orifices was significantly larger (2.84 ± 0.50 mm) than that between the orifices of buccal canals' (2.15 ± 0.82 mm). Therefore, these teeth usually have a square or trapezoidal access cavity instead of the conventional triangular outline. [14],[15],[19],[28]

The radicular morphology of four-rooted maxillary second molars has been also investigated. Each root had a type I root canal configuration. [4],[7],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20],[21],[22],[23],[26],[28],[29],[30],[31],[32],[33] Nevertheless, one clinical case [25] reported a four-rooted second molar with 6 root canals; 2 in each of the buccal roots while each palatal root had 1 canal. Yang et al.[8] found that the average angle among the palatal roots was significantly larger than that between the buccal roots (34.6 ± 16.1° and 21.3 ± 12.2°, respectively). External radicular aberrations such as palate-gingival groove [11],[29] and cervical enamel pearls [10] have also been reported. The co-existence of these radicular anomalies may cause localized periodontal disease and complicate the management of these teeth. [34],[35]

Clinical management

The existence of extra roots in maxillary molars has clinical implications on endodontic treatment. Therefore, the clinicians must make every effort to diagnose and manage such teeth using all the available armamentaria.

Careful interpretation of periapical radiographs exposed at different angulations is an essential tool for detecting morphological variations. [30],[36] Radiographically, an extra root may be suspected when double periodontal ligament spaces (PDLs) are seen on one root side or if PDLs overlap over adjacent roots. [37] Advanced radiographic techniques such as spiral computed tomography (SCT) and cone beam computed tomography (CBCT) are also useful in diagnosing morphological aberrations if conventional radiographic techniques provide limited information and further details are required. [38]

Beside radiographic examination, proper inspection of external landmarks is critical for location of accessory roots. Maxillary molar with two palatal roots usually have a larger-than-usual crown due to the presence of prominent palatal cusps. [24],[32] Careful periodontal probing of cervical area may show radicular grooves or bifurcation of the roots, thus confirming the presence of an accessory root. [10],[11],[13]

Proper design and preparation of access cavity is of utmost importance to visualize and inspect the entire pulp chamber floor. Molars with 2 palatal roots usually have a wide mesiodistal dimension on the palatal side; therefore, the access cavity outline for these teeth will be rectangular or trapezoidal rather than triangular. [10],[13],[14] Furthermore, detailed exploration of pulpal floor under proper magnification and illumination increases the possibility of detecting and treating the entire pulp system in teeth with aberrant morphology. [20],[25],[26]

  Conclusions Top

Although the probability of having double palatal roots in maxillary second molars is low, this variation should be considered while treating these teeth to improve root canal treatment outcome. Awareness of the potential variations in tooth anatomy, careful assessment of preoperative and working radiographs, correct access cavity outline and careful inspection of pulpal floor are essential for diagnosing and treating teeth with such anatomical variation. Beside these diagnostic tools, it is recommended to perform root canal treatment under the dental operating microscope as it provides proper magnification and illumination of the operating field.

  References Top

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  [Figure 1]

  [Table 1], [Table 2]

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1 Endodontic management of a maxillary first molar with two palatal roots: A case report
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