Bilateral presence of two root canals in maxillary central incisors: A rare case study.

Success in root canal treatment is achieved after thorough cleaning and shaping followed by complete obturation of the canal system. Therefore, endodontic therapy requires specific and complete knowledge of the internal and external dental anatomy, and its variations in presentation. The internal anatomy of the maxillary central incisor is well-known and usually presents one root canal system. This case report describes an endodontic treatment of traumatized both maxillary central incisors with two canal systems. Knowledge of dental anatomy is fundamental for proper endodontic practice. When root canal treatment is performed, the clinician should be aware that both external and internal anatomy may be abnormal.

Introduction

The complete biomechanical instrumentation and obturation of the root canal system are mandatory to achieve endodontic success. Thus, a broad knowledge of both the external and internal anatomy of teeth is of great importance for adequate endodontic treatment. Many anatomical studies have declared that maxillary incisors are always comprised of a single root, while variations in the number of lateral canals and/or position of apical foramen are reported.[1] However, recently, maxillary central incisors have been reported with 1, 2, and occasionally 3 root canals. Therefore, it is important that dentists consider the existence of anatomical variations of root canal systems, and that these variations can also be found in the maxillary central incisors.

The present case study describes an endodontic treatment of traumatized both maxillary central incisors with two canal systems and without morphological anomaly of the crown.

Case Report

A 35-year-old female patient was reported to our department with complains of pain in the upper front region of the jaw for the past 1 week. On elaborating the history trauma occurs 2 months before in upper front teeth. On examination, tender on percussion noted in tooth no. 11 and 21. Tooth no. 11 was fractured and tooth no. 21 was intact [Figure 1]. Electrical pulp test revealed delayed positive response in relation to 11 and 21. Intraoral periapical (IOPA) X-ray reveals no periapical changes in relation to 11 and 21. Furthermore, the presence of two canals was evident in all maxillary incisors [Figure 2]. Probably, our case lies under Type II canal according to both Weine and Vertucci type of classification. After the pulp vitality tests and radiographic examination, the teeth were diagnosed with Ellis Class II fracture with Apical periodontitis in 11 and Apical periodontitis in 21. Proposed treatment was endodontic treatment of 11 and 21 followed by restoration with crown. After the initial radiographic examination.

Figure 1

Preoperative clinical picture

Figure 2

Preoperative radiograph

Clinical Procedure

Under local anesthesia tooth 11 and 21 was treated individually. First tooth no. 11 was treated followed by tooth no. 21 after 1 week. The tooth was isolated with a rubber dam and disinfected. The access preparation was performed with high-speed round diamond burs No. 1015 (KG-Sorensen, Barueri, SP, Brazil), under continuous irrigation with water spray. Mesial canal which is a master canal was negotiated with 15 size file (Mani files, Japan). Since the IOPA X-ray reveals the presence of second canals distally, access cavity was extended slightly distally and distal canal orifice was scouted with no. 8 size K file. The root canals were irrigated with 1% sodium hypochlorite solution. The intraoral camera picture shows the presence of two orifices mesiodistally in both central incisors [Figure 3].

Figure 3

Intraoral camera pictures showing two orifices in both 11 and 21

After this procedure, working length was taken [Figure 4]. In tooth no. 11, working length established 24 mm in mesial canal and 19 mm in distal canal where it joins the mesial canal. In tooth no. 21, the working length established was 24 mm in mesial canal and 15 mm in distal canal where it joins the mesial canal.

Figure 4

Working length X-rays of 11 and 21

Then cleaning and shaping was done by using protaper system (Dentsply), up to file number F5 for mesial canal system, and F4 for the distal canal system. Master cone fit was checked with the IOPA X-rays [Figure 5].

Figure 5

Master cone fit of 11 and 21

The right and left permanent maxillary central incisor was obturated by using F5 and F4 Gutta-percha (Dentsply) in mesial and distal canals respectively. The post-operative X-ray was taken to confirm the obturation quality [Figure 6] and access cavities were sealed with temporary material (MD-temp, Meta Biomed). One week later temporary material was replaced by light cure composite (Tetric N ceram, Ivoclar Vivadent).

Figure 6

After Obturation of 11 and 21

Finally, both central incisors were restored with Porcelain fused to metal crowns [Figure 7]. The patient was observed for 3 months through clinical and radiographic examination and the tooth remained asymptomatic.

Figure 7

Postoperative Clinical picture

Discussion

Maxillary incisors are commonly single-rooted with one canal.[1] The description of multiple canals in these teeth is limited to case reports of anomalies known as fusion, gemination or dens invaginatus. When a maxillary incisor presents two roots or two or three root canals, conditions such as fusion, gemination, dens in dente, palatogingival or distolingual groove and some variation in the normal development of Hertwig's epithelial root sheath must be considered.[2] Some case reports illustrated a rare case of two roots in maxillary central incisor with two roots in a normal clinical crown.[3]

In the present case, both clinical examination and pretreatment radiograph showed no evidence of enamel or dentinal invagination, thus making dens in dente or dens invagination are unlikely causative factors. Another developmental anomaly, which may be appeared radiographically similar to this case, is palatogingival or distolingual groove, but clinical examination ruled it out.[4]

Another case report illustrates a rare case of maxillary central incisor with two root canals, without morphological anomaly of the crown.[5] The present report illustrates a rare case of maxillary central incisor with two root canals, also without morphological anomaly of the crown.

A correct diagnosis and evaluation should be made before treating the teeth with unusual anatomy. Radiographic examination with varying angles should be undertaken, when faced with a suspicious image. In the present clinical report, it was possible to visualize the canals through the evaluation of the pre-operative X-ray. The access cavity was extended mesiodistally to improve the visibility and the access for the endodontic instrumentation that was carried out with rotating instruments, considering the canal curvature.[5]

Although the maxillary central incisor has one canal, clinicians need to be aware of unexpected root canal morphology when performing root canal therapy. Surgical Loupes, Endodontic endoscopes, dental operating microscopes are some of the commercially available instruments that can help the clinicians to accomplish these goals.[6]

Presence of two canals

In our case on careful pre-operative evaluation, IOPA X-ray shows presence of two canals in all upper incisors. In central incisors, it looks obvious from the pre-operative X-ray where two canals were located mesiodistally (mesial canal being the master canal), whereas in an intraoperative X-ray [Figure 8], it shows clearly that lateral incisor has two canals mesiodistally where distal canal being the master canal. This is a rare occurrence, which was reported only in one article previously.[6]

Figure 8

Intraoperative radiograph showing two canals in maxillary lateral incisor also

Review of articles related to multiple canals in maxillary central incisor

An electronic systematic survey is made using PubMed internet website in attempt to find articles that were published from 1970 to 2010 regarding maxillary incisor and its unusual morphology. The standard search key term used was maxillary central incisor in combination with two canals, three canals, multiple canals, or unusual morphology.

The list of articles published from 1970 to 2010 is enumerated in Table 1.

Table 1

Articles published so far with anatomic variations in maxillary central incisor from 1970 to 2010

The total number of all articles found with unusual morphology in maxillary central incisor was expressed in terms of percentage among the variants. The result was as follows:

Of 24 articles found

54% of articles published with two roots in maxillary central incisor

33% of articles published with two canals in maxillary central incisor

One article present with three root canals in maxillary central incisor

One article with 4 root canals due to dens invaginatus

One article with three canals in all maxillary incisors.

Our case report had two root canals in all maxillary incisors of which two central incisors were endodontically treated.

Conclusion

Careful preoperative evaluation and diagnosis are essential for endodontics. The clinician should be careful that even the most routine of cases might deviate from the usual and should be always attentive to detect anatomic anomalies.

Clinical Significance

The description of multiple canals in maxillary central incisor is limited to case reports of anomalies known as fusion, gemination or dens invaginatus. Our case report illustrates a rare case of having two root canals in both maxillary central incisors, without morphological anomaly of the crown. Furthermore, our case report had two root canals in all maxillary incisors (two maxillary central and two maxillary lateral incisors).