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Title
Endodontic Treatment of Hypertaurodontic Mandibular Molar Using Reciprocating Single‑file System: A Case Report
Author(s)
C, do, Nascimento, A; A, F, Marques, A; C,
Sponchiado‑Junior, E; F, R, Garcia, L; M, A, de, Carvalho, F
Journal Bulletin of Tokyo Dental College, 57(2): 83‑89 URL http://hdl.handle.net/10130/5706
Right
Description
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Molar Using Reciprocating Single-file System:
A Case Report
Adriano C. do Nascimento1), André A. F. Marques1), Emílio C. Sponchiado-Júnior2), Lucas F. R. Garcia3) and Fredson M. A. de Carvalho1)
1) Department of Endodontics, Superior School of Health Sciences, State University of Amazonas,
69050-030, Manaus, AM, Brazil
2) Department of Endodontics, School of Dentistry, Federal University of Amazonas, 69077-000, Manaus, AM, Brazil
3) Department of Restorative Dentistry, Araçatuba School of Dentistry, Universidade Estadual Paulista,
16015-050, Araçatuba, SP, Brazil
Received 2 November, 2015/Accepted for publication 10 December, 2015
Abstract
Taurodontism is a developmental tooth disorder characterized by lack of constriction in the cementoenamel junction and consequent vertical stretch of the pulp chamber, accompanied by apical displacement of the pulpal floor. The endodontic treatment of teeth with this type of morpho-anatomical anomaly is challenging. The purpose of this article is to report the successful endodontic treatment of a hypertaurodontic mandibular molar using a reciprocating single-file system.
Key words: Endodontics — Root canal — Biomechanical preparation — Taurodontism — Reciprocating motion
Introduction
Taurodontism occurs due to the failure of Hertwig’s epithelial root sheath to invaginate at the appropriate horizontal level9,10,14). It may also be associated with several genetic disorders, including Klinefelter or Down’s syndrome, and development disorders, such as ectodermal dysplasia19).
An elongated pulp chamber and the absence of cervical constriction at the cementoenamel junction are the most prominent features of a taurodontic tooth3). Such teeth can be classified as hypo-, meso-, or hypertaurodontic depending on the distance from the highest point of the pulp chamber roof to the lowest point of the floor (Fig. 1)20). The anomaly is almost exclusively found in the premolars or
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molars, with a significantly higher prevalence in the maxillary second permanent molar, and may involve one or more teeth, with unilateral or bilateral distribution19).
From the endodontic point of view, coronal access, initial exploration, preparation, and root canal filling are all challenging with taurodontic teeth7,15). Moreover, the volume of the pulp chamber is greater in such cases.
This means that clinical procedures such as coronal opening can be hindered due to an unusually large volume of blood flow, which may be mistaken for perforation7,15). Meanwhile, the short roots and apical displace- ment of the pulpal floor can indeed lead to perforation during coronal access3).
The introduction of new instruments and techniques over recent years has changed the approach to endodontic therapy5). One of the latest innovations is reciprocating motion, which allows an instrument to periodically rotate around its axis, alternating between movement 170° counter-clockwise and 50°
clockwise5,13). Reciprocating instruments are made of a special Ni-Ti alloy called M-Wire.
Once formed, the instrument is subjected to a thermal process which significantly improves its flexibility and mechanical strength in comparison with instruments made of con- ventional Ni-Ti5,13). In addition, in terms of kinematics, the working time with recipro- cating systems is 4 times shorter than that with traditional rotary systems, as only one instrument is needed for preparation of the root canal5,13). The purpose of this report is to describe the successful endodontic treatment of a hypertaurodontic mandibular molar using a reciprocating single-file system.
Case Report
A 17-year-old girl was referred to the Clinic of Endodontics at the Superior School of Health Sciences, State University of Amazonas, complaining of spontaneous pain in the mandibular left second molar. Her medical and family history revealed no significant findings, and an extraoral examination no signs of any pathology. Intraoral examination revealed an extensive carious lesion in the buccal-occlusal surface of the mandibular left second molar (tooth #37), with a positive response to the cold sensitivity test (Endo- Ice, Coltene/Whaledent Inc., Cuyahoga Falls, OH, USA). The tooth was not sensitive to the vertical percussion test. Radiographic examination was performed to determine the depth of the carious lesion. The results also revealed features consistent with a diagnosis of hypertaurodontism: the dimensions of the
Nascimento AC et al.
Fig. 2 Preoperative intraoral periapical radiograph of tooth #37 showing hypertaurodontism
Fig. 1 Diagram of normal tooth and 3 subtypes of taurodontic tooth:
hypo-, meso-, and hypertaurodontic20)
Normal Hypotaurodontism Mesotaurodontism Hypertaurodontism
pulp chamber were significantly larger than normal (TI 40–75)20); root shortening; and apical displacement of the pulp chamber floor (Fig. 2). A panoramic radiograph was also requested as multiple taurodontic teeth were suspected. The results confirmed bilateral hypertaurodontism in teeth #17, 27, and 47 (Fig. 3). Based on these findings, irreversible acute pulpitis associated with hyper- taurodontism was diagnosed in tooth #37.
There were no signs or symptoms indicating the need for endodontic treatment in the remaining taurodontic teeth.
Written informed consent was obtained from the patient before commencing treat- ment. First, tooth #37 was anesthetized with 2% Xylestesin (Cristália Produtos Químicos Farmacêuticos Ltda., Itapira, SP, Brazil) and the operative field isolated with a rubber dam. The subsequent procedures were per- formed with the aid of an operative optical microscope (DF Vasconcelos, Valencia, RJ, Brazil). The carious lesion was removed with a spherical diamond bur (No.1013, KG Sorensen, São Paulo, SP, Brazil) coupled to a high-speed device (Extra Torque 605C, Kavo, Joinville, SC, Brazil). The pulp chamber was accessed using a tapered flame-shaped bur (No.2200, KG Sorensen), at which time blood flow was observed to be strong. The pulp tissue
was removed with sharp curettes, followed by copious irrigation of the pulp chamber and root canals with 2.5% NaOCl solution (Biodinâmica, Ibiporã, PR, Brazil). A glide path was then created for both root canals (mesial and distal) with sizes 10, 15, and 20 K-type files (Dentsply/Maillefer, Ballaigues, Switzerland). The remaining radicular pulp was removed during this procedure.
The working length was determined as 19.5 mm in both root canals by using an electronic apex locator ( Joypex 5, Denjoy, Hunan, China) and confirmed radiographi- cally (Fig. 4).
Fig. 3 Panoramic radiograph showing bilateral mandibular (#37 and 47) and maxillary (#17 and 27) second molars with hypertaurodontism (circle)
Fig. 4 Working length determined with electronic apex locator
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Root canal preparation was performed with the R50 (Reciproc system, VDW GmbH, Munich, Germany) coupled to a 6:1 contra- angle handpiece (VDW Silver Reciproc, Sirona Dental Systems GmbH, Bensheim, Germany) powered by an electric motor (X-Smart Plus, Dentsply/Maillefer) in the “RECIPROC ALL”
mode in accordance with the manufacturer’s recommendations. The Reciproc R50 instru- ment was used due to the large amplitude of the root canals. The instrument was inserted 3 times in a slow in-and-out pecking motion.
A Glyde File Prep (Dentsply/Maillefer) was used to lubricate both root canals during preparation. Each instrument was used to prepare only one root canal. After each insertion, the instrument was removed for cleaning with sterile gauze and the root canal irrigated again with 2 ml of 2.5% NaOCl solution (Biodinâmica). At the end of prepa- ration, 1 ml of 17% EDTA (Biodinâmica) was applied for 3 min to remove the smear layer, followed by final irrigation with 2 ml of 2.5%
NaOCl.
The root canals were dried using sterile paper points (VDW GmbH). Root canal filling was performed with Sealapex sealer (SybronEndo, Collins West Orange, CA, USA) and a size R50 gutta-percha master cone (VDW GmbH) (Fig. 5) using thermome-
chanical technique and a size 80 McSpadden (Fig. 6). After filling, the pulp chamber was cleaned to remove excess gutta-percha and sealer. Glass-ionomer cement (Vidrion R, SS White, Rio de Janeiro, RJ, Brazil) was then used to perform a temporary restoration of the coronary cavity. After 7 days, the temporary restoration was removed, and a final restora- tion with composite resin (Z250, 3M ESPE, St.
Paul, MN, USA) was performed in accordance with the manufacturer’s instructions (Fig. 7).
The patient returned to the clinic 12 months later for follow-up clinical and radiographic examinations, which revealed no painful symptomatology or periapical changes, despite over-filling at the apical portion of the distal
Fig. 5 Radiographic test of Reciproc master cones before filling of root canal
Note root canal enlargement after instrumentation with size R50 Reciproc instrument.
Fig. 6 Root canal after placement of filling material
Fig. 7 Tooth #37 temporarily restored with glass ionomer cement after root canal filling
Nascimento AC et al.
root canal. Hermetic sealing of the pulp chamber and root canals, including the apical foramen, was adequate, and there was no sign of the filling having failed (Fig. 8).
Discussion
The present article describes the successful endodontic treatment of a hypertaurodontic mandibular molar using a reciprocating single-file system. Here, it should be noted that the typical signs of taurodontism can not be observed clinically, as the external morphology of such a tooth will be similar to that of a normal tooth4).
Although frequently associated with other anomalies and syndromes2), taurodontism can also occur as an isolated feature12), as in the present patient, in whom no other associated factors were observed. The endo- dontic treatment of such teeth has been described as complex due to the high degree of variability seen in their morphology, which is likely to make location, negotiation, and instrumentation of the root canal particularly difficult11,12).
Several studies have reported the effective- ness of reciprocating systems in the cleaning and shaping of root canals5,18). The efficacy
In addition, some authors maintain that the use of reciprocating systems must be preceded by glide path creation with manual files6,21), while others report that this procedure is not necessary, especially when large taper instruments are used8,16).
In the present patient, a glide path was created by using a manual file prior to root canal preparation with a reciprocating instrument. Initial negotiation of the root canal is one of the most critical steps in the endodontic treatment of a taurodontic tooth.
Therefore, we decided to create a glide path, even though the amplitude of both root canals (mesial and distal) was large, as this reduces friction between the instrument and the root canal wall, thus preserving the original trajectory during instrumentation1,17).
Moreover, by using the Reciproc system here, we were able to reduce the time required to enlarge both canals, even though the morphological anomalies were severe, something that was confirmed radiographi- cally. Earlier studies have also noted that use of a reciprocating system allows the time taken for root canal preparation to be reduced to 62% of that which would be required with a conventional rotary system5).
In addition, in the present patient, a thermoplastic technique was used for root canal filling as it was believed that this would promote adequate three-dimensional filling of the tooth while minimizing the risk of creating voids within the unusually large pulp chamber13,15). This approach provides a better flow of gutta-percha and sealer than the conventional one, which in turn allows the filling material to adapt better to the pulp chamber and root canal walls, promoting more accurate filling of the anatomical details of the taurodontic tooth13,15).
It should be emphasized, however, that radiography here revealed surplus filling material extruding beyond the root canal limits at the apical portion of the distal root
Fig. 8 Radiograph of tooth #37 obtained at 12-month follow-up examination revealed no failure in root canal filling or periapical lesions, despite surplus material resulting from over-filling at apical portion of distal root canal (circle)
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canal after filling10,13,15). Root canal filling of taurodontic teeth is a challenging procedure due to the large diameter of the apical foramen10). The presence of surplus material after completion of filling, however, does not necessarily mean that endodontic treatment has failed. Indeed, it could be asserted that such surplus rather indicates that treatment has been successful, as the entire root canal system, including the apical foramen, has been hermetically sealed13,15). Also, as can be seen from the results of the follow-up examination in the present case, from the endodontic point of view, calcium hydroxide-based sealers such as Sealapex have proven biological com- patibility, and therefore do not compromise the prognosis10,13,15).
Despite its low incidence, an adequate diagnosis of taurodontism is crucial in imple- menting an appropriate treatment plan. The present report provides further evidence that reciprocating single-file systems such as Reciproc are effective and safe in treating complex clinical cases.
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