F. Baratto-Filho, L. F. Fariniuk, E. L. Ferreira, J. D. Pecora, A. M. Cruz-Filho & M. D. Sous a-Neto.Faculty of Dentistry, University of Ribeirao Preto, Ribeirao Preto, Brazil.
Pontifıcia Universidade Catolica do Parana, Parana, Brazil.
Faculty of Dentistry, University of Sao Paulo, Ribeirao Preto, Brazil.Introduction.
Treatment of the entire root-canal system is essential for the success of root-canal treatment. Thus, it is necessary for the clinician to have knowledge of dental anatomy and its variations.
Maxillary molars are known to have a fourth (mesiopalatal) canal (MB2) located in the mesiobuccal root. Pecora et al. (1992) studied the internal anatomy of 370 maxillary molars by means of clearing and located a second canal in the mesiobuccal root of maxillary first, second and third molars, with frequencies of 25, 42 and 32%, respectively. Clearly, the number of roots and canals can vary, and the literature demonstrates an extensive number of anatomical variations. Beatty (1984) reported a maxillary first molar with five canals, three of them located in the mesiobuccal root. The author warned that initial radiography could produce a false impression of calcified root canals owing to image superimposition.
Martinez-Berna & Ruiz-Badanelli (1983) studied3 38 maxillary first molar sand reported three cases of six canals, with three canals in the mesiobuccal root, two in the distobuccal root and one in the palatal root. The frequency of two palatal roots is low, however, a few cases have been reported in the literature. Stone & Stroner (1981) reported variations of the palatal root of maxillary molars, such as a single root with two separate orifices, two separate canals and two separate foramina; two separate roots, each with one orifice, one canal and one foramen; single root with one orifice, a bifurcated canal and two separate foramina.
Benenati (1985) reported a maxillary second molar with two palatal roots and a groove located in this side of the tooth. According to the author, this groove was the result of the formation of two palatal roots. Bond et al. (1988) reported a case of a maxillary first molar with six root canals, two in each root. Wong (1991) reinforced the importance of knowing the anatomical variations of maxillary molars when he reported a case of a maxillary first molar with the palatal canal trifurcating at the apical level, with three independent foramina. Christie et al. (1991) analysed endodontic treatment in 16 maxillary molars and of six extracted teeth with two palatal roots and classified these 22 molars into three types (I–III), according to the root separation level and their divergences. According to this same classification, Di Fiore (1999a,b) classified as type II – a case of a maxillary first molar with four independent roots. A case report of a maxillary first molar with two palatal roots is presented, as well as a study of the internal anatomy of two maxillary second molars with the same morphology. Case report.
A 38-year-old Japanese female was referred for root-canal treatment of her right maxillary first molar. The clinical diagnosis was irreversible pulpitis.
A pretreatment radiograph was taken, and after placing a rubber dam and disinfecting the area with 70% alcohol, conventional coronal access was performed. After removing tissue located in the pulp chamber, two orifices were observed in the palatal root. The appointment was then concluded with the application of intracanal corticosteroids (Otosporin, GlaxoWellcome, Sao Paulo, SP, Brazil).
The patient returned asymptomatic after 72 h and root-canal treatment was initiated using the crown-down technique with Gates-Glidden burs (Dentsply/Maillefer, Ballaigues, Switzerland) numbers 1–3 at cervical- and middle-thirds of the root canals. Apical preparation was performed with Nitiflex files (Dentsply/Maillefer) attached to the KaVo reciprocal system (KaVo, Biberach, Germany). Canal preparation was accompanied with irrigation using Dakin’s solution (0.5%NaOClwith boric acid). The master apical file was size 40 in all root canals. One master cone was used and obturation was performed with the aid of gutta-percha condensers (Dentsply/Maillefer). Sealer 26 (Dentsply, RiodeJaneiro, RJ,Brazil) was used to seal the canal.
Radiographs taken during treatment showed two independent palatal roots (Fig. 1), which were relatively broad, presenting two distinct foramina at the apical level. This indicates a type I tooth, according to the classification of Christie et al. (1991).
Figure 1. Maxillary molar with four roots.Anatomical study.
(A) Initial pretreatment radiograph.
(B) Instruments placed in their positions.
(C) Fitting of four gutta-percha points.
(D) Obturation of the four root canals with gutta-percha condensers.
Two maxillary second molars with two palatal roots, extracted for unknown reasons from Caucasian patients, were selected for study. Macroscopic and radiographic features of the teeth were recorded (Figs 2 and 3) and conventional access cavities were performed. Root canals were explored by means of FlexoFiles (Dentsply/Maillefer) numbers 15–40. The teeth were stored in 5% sodium hypochlorite, changed every 24 h for 3 days to remove pulp tissue. The teeth were then washed in tap water for 6 h. Specimens were decalcified by immersion in 5% hydrochloric acid changed every 24 h for 2 days. After decalcification, the teeth were washed in tap water for 24 h and dehydrated in alcohol (80–100%). Gelatin with India ink was then injected into the root canals and specimens were cleared in methylsalicylate. The transparent teeth could then be examined and the root canals were observed (Figs 2C and 3D). Clearing of the specimens allowed the observation of two distinct root canals in the palatal roots from pulp floor to apical region.
Figure 2. (A) Occlusal view showing two buccal and two palatal orifices.Discussion.
(B) Radiograph showing four root canals.
(C) Cleared tooth revealing its internal anatomy.
Figure 3. (A) Lateral view of a maxillary molar with two palatal roots.
(B) Occlusal view showing canal entrances.
(C) Radiographic aspect of the tooth.
(D) Cleared tooth.
Anatomical variations can occur in maxillary permanent molars. Although not very common, Christie et al. (1991) speculated that maxillary molars with two palatal roots may be encountered once every 3 years in a busy endodontic practice. Peikoff et al. 1996) observed that 1.4% of maxillary molars may have second palatal roots.
The tooth described in this case report (Fig. 1) had totally separated palatal roots, each with a distinct root canal. This was also true of one of the extracted teeth used for the internal anatomy study (Fig. 2). Thus, they were classified as type I, according to Christie et al. (1991). The other tooth which was used for the internal anatomy study (Fig. 3) had a palatal root with two distinct root canals, but it was fused with the mesio-buccal root up to the apical level. This variation was not described by Christie et al. (1991), thus, we suggest the inclusion of this variety in the classification as type IV.
When indistinct images of palatal roots are presented in preoperative X-ray images, the clinician must consider the possibility of two palatal roots. Dissociation of images must be performed and, if this anomaly is confirmed, a broad coronal access will allow the correct localization of root canals (Fig. 1B). Location and management of all anatomy is central to endodontic success.
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Benenati FW(1985) Maxillary second molar with two palatal canals and a palatogingival groove. Journal of Endodontics 11, 308-10.
Bond JL, Hartwell G, Portell FR (1988) Maxillary first molar with six canals. Journal of Endodontics 14, 258-60.
Christie WH, Peikoff MD, Fogel HM (1991) Maxillary molars with two palatal roots: a retrospective clinical study. Journal of Endodontics 17, 80-4.
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