THE FOURTH CANAL IN MANDIBULAR FIRST MOLARS- Case reportsRukoma A.M; DDS, MDent (Restorative Dentistry) 2011
Introduction The success rates of RCT among others depend on practitioners’ knowledge of the internal dental/root morphology that allows:- for accurate location of the canals proper debridement and cleaning together with adequate obturation of the canals and filling of the access cavity.
The use of Magnification adequate lighting and modified accessmay assist in accurate location of the root canals (Amauri et al., 2006).
There is a significant difference in location of canals between using and not using visual aid. Buhrley et al (2003) reported the incidence of finding extra canal in maxillary first molars to be; 17%-without visual aid 63%-when using dental loupes 71%-operating microscope
Visual aidsDental loop with light A Dentist usingsource surgical microscope
Studies show mandibular 1st molars having variable number of root canals. 3-4 canals-majority (Fabra-Compos, 1985; Walker R. 1988; Zaatar el al,1997 and Al- Nazhal, 2004) 5 canal (Baugh, and James, 2004) 6 canals (Martinez-Berna and Bandanelli 1985)
With increasing reports of aberrant canal morphology, dental practitioners need to be extra cautious and think of employing dental visual aids when dealing with these teeth An unidentified, and therefore uncleaned, canal can be a major cause of failure.
Case report-1On 30th may, 2011, a 26 yrs F, patient reported at our clinic with the main complain of; severe toothache not responding to panadol for three days pain was disturbing her sleep.
On examination, a big and deep cavity on bucco-occlusal surfaces of tooth #46 was revealed. Periapical x-ray showed dental pulp exposure.
Upon excavation and access cavity preparation, clearly and separate two root canal orifices were seen in the distal root as well as in the mesial root. The canals were easily penetrated by small K-files (fig.1). the two canals in distal root was located on the buccal and lingual part of the root (fig.2).
Figures 1&2 showing k-files in the rootcanalsFig.1 k-files in 4 different fig. 2: two k-files in theroot canals distal 2 root canals
All canals were prepared and cleaned at working length of 21.5 mm and Master Apical File (MAF) size 35. Obturation was done the same day (single visit technique) and access cavity filled. As up to now, the patient is quite well.
Case report- 2 On 7th June, 2011, a 16-yrs, M, patient presented to KDC with a history of severe toothache on the lower right jaw for 2 days. The pain was worse during night hrs radiating up the same side of his face and ear.
Clinical examination revealed a big and deep cavity involving occlusal, buccal and distal surfaces of tooth #46. Periapical x-ray revealed dental pulp exposure with small apical radioluscence around the apex of the distal root of 46.
Due to direct visualization of the access cavity and floor of PC, two clearly visible canals were seen in the distal root and two in mesial root. In both roots the canals were located on the buccal and lingual sides (fig.3). All canals were easily accessible using k-file #10.
The disto-lingual canal was the smallest of all canals enlarged up to size 20 (MAF), the rest of the canals were enlarged up to MAF size 35. Obturation of the all canals was done after three days and patient is doing fine.
Discussion In both two cases the second distal canals were easily located- because of location and extent of the cavity. This observation indicates that with modifies access cavity a forth canal is likely to be found.
The observation that the reported two cases with four root canals were just within 8 days suggest that, there is substantial number of mandibular first molars with four canals. This is in agreement with Al-Zantal (2004), who said that, “in general, the second canal in distal root is the usual normal”.
Conclusion It is likely there is a substantial number of mandibular 1st molar teeth with two canals in the distal root.
Recommendations Clinicians must always attempt to look for the extra- canals when attending mandibular 1st molars visual aids are needed when doing root treatment Researches are needed to find out the number of root canals in mandibular 1st molars in Zambia population
References Al- Nazhal. S, (1999). Incidence of fourth canal in the root canal treated mandibular first molars in Saudi Arabian sub- population, Int Endod J, 32, 49-52 Amauri F, Fabiana G, Luís C C. (2006) Root canal therapy of a maxillary first molar with five root canals: case report Braz Dent J 17. Baugh, D. and James (2004). Middle Mesial Canal of the Mandibular First Molar: J. Enod 30, 185 Buhrley L J, Barrows M J, BeGole E A. Effect of magnification on locating the MB2 canal in maxillary molars. J Endod 2003; 28: 324–327.
Fabra-Compos, (1985). Unusual root anatomy of manibular first molar J Endod 12, 568-72. Martinez-Bema A and Bandanelli P. (1985). Mandibular first molar with six root canals. J. Endod 11, 348-52 Walker R. (1988). Root form and canal anatomy of mandibular first molar in a southern Chinese Population. Endod. and Dent. Traumatol. 4, 19-22 Zaatar E I. 1, , Al-Kandari A M 2, Alhomaidah S, and Al Yasin I M. (1997). Frequency of endodontic treatment in Kuwait: Radiographic evaluation of 846 endodontically treated teeth J Endod 23, 453-456.
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