|Year : 2015 | Volume
| Issue : 1 | Page : 59-63
Single rooted, single canalled mandibular first molar in association with multiple anomalies: Report of a rarest case with literature review
NB Nagaveni, M Manoharan, Sneha Yadav, P Poornima
Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, Karnataka, India
|Date of Web Publication||4-Jun-2015|
Dr. N B Nagaveni
Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, Karnataka
Source of Support: None, Conflict of Interest: None
Knowledge on variations in roots and canal morphology of teeth is very important for successful endodontic treatment. Most of the times, permanent mandibular first molar (PMFM) usually have two roots one mesial and one distal with three root canals. Although variations in root and canals of this tooth have been extensively discussed in the endodontic literature, existence of a single root with a single canal is not well-documented. The aim of this report is to present an unusual anatomy of the PMFM having a single root and single canal along with other peculiar multiple anomalies such as tooth agenesis, single-rooted maxillary first molars and three rooted primary mandibular second molar in the same patient.
Keywords: Permanent mandibular first molar, root canal treatment, single canal, single root
|How to cite this article:|
Nagaveni N B, Manoharan M, Yadav S, Poornima P. Single rooted, single canalled mandibular first molar in association with multiple anomalies: Report of a rarest case with literature review. Niger J Exp Clin Biosci 2015;3:59-63
|How to cite this URL:|
Nagaveni N B, Manoharan M, Yadav S, Poornima P. Single rooted, single canalled mandibular first molar in association with multiple anomalies: Report of a rarest case with literature review. Niger J Exp Clin Biosci [serial online] 2015 [cited 2022 Jul 1];3:59-63. Available from: https://www.njecbonline.org/text.asp?2015/3/1/59/158171
| Introduction|| |
A sound knowledge of the root canal morphology of the tooth is highly essential to achieve success of root canal treatment. Normally, the permanent mandibular first molar (PMFM) (36, or 46 - FDI tooth notation) exhibits two roots one mesial and other distal with three root canals. However, variations in the number and configuration of both roots as well as root canals can happen and has been extensively discussed in the literature. ,, These variations are mandibular first molar with three roots (distolingual root-Radix Entomolaris , and mesiobuccal root-Radix Paramolaris),  and four roots  with respect to number of roots concerned. When root canals are concerned the variations include mandibular first molar with five,  six  and seven root canals,  middle mesial canal,  and middle distal canal,  four canals in mesial root,  four canals in distal root  and 'C' shaped canal.  All these published reports discussed the cases with more number of roots or canals than normal.
It is also necessary to have a thorough knowledge of the possibility of existence of the lesser number of roots and canals in any teeth. In 2006, Gopikrishna et al.  reported a case of maxillary first molar having a single root with a single canal. Apart from this there are many case reports showing single rooted and single canalled maxillary first molars. , Recently Chaudhari et al.,  have published a case of unilateral single rooted primary mandibular first molar. Existence of PMFM with a single root and single canal is an extremely a rare finding, and only two cases , has been reported in the existing literature. Therefore, the aim of this article is to present a case of such rare entity that is, PMFM with a single root and canal found in a 13-year-old Indian girl patient that can be added to the present list of single rooted PMFM with a single canal. The patient also exhibited other anomalies like agenesis of the second premolar and three rooted primary second molar, single-rooted maxillary molars which too are rarely encountered during clinical practice.
| Case Report|| |
A 13-year-old girl patient was reported to the Department of Pedodontics and Preventive Dentistry with the chief complaint of spontaneous pain in left lower back tooth region since 1-month. Past dental history revealed intermittent pain for the past 1-month, which had increased in intensity for the past 5 days. There was no significant medical history. Intraoral examination revealed a deep occlusal carious lesion in the permanent mandibular left first molar (36 - FDI tooth notation) [Figure 1]. The tooth did not respond to electric or cold sensitivity test but responded positively on vertical percussion when compared with adjacent and contralateral teeth. Preoperative intraoral periapical radiograph and orthopantamograph showed pulp exposure in relation to left PMFM with radiolucent lesion present at root apex [Figure 2] and [Figure 3]a. On detailed examination of the radiographs, it was evident that the PMFM had a single root with a single canal [Figure 2] and [Figure 3]a. We also noticed single rooted permanent maxillary right and left first molars, three roots in primary mandibular left second molar, which was over retained with no radiographic evidence of root resorption and agenesis of left mandibular second premolar [Table 1] and [Figure 2]. For further confirmation of a single root with a single canal in the PMFM, multiple angulated radiographs were taken. From the clinical and radiographic examination, a diagnosis of chronic periapical abscess was made. The parents of the patient were informed about the treatment modality, and the decision was made to perform routine root canal treatment. Treatment was initiated after obtaining written informed consent from the parents.
|Figure 1: Intraoral photograph showing grossly decayed 19 (arrow) (mirror view)|
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|Figure 2: Orthopantomograph showing single rooted 3, 14, 19, over retained, three rooted K and agenesis of 20|
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|Figure 3: (a-d) Photograph showing various stages of root canal treatment in 19 with a single canal. (a) Arrow shows extra root in K|
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After adequate local anesthesia (2% lignocaine with 1:1, 00,000 adrenaline) (Indoco Remedies Ltd., Mumbai, India) and isolation with a rubber dam an endodontic access opening was done. A single orifice with single root canal was noticed at the center of pulp chamber floor, which was confirmed using dental operating microscope. The working length of the located single canal was first determined using an apex locator and then confirmed on intra-oral periapical radiograph by placing the 15 no. K-file (Mani Inc., Japan) working length was first determined using an apex locator and then confirmed on intra oral periapical radiograph. The canal was instrumented with step-back technique. The apical preparation was done with 50 no. K. The apical preparation was done with 50 no. K file followed by three mix triple antibiotic paste intracanal medicament inside the canal and finally access cavity was sealed with intermediate restorative material (Dentsply, Mumbai, India). Followed by three mix triple antibiotic paste intracanal medicament inside the canal and finally access cavity was sealed with intermediate restorative material (Dentsply, Mumbai, India). Patient was reviewed after 1-month. Irrigation was done with normal saline and 3% sodium hypochlorite. Final rinsing of the canal was performed using 2% chlorhexidine digluconate. After complete biomechanical preparation of the canal, the canal was dried with paper points and obturated with zinc oxide eugenol sealer (Deepak Enterprise, Mumbai, India) and gutta percha points using lateral condensation technique [Figure 3]. Finally, access opening was sealed with Cavit. A postoperative radiograph was taken to confirm the quality of the obturation. Postendodontic permanent restoration of the tooth when was permanent was done using composite build up, followed by placement of a stainless steel crown (3M ESPE, USA) considering the young age of the patient [Figure 4].
|Figure 4: (a) Arrows showing postoperative picture of 19 after composite build up (b) and stainless steel crown placement (mirror view)|
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| Discussion|| |
The present article highlighted the existence of an unusual anatomy of the root and canal in the PMFM. This is the presence of a single root and canal in the molar which is rarely documented in the literature. Until date, only three cases have been reported ,, [Table 2]. Vakebcua De Pablo et al.,  in 2010 and Ballulaya et al.  in 2013 have done a systematic review of the literature on canal morphology of the mandibular first molar. But both of them have not recorded this rare morphology. However, Reuben et al.  earlier to these authors documented this morphological variation in their in vitro study. In this study, of 125 samples of mandibular first molars studied in Indian population, only one sample had a single root and single canal. Later in 2011, Ioannidis et al.,  reported a case of mandibular first molar with single root and canal along with bilateral existence of six maxillary and mandibular first and second molars in a 47-year-old male patient of Greece origin. Recently Sooriaprakas et al.,  found a single rooted mandibular first molar in a 28-year-old male patient belonging to South India. The present article is the second report showing the presence of single rooted and single canalled PMFM in Indian patient. Except Ioannidis et al.,  reported remaining two reports are recorded in the Indian ethnic groups. From this fact, it is evident that future studies are highly essential to provide more knowledge on the existence of mandibular first molar with single root or canal in other ethnic groups, which is highly important from anthropologic as well as forensic point of view.
|Table 2: Reported cases of single rooted permanent mandibular first molar in the literature|
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In the present case, it is also evident that the maxillary first molars (both right and left) exhibited single root with single canals. Only three case reports ,, have been published till date on the existence of maxillary first molars with single roots and canals. In the comprehensive review of Cleghorn et al.,  the presence of three roots in first maxillary molars occurred in an overall percentage of 96.2%, whereas in a percentage of 3.8% first maxillary molars presented two roots. Recently, Ioannidis et al.,  found bilateral presence of maxillary first molars with a single root and a single canal.
Occurrence of extra roots in primary mandibular second molars is a rare phenomenon with only 10 published data available in the literature ,,,,,,,,, [Table 3]. In these published data, five reports ,,,, are epidemiological studies, and remaining are case reports. ,,,, Ramamurthy and Srinivasan,  Winkler and Ahmad  found bilateral occurrence of three rooted primry mandibular first molars (PMFMs). Acs et al.,  reported combination of three rooted primary second molars, talon cusp, shovel incisors and supernumerary tooth in a 7-year-old Hispanic male patient. Recently, Nagaveni et al.,  documented two cases of three rooted PMFMs in Indian patients. The present article shows presence of this unusual clinical entity in association with a single rooted permanent first molars and tooth agenesis.
|Table 3: Reported cases/studies of primary mandibular second molars with three roots in the literature|
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Excluding third molars, mandibular second premolars were the most commonly missing teeth in the Caucasian population. Literature shows association between premolar agenesis and taurodontism anomaly.  In our patient agenesis of mandibular left second premolar was also evident. Hence in overall, the unique feature of the present case is occurrence of three different anatomical and numerical variations within the same patient. These features are not reported in the previous cases of single rooted PMFM making this case as an interesting novel case.
Normally development of roots begins after enamel and dentin formation has reached the future cemento-enamel junction. Prior to root formation the root sheath forms the epithelial diaphragm which will grow horizontally and cover the wide cervical opening into narrow apical foramen. In multi-rooted teeth the epithelial diaphragm undergoes differential growth, which causes the division of the root trunk into two or three roots. Depending on the number of divisions, number of the roots will be formed. In multi-rooted teeth, the epithelial diaphragm is genetically programmed to undergo differential growth, but under the rarest condition this differential growth may fail to take place and this may give rise to the formation of single rooted mandibular first molar.  It is surprising that three types of genetically programmed differential growth is occurred in this patient leading to the development of single rooted permanent molars, trifurcated primary second molar and agenesis of premolar. This relatively harmless condition can provide a boon to future genetic research as there is a unique subset of single root in the permanent molar, supernumerary root in the primary second molar and agenesis of premolar all together co-existing in the same individual.
Radiographic examination of the tooth is an important diagnostic tool for identification of any aberrations in the root or canal during root canal treatment. Radiographs taken from a 20° mesial or distal angulation enhances the chances of detecting unusual root canal configurations.  However, use of cone-beam computed tomography, a new revolution in the endodontic field is more valuable diagnostic tool in detecting such aberrations as it provides a three-dimensional picture of the root and canals. , In the present case, we used conventional radiographs at different horizontal angulations during the entire endodontic procedure, which confirmed the presence of single root and canal. During access opening, a single orifice with a single root canal was found at the center of the pulpal floor and dentine bridge was not evident. The root canal treatment was carried out in a conventional technique, and the tooth was finally restored with stainless steel crown to provide functional rehabilitation for the patient.
| Conclusion|| |
The current case report highlights the uncommon combination of multiple anatomical variations within the same patient showing single rooted mandibular and maxillary first molars, three rooted primary second molar and congenital agenesis of mandibular second premolar. In-depth knowledge and meticulous diagnosis of root variations are highly important to achieve success in the root canal treatment.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3]