A Case Report of Occurrence of Type B Radix Entomolaris in Permanent Mandibular First Molars

CASE DESCRIPTION

An 8-year-old female patient reported to the department of pediatric and preventive dentistry with chief complaint of pain in lower left and right back tooth region since a month. Pain was insidious in onset, moderate in intensity, intermittent and localized which aggravates on eating sweet food and relieves on its own. On intraoral examination, a deep occlusal caries (ICDAS 5) was seen in 36 and 46. An intraoral periapical radiograph (IOPA) was taken for 36 and 46 (Fig. 1). IOPA of 36 showed loss of lamina dura and widening of periodontal ligament (PDL) space at apical third of accessory root and widening of PDL space at apical third of distal root. Radiolucency on occlusal surface of crown of 36 involving enamel and dentin approaching pulp (Fig. 2). IOPA of 46 revealed loss lamina dura at apical third of distal root and widening of PDL space at apical third of all three roots. Radiolucency on occlusal surface of 46 involving enamel and dentin approaching pulp (Fig. 3).

Based on clinical and radiographic findings a diagnosis of apical periodontitis was given for 36 and 46. On the radiograph, an accessory root was found in relation to 36 and 46 therefore a diagnosis of radix entomolaris was given for 36 and 46.

Oral prophylaxis and excavation and review for 36 and 46 was advised. Excavation and review was done for 46, no exposure of pulp tissue was noticed after removal of infected dentin further which calcium hydroxide dressing (Dycal) was placed followed by IRM restoration. Patient was recalled after a month for follow-up.

DISCUSSION

The present article reports the presence of one extra root in relation to mandibular left and right first molar tooth which was an incidental finding on IOPA. There have been several reports of the occurrence of supernumerary roots in both permanent and primary mandibular molars of different populations. But studies of the prevalence of extra root variants in Indian population are few in number. In a study done by Nagaveni et al.,⁸ the author found that the prevalence of RE was 4.5% in permanent mandibular first molars. When distribution was seen, 7 teeth showed the presence of unilateral RE whereas only in one case of bilateral occurrence was seen. Nagaveni et al.³ did a study in pediatric population of Davangere where the total occurrence of three rooted primary mandibular first molars among the study subjects was 1.3% and no bilateral occurrence was seen. In another study by Nagaveni et al.,⁴ the total occurrence of three-rooted primary mandibular second molars among the study participants was 6.5%, with bilateral occurrence of 2.6%.

There has been seen the ethical and racial association of RE. Tu et al. found a prevalence of 21.1% using periapical radiographs and 33.33% using the cone-beam computed tomography in Taiwanese subjects.⁹ In Mongoloid traits such as Eskimo, Chinese, and American Indians, it has been reported that RE seen with a frequency ranging from 5–30%. Because of its high prevalence in these populations, the RE is considered to be a normal morphological variant (eumorphic root morphology). In Caucasians, low frequency of 3.4–4.2% has been found and considered to be unusual or dysmorphic root morphology.⁹

The identification and external morphology of RE was described by Carlsen and Alexandersen.¹⁰ They gave four variants of RS on mandibular molar tooth namely A, B, C and AC (Table 1). RE a distolingual root exhibit diverse morphologic features varying from severe curvature to an underdeveloped conical form.^1,11,12 Based on the anatomy of the extracted samples and the bending of ISO 10 files after scouting of the root canal in the RE, three types of curvature were detected: (I) straight or no curvature; (II) coronal third curved and straight continuation to the apex; and (III) curvature in the coronal third and buccal curvature from the middle third or apical third of the root.^1,11,12 Song et al.¹³ have suggested a new classification based on morphologic characteristics which were assessed using cross-sectional CBCT. Type I: no curvature; type II: curvature in the coronal third and straight continuation to the apex; type III: curvature in the coronal third and additional buccal curvature from the middle third to the apical third of the root; small type: root length less than half that of the distobuccal root; conical type: cone-shaped extension with no root canal. A thorough inspection of the preoperative radiograph and interpretation of particular marks or characteristics, such as an unclear view or outline of the distal root contour or the root canal, can indicate the presence of a “hidden” RE. To reveal the RE, a second radiograph should be taken from a more mesial or distal angle (30 degrees). This way an accurate diagnosis can be made in the majority of cases.^1,12,13

Various clinical implications of extra roots in permanent mandibular first molars have been mentioned in literature. During endodontic therapy, RE/RP pose a great endodontic challenge, as incomplete pulp extirpation due to missed canal can result in treatment failure.^1,13 Dentists should be familiar with multiple root anatomy to avoid missing canals. A severe root inclination or canal curvature, particularly in the apical third of the root (in type III RE), can cause shaping aberrations such as straightening of the root canal or a ledge that displays a loss of working length in the ledge canal.^1,13–16 Calberson¹² recommend using flexible nickel–titanium rotary files to increase the chance of centering the canal third and orifice relocation. Nevertheless, unexpected complications (such as instrument separation) occur and are more likely to happen in the RE due to the severe curvature or narrow root canals. Also, the access cavity must be modified in a distolingual direction in order to visualize and treat the RE, this results in a trapezoidal access cavity. After relocation and enlargement of the orifice of the RE, the author suggested initial root canal exploration with small files (size 10 or less) and creating a gliding path before preparation to avoid any of the procedural errors.^15,16 A common clinical problem posed by the three-rooted molar is the possible fracture of the distolingual root. Considering its divergent and curved form, the extra disto-lingual root would be expected to fracture during extraction.⁵

Other clinical difficulties resulting from distolingual root would relate to orthodontic procedures, where the extra root would render movement difficult. It is also hypothesized that the presence of extra root (RE) adds to the stability of molars by providing an increased surface area of attachment to the alveolus.^1,12,13

CONCLUSION

The above-mentioned literature has clearly shown the importance of radix entomolaris during the treatment phase hence diagnosis should be done adequately. Often, we come across cases where there are doubts regarding any diagnosis, in such cases, high diagnostic techniques should be used like CBCT to rule out the suspicion.

REFERENCES

1. Nagaveni NB, Umashankara KV. Radix entomolaris and paramolaris in children: a review of the literature. J Indian Soc Pedod Prev Dent 2012;30(2):94–102. DOI: 10.4103/0970-4388.99978.

2. De Moor RJ, Deroose CA, Calberson FL. The radix entomolaris in mandibular first molars: an endodontic challenge. Int Endod J 2004;37(11):789–799. DOI: 10.1111/j.1365-2591.2004.00870.x.

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4. Nagaveni NB, Poornima P, Valsan A, et al. Prevalence of three-rooted primary mandibular second molars in Karnataka (South Indian) population. Int J Pedod Rehabil 2018;3(1):33–35. DOI: 10.4103/ijpr.ijpr_23_17.

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