Endodontic management of a four rooted retained primary maxillary second molar.

The presence of accessory roots is rare in the primary dentition. Complete knowledge and understanding of tooth anatomy is essential to carry out high quality dental treatment with excellent outcome. In addition, the persistent primary tooth and its missing permanent successor in the dental arch pose several hurdles in front of the clinician due to doubtful survival of primary tooth. In this paper, highlights the root canal treatment of a rarest four rooted retained primary maxillary second molar.

INTRODUCTION

Thorough knowledge of the internal anatomy of root canal system is utmost essential to obtain high quality endodontic treatment and long-term success. Anatomic variations are in the tooth morphology such as the presence of additional root/canal or both warrant modifications in the design and extent of access preparation to allow thorough cleaning, shaping and sealing of root canal system.

Routinely primary maxillary molars accompany three roots and three root canals; named as mesiobuccal, distobuccal and palatal based on the location. Occurrence of extra roots is lower in primary teeth as compared with permanent dentition.[123] Cases have been reported about the presence of additional root in the primary mandibular molars;[45] however, at least one case of primary maxillary molar with additional root has been reported in the literature.[6]

In few patients, clinician may find the presence of persistent primary teeth. At times, these accompany the absence of its successor tooth/bud. A retained primary tooth that occludes adequately with its counterpart and bears satisfactory status of crown and roots with sound periodontal integrity may serve for several years.[7] Persistence of primary teeth is linked to various factors such as impaction[8] or intrabony migration[9] of successor tooth and congenital absence of permanent successor.

Treatment of such cases may vary depending upon the clinical situation, for instance, presence or absence of its permanent successor, need for orthodontic correction due to malocclusion, presence of deep caries, existence of infraocclusion and extensive mobility of retained primary tooth due to extensive root resorption.

In the light of above context this paper, highlights the endodontic management of a retained primary maxillary second molar with the rarest occurrence of four separate roots.

CASE REPORT

An 18-year-old male patient reported to the Department of Conservative Dentistry and Endodontics with the complaint of pain in the left upper posterior region of the mouth since 1 week. Intraoral clinical examination of the patient revealed the presence of retained primary second molar in first and second quadrant of the oral cavity and absence of maxillary second premolars; however, there was no retained primary tooth in the mandibular arch. Remaining teeth except third molars were present in the oral cavity in their usual anatomic position. The left side primary second molar was deeply carious. The primary tooth had similar cusp-fossa relationship alike adjacent permanent teeth and infraocclusion was not clearly visible. Patient had Angle's Class I molar relationship. Furthermore, there was the absence of any obvious crowding or spacing in the permanent dentition. Radiographic examination of the left primary second molar showed the presence of deep caries involving pulp space. Furthermore, the presence of extra root in the primary left second molar and congenital absence of the second premolar tooth bud was noted, also occlusal height of primary tooth was at similar level as compared to adjacent permanent teeth in intraoral periapical radiograph [Figure 1a]. Patient was recommended following treatment options: (1) Extraction of primary tooth followed by space closure using either crown and bridge placement or implant placement. (2) Extraction of primary tooth followed by orthodontic space closure. (3) Root canal treatment for the same tooth alike permanent tooth and follow-up. Also, in third treatment option patient was informed about the possibility of root resorption or ankylosis leading to tooth loss, which again had to be treated with implant or prosthodontic crown or bridge or orthodontic treatment. Patient insisted on saving the tooth rather than immediate extraction; hence, root canal treatment was planned. After, obtaining patient's consent root canal treatment was initiated under local anesthesia and strict rubber dam isolation. Adequate access preparation revealed four root canal orifices. Working length was measured using electronic apex locator (Root ZX™, Morrita, Tokyo, Japan) and radiographic technique using Ingle's method. Working length radiograph confirmed the presence of four separate roots and canals [Figure 1b]. Biomechanical preparation was done using NiTi rotary endodontic instruments (Protaper™, Dentsply, New Delhi, India) in a crown down manner. 17% ethylenediaminetetraacetic acid (EDTA) and urea peroxide paste (Glyde™, Dentsply, New Delhi, India) was used as canal lubricant along with 3% sodium hypochlorite as irrigating solution. Apical canal size was prepared until size F3 for all the canals. After complete instrumentation, all canals were flushed with 17% EDTA solution to remove the smear layer followed by final flush with 5% sodium hypochlorite solution. Later on canals were completely dried using absorbent paper points (Dentsply, New Delhi, India) and all the root canals were obturated using resin based sealer (AH Plus™, New Delhi, India) and Gutta-percha points (Protaper Gutta Percha™, Dentsply, New Delhi, India) [Figure 1c] and the access was restored with dental composite (Ceramax Mono™, Dentsply, New Delhi, India). Post-treatment radiograph showed adequate obturation [Figure 1d] and the patient was asymptomatic.

Figure 1

(a) Pre-operative radiograph showing the presence of deep caries involving pulp space in retained the left primary second molar with absence of its permanent successor. Note the presence of four roots in same tooth. (b) Working length radiograph confirmed the existence of four roots. (c) Clinical view of the access preparation showing the four obturated canals. (d) Post-obturation radiograph

DISCUSSION

This case reported the rarest presence of four separate roots and four canals in retained primary maxillary second molar. Retained primary teeth may remain unchanged for many years even after normal exfoliation time.[10]

Usually, the treatment choice for such teeth is extraction of primary teeth followed by orthodontic correction and space closure. However, at times the absence of its permanent successor tooth bud as well as minimal or absence of the dental arch crowding may necessitate for other conservative treatment options. Therefore, it is essential to save persistent primary tooth as long as possible, further preserving the integrity of the dental arch as attempted in the present case. In addition, assuming the longer survival of primary tooth in the present case, it was endodontically treated alike permanent tooth. However, the patient was informed about the unpredictable survival of the tooth, which may eventually require orthodontic or prosthodontic intervention.

In a recently published case report the combination of orthodontic treatment to correct dental arch crowding as well as endodontic treatment followed by hemisection of retained primary tooth has been attempted. In this case, the hemisected edentulous area provided the necessary space for orthodontic tooth movement.[11]

Prevalence of additional root in primary mandibular molars is more common than primary maxillary molars and more prevalent in specific racial distribution as well. Also, if present, there is predilection to its bilateral occurrence in at least one-third of the cases.[1213] Anatomic variations of teeth and the jaws are genetically linked, which justifies their specific racial distribution as well.[14]

Incomplete debridement of the root canal system is the most common cause for endodontic treatment failure. In multi-rooted or in teeth with multiple canals the probability of missed canals is more specially in cases where aberrant root morphology and internal anatomy exists. Valuable laws put forth by Krasner and Rankow are indispensible in exploring hidden canals, which may otherwise be left untreated.[15] In conjunction, detailed pre-operative radiographic evaluation and careful exploration of pulp space under high magnification after gaining access are demanded.

Accessory roots are formed alike normal roots resulting from in growth of processes from the epithelial root sheath of Hertwig.[16] The accessory roots in the maxillary molars are located palatally as seen in the present case as well. The presence of additional root has also been linked to genetic mutation.

CONCLUSION

The present case report highlighted the endodontic management of retained maxillary primary second molar with the rarest presence of additional root as well as the need to develop exceptional observation skills on the part of the clinician to recognize any dental anatomic aberrations that may affect the treatment outcome.