Asymmetry in mesial root number and morphology in mandibular second molars: a case report
A 16-year old male patient presented to the Department of Conservative Dentistry and Endodontics with a chief complaint of pain in his lower right posterior region of mouth for one week. The patient revealed a history of mild intermittent pain for the past 2 months, which had increased in intensity since one week ago. The patient reported subjective symptoms of prolonged sensitivity to hot and cold food and drinks. The pain was spontaneous and aggravated particularly at night and required analgesic to get relief from pain. The medical history contained no abnormal data. Clinical examination revealed a deep carious lesion on the proximal surface of right mandibular second molar (tooth #47). Palpation and percussion test of the involved tooth did not reveal any tenderness. The tooth was not mobile and periodontal probing around the tooth was within physiological limits. Thermal testing of the involved tooth with heated gutta-percha (Dentsply Maillefer, Ballaigues, Switzerland) and cold spray (Roeko Endo-Frost, Coltène-Whaledent, Langenau, Germany) caused an intense lingering pain, whereas electronic pulp stimulation (Parkell Electronics Division, Farmingdale, NY, USA) caused an early response. The preoperative diagnostic radiograph showed carious lesion closely approximating the pulp with no signs of periapical changes (). From the clinical tests and radiographic findings, a diagnosis of symptomatic irreversible pulpitis was made and endodontic treatment was initiated.\nRadiographic evaluation of the involved tooth revealed an unusual anatomical configuration suggesting the possibility of the presence of two mesial roots (). The mesial surface of the tooth was restored with composite resin (P60, 3M ESPE, St. Paul, MN, USA) after caries excavation to enable optimal isolation. The tooth was anesthetized using 1.8 mL 2% lidocaine with 1 : 200,000 epinephrine (Xylocaine, AstraZeneca Pharma India Ltd., Bangalore, India). Following rubber dam isolation, an endodontic access cavity was established. On inspection with a DG-16 endodontic explorer (Hu-Friedy, Chicago, IL, USA) under an operating microscope (Roslane Meditech, Haryana, India), the pulp chamber floor revealed three canal openings corresponding to the two mesial and one distal roots (). The mesiobuccal, mesiolingual, and distal canal orifices were located in their regular locations at the angles in the floor-wall junction. Further inspection of the pulpal floor was done for search of other orifices that were absent. Coronal enlargement was done with a nickel-titanium (NiTi) ProTaper SX rotary file (Dentsply Maillefer) to improve the straight-line access. The pulp tissue was extirpated using barbed broaches (Dentsply Tulsa, Tulsa, OK, USA). The working length was initially determined with the help of an apex locator (Raypex5, VDW, Munich, Germany) and confirmed using radiographs taken at different horizontal angulations. The working length radiographs showed three independent root canals in three separated roots (). Cleaning and shaping was done using ProTaper NiTi rotary instruments (Dentsply Maillefer) along with ethylenediaminetetraacetic acid (Glyde File Prep, Dentsply Tulsa) using a crown-down technique. Irrigation was performed using 3% sodium hypochlorite solution (Cmident, Cmident, New Delhi, India). Afterwards, a closed dressing was given with a sterilized cotton pellet in the pulp chamber with access cavity restored with Cavit G (3M ESPE).\nTo confirm this rare and unusual morphology, dental imaging of the tooth with the help of CBCT (Carestream CS 9300, Carestream Dental LLC, Atlanta, GA, USA) was planned. An informed consent was obtained from the patient, and a multi-slice scans of the mandible was performed with a tube voltage of 90 kV and a tube current of 15 mA. All measures were taken to protect the patient from radiation. The involved tooth was focused, and the cross-sectional images were obtained in transverse, axial, and sagittal planes (). All images were analyzed with the help of CS 3D Imaging software (Carestream Dental LLC). Horizontal slices of the molar were obtained at 0.5-mm thickness, and were studied at different levels (coronal, middle, and apical third of the roots) to determine the level of root bifurcation and degree of root separation (). The images confirmed that the right mandibular second molar had 2 mesial roots and 1 distal root with independent canal in each. The mesial roots were well separated and were bifurcated at the level of coronal one third. In contrast, the contralateral mandibular second molar was asymmetrical. It had 2 roots, 1 mesial, and 1 distal with 2 canals in the mesial root and 1 canal in the distal root ().\nAt the second appointment, the patient was asymptomatic. Temporary restoration was removed and irrigation was done with copious amounts of 3% sodium hypochlorite and 17% ethylenediaminetetraacetic acid (EDTA, Prevest Denpro Ltd., Jammu, India). The canals were finally flushed with sterile saline. Master cones were selected by placing cones corresponding to the size of the last finishing file used to the working length and was confirmed radiographically (). The canals were dried with absorbent points (ProTaper, Dentsply Maillefer) and obturation was carried out with ProTaper gutta-percha cones (Dentsply Maillefer) using AH Plus resin sealer (Dentsply Detrey GmbH, Konstanz, Germany). The tooth was then restored with a posterior composite resin core (P60, 3M ESPE). Final radiograph was taken to establish the quality of the obturation (). The patient remained asymptomatic during 1 year follow-up period.