Comparative Evaluation of Root Canal Dentin on Efficacy of Smear Layer Removal with Nd:YAG Laser and EDTA after Rotary Instrumentation – SEM Study

Abstract

Aim: To evaluate and compare the efficacy of Ethylenediaminetetraacetic Acid (EDTA) and Neodymium-Doped Yttrium Aluminum Garnet (Nd:YAG) laser in removing smear layer on root canal dentin after rotary instrumentation. Materials and methods: Sixty extracted maxillary incisor teeth were taken, decoronated and standardized to working length of 14 mm from the apex. All the canals were prepared with NiTi rotary files, rinsed with 1% sodium hypochlorite (NaOCl) and divided into three groups. Group 1 constituted the negative control and was rinsed with saline, group 2 with EDTA and group 3 was exposed to Nd:YAG radiation. The specimens were split longitudinally into two halves and examined under SEM with 1,000× magnification at levels of 2 and 6 mm from apical foramen. Photomicrographs were evaluated by the Hulsmann scoring system and results were tabulated. Scores 1 and 2 were grouped as clean walls and scores 3, 4 and 5 were grouped as smear layer present. Results: Group 1 showed inefficiency in removing smear layer with only 15% clean walls in middle one-third and no clean walls in apical one-third. Group 2 (NaOCl + EDTA) showed 55% clean walls in middle one-third while 15% clean walls in apical onethird while group 3 showed 70% effectiveness in middle onethird and only 15% effectiveness in apical one-third. Conclusion: EDTA and Nd:YAG were found more efficient in smear layer removal than saline. Results of EDTA and Nd:YAG were comparable in apical one-third while Nd:YAG was found to be more efficient than EDTA in middle one-third.