Light emitting diode assessment of dentinal microcracks after root canal preparation with 4 different heat-treated file systems.

BACKGROUND: The purpose of this research was to evaluate the dentinal microcracks formation after root canal preparation with Hyflex® EDM ([electrical discharge machining], Coltene; Altstätten, Switzerland), Neolix Neoniti A1 EDM (Neolix; Beijing, China), Wave One Gold (Dentsply Sirona; York, PA, USA) and Edge File® X1 (EdgeEndo; Albuquerque, NM, USA) under illumination and magnification. METHODS: One hundred fifty mandibular molars with 2 different mesial canals extracted for periodontal reasons were included in the study. The samples were decoronated at 15 mm from the apex using a carborundum disc under copious water cooling. Access opening was done using a round bur. Sectioning of the distal root was done. Patency of mesial canals were checked using a 10 K file. The samples were randomly divided into 5 groups using simple randomization technique: group 1 (uninstrumented group); group 2 (Hyflex® EDM [HEDM] [Coltene]); group 3 (Neolix Neoniti A1 [NA1] [Neolix]); group 4 (Wave One Gold [WOG] [Dentsply Sirona]); and group 5 (Edge File® X1 [EFX] [EdgeEndo]). Biomechanical preparation in all groups was done following the manufacturer's instructions. Sectioning was done at 3 mm, 6 mm, and 9 mm from the apex using a 0.13 mm circular saw under copious water cooling. Sections were observed at 16× magnification under the dental operating microscope and illumination using a light emitting diode (LED) curing light. The χ2 test was used to determine the statistically significant differences at P<0.05. Intergroup comparison was done by the post-hoc Tukey test. RESULTS: Total of 1800 images were analyzed. The highest number of cracks was seen in Neoniti A1 group (43.33%) while the least number of cracks were seen with Wave One Gold group (13.33%). There was statistically difference between reciprocating groups and the rotary group. CONCLUSIONS: Within the limitations of this study, it can be concluded that all the heat-treated file systems produced dentinal microcracks. Rotary group (NA1 and HEDM) produced significantly more cracks than reciprocation group (WOG and EFX).

Management of intrinsic discoloration using walking bleach technique in maxillary central incisors.

INTRODUCTION: Non-vital bleaching is a non-invasive technique to treat the intrinsic discoloration of teeth of several etiologies. Hydrogen peroxide and sodium perborate are commonly used bleaching agents. AIM: The aim of this case report is to demonstrate the non-vital bleaching technique in maxillary anterior teeth. METHOD: Maxillary central incisors were isolated with rubber dam and root canal treatment was performed. Barrier space preparation was done using a heated instrument. Glass ionomer cement was used a barrier material. Mixture of hydrogen peroxide and sodium perborate was placed in the canal and sealed with intermediate restorative material. After 1 week, the procedure was repeated to achieve the desired results. CONCLUSION: Non-vital bleaching is a minimally invasive procedure to restore the esthetics of a discolored non-vital tooth. However, care should be taken to prevent any post-operative complications.