INCIDENCE OF APICAL ROOT CRACK FORMATION AFTER ROTARY ROOT CANAL INSTRUMENTATION AT DIFFERENT INSTRUMENTATION LENGTHS USING PROTAPER UNIVERSAL, PROTAPER NEXT AND PROTAPER GOLD FILES - AN IN-VITRO STUDY

Aim: To evaluate the incidence of apical root crack formation after canal preparation using ProTaper Universal (PTU), Next (PTN) and Gold (PTG) rotary file systems compare at various instrumentation lengths. Subjects Methods: One hundred single rooted extracted mandibular premolar teeth were mounted in acrylic resin blocks simulating periodontal ligament. The divided into four groups. Group I was instrumented PTU, group II PTN III PTG files, while IV left untreated, serving as a negative control group. Each subdivided three subgroups: A, B C till length (RCL), RCL-1 RCL+1. Root apex sectioned horizontally 1-2mm from foramen stained with 1% methylene blue dye followed by stereomicroscopic evaluation to determine cracks. data analyzed chi-square, Shapiro Wilkinson Cramers phi test. significance level set P<0.05. Result: Significant difference seen percentage cracks PTU PTG, no significant PTN. Specimen upto showed less compared those RCL Conclusion: produced least number PTU. Moreover, reduced formation.