Aim: This study was done to evaluate the efficacy of rotary and reciprocating endodontic instruments in maintaining the root canal anatomy during instrumentation procedure. Methodology: Forty human single-rooted mandibular premolars extracted for orthodontic reasons were used. Teeth were decoronated, access cavities were made, working length was determined and samples were subjected to Pre-instrumentation Cone Beam Computed Tomography (CBCT) scanning. The samples were randomly divided into two groups (n=20): Group 1: Wave-One (WO) reciprocating system and Group 2: ProTaperNext (PTN). The samples were prepared with these two systems and post instrumentation scans were performed.Pre and post instrumentation scans were compared to determine the canal-centering ratio at 0mm, 3mm and 5mm from canal orifice, apical transportation, and remaining dentin thickness (RDT) at 3,5 and 7mm from the root apex using Planmeca Romexis software.For statistical analysis, Shapiro Wilk test, paired t test, one way ANOVA and post hoc Tukey’s test were used. Results: -Results showed that group 1 (WO) had better centering ability at all three levels (at orifice 0.75; at 3mm 0.62; at 5mm 0.65) than group 2 (PTN) (at orifice 0.65; at 3mm 0.54; at 5mm 0.47). apical transportation was minimum with WO (0.056) than PTN (0.113). It was also observed that WO preserved dentin better than (RDT at 3mm .062; at 5mm .104; at 7mm .107) than PTN (at 3mm .062; at 5mm .104; at 7mm .107). Conclusion: WO showed better canalcentering ability with lesser canal transportation and more dentin remaining peripherally thanPTN.