Comparison of Shaping Characteristics of Two Nickel-Titanium Rotary Instruments and a Stainless-Steel Hand Instrument in Oval Canals of Mandibular Premolars: An In Vitro Study

Abstract

Aim: To compare the cleaning and shaping effects of two rotary NiTi systems—ProTaper and Revo-S—with manual stainless-steel K-files in oval canals. Materials and methods: Thirty extracted mandibular premolars were mounted in acrylic molds and sectioned at 3 mm and 6 mm from the apex. Canal preparation was performed with K-files (Group I), ProTaper rotary files (Group II), and Revo-S rotary files (Group III). Canal shape and cleanliness were assessed by comparing pre- and post-instrumentation images using a transparent grid system. Data were analyzed with SPSS (p < 0.05). Results: Canal cleanliness was better at the 6 mm level than the 3 mm level. At the apical 3 mm, the cleaning efficiency ranked as follows: ProTaper > K-files > Revo-S. At the 6 mm level, the ranking was K-files > Revo-S > ProTaper. ProTaper also produced more regular canals at the apical 3 mm, while K-files resulted in the most regular canals at the 6 mm level. ProTaper preserved the original canal shape better than the other two groups at both levels. Conclusion: None of the techniques fully cleaned and shaped oval canals. The design and taper of the instruments significantly impacted canal shaping and cleanliness, with ProTaper being most effective at preserving canal shape and cleaning at both levels.