A comparison of two nickel-titanium instrumentation techniques in teeth using microcomputed tomography

Aim The aim of the study was to compare the shaping of root canals by two nice-titanium instrumentation techniques using microcomputed tomography (MCT). Methodology Ten mandibular first molar teeth (30 canals) that had intact crowns and fully formed roots were scanned using MCT. Fifteen canals were instrumented using NiTiFlex hand files (Maillefer) using balanced force. The remainder were instrumented using prototype Profile 0.04 Taper instruments (Dentsply) in a crown-down manner to an apical size ISO 25. The teeth were scanned again following instrumentation. The two instrumentation techniques were compared in a total of 27 canals. The area of dentine removed at predetermined levels (2.0, 3.0, 4.5, 6,0, 7.5 mm) from the apex was measured. Transportation and centring were recorded. Images constructed at these levels were compared with video images of equivalent physical sections created after the second scan, The volume of dentine removed in the apical 7.5 mm of the root canals of each tooth was calculated and the different techniques compared. Rendered three-dimensional images were used to assess the preparations qualitatively. The time taken for preparation was recorded. Results There was no significant difference between hand instrumentation with NitiFlex files and machine instrumentation with prototype Profile 0.04 Taper instruments for any of the variables tested. Conclusions Both techniques produced well centred and tapered preparations.