Root Canal Preparation of Mandibular Molars with 3 Nickel-Titanium Rotary Instruments: A Micro–Computed Tomographic Study

By Zhao D, Shen Y, Peng B, Haapasalo M.

Date: 01/2015
Journal: JOE


Purpose: To quantitatively assess canal preparation outcomes achieved by the single-file WaveOne technique under reciprocating movement, the ProTaper Next  technique, and conventional ProTaper Universal instruments with continuous rotation.


•N= 36 maxillary first molars with 2 separate mesial canals and 1 distal canal.

•Teeth were scanned preoperatively and postoperatively using micro-CT scanning with a voxel size of 30 𝞵m.

•Canals were prepared with PTU, PTN, and WaveOne systems under hypochlorite irrigation.

•The volume of the untreated canal; the volume of dentin removed after preparation; the amount of the uninstrumented area; and the transportation to the coronal, middle, and apical thirds of canals were measured.

•The preparation time and instrument failure were recorded.

Most highlighted Results: 

-Instrumentation of canals increased their volume and surface area.

-The distal canals had a significantly higher proportion of unprepared surfaces than mesial canals.

-The PTN system produced less transportation than the WaveOne and PTU systems in the apical third of the mesial canals (Sig.).

-There was no significant difference on apical transportation in distal canals among the 3 instrument systems.

-Instrumentation with Wave- One was significantly faster than with the other 2 instruments.

Clinical significance:

In curved canals, using PTN might result in less apical transportation compared to PTU and WaveOne systems.