ProTaper rotary root canal preparation: assessment of torque and force in relation to canal anatomy.

AIM To investigate physical parameters for ProTaper nickel-titanium (NiTi) rotary instruments whilst preparing curved canals in maxillary molars in vitro. METHODOLOGY A novel torque-testing platform was used to prepare root canals in 15 extracted human maxillary molars with ProTaper rotary instruments. Peak torque and force was registered along with numbers of rotations required to shape the canals. Canals were divided into 'wide' and 'constricted' groups depending on canal volumes assessed by micro computed tomography. Mean scores for each instrument type were calculated and statistically compared using anova and Scheffé posthoc tests. RESULTS Mean torque varied between 0.8 +/- 0.5 and 2.2 +/- 1.4 N cm whilst mean force ranged from 4.6 +/- 2.6 to 6.2 +/- 2.7 N. Mean numbers of rotations totalled up to 21. All three variables registered were significantly correlated to preoperative canal volumes (P < 0.001) and differed significantly between 'wide' and 'constricted' canals (P < 0.001). CONCLUSIONS Whilst high forces were used in some cases, no ProTaper instrument fractured when a patent glide path was present. There were significant positive correlations between canal geometry and physical parameters during shaping.

[1]  E. Verdes,et al.  The effect of root canal morphology on canal shape following instrumentation using different techniques. , 1997, International endodontic journal.

[2]  F. Barbakow,et al.  The 'Lightspeed' preparation technique evaluated by Swiss clinicians after attending continuing education courses. , 1997, International endodontic journal.

[3]  Geoff Bateman,et al.  Dynamic and cyclic fatigue of engine-driven rotary nickel-titanium endodontic instruments. , 1999 .

[4]  Jean-Paul Micallef,et al.  Location of contact areas on rotary Profile1 instruments in relationship to the forces developed during mechanical preparation on extracted teeth , 1999 .

[5]  G. Bateman,et al.  A new method for the quantitative analysis of endodontic microleakage. , 1999, Journal of endodontics.

[6]  J Y Blum,et al.  Analysis of forces developed during mechanical preparation of extracted teeth using Profile NiTi rotary instruments. , 1999, International endodontic journal.

[7]  B. Sattapan,et al.  Defects in rotary nickel-titanium files after clinical use. , 2000, Journal of endodontics.

[8]  H H Messer,et al.  Torque during canal instrumentation using rotary nickel-titanium files. , 2000, Journal of endodontics.

[9]  P. Rüegsegger,et al.  Three-dimensional Analysis of Root Canal Geometry by High-resolution Computed Tomography , 2000, Journal of dental research.

[10]  G Gambarini,et al.  Rationale for the use of low-torque endodontic motors in root canal instrumentation. , 2000, Endodontics & dental traumatology.

[11]  O A Peters,et al.  Effects of four Ni-Ti preparation techniques on root canal geometry assessed by micro computed tomography. , 2001, International endodontic journal.

[12]  G Gambarini,et al.  Cyclic fatigue of ProFile rotary instruments after prolonged clinical use. , 2001, International endodontic journal.

[13]  P Machtou,et al.  Failure of ProFile instruments used with high and low torque motors. , 2001, International endodontic journal.

[14]  G. Yared,et al.  Influence of rotational speed, torque and operator proficiency on failure of Greater Taper files. , 2002, International endodontic journal.

[15]  O A Peters,et al.  Dynamic torque and apical forces of ProFile.04 rotary instruments during preparation of curved canals. , 2002, International endodontic journal.