Details

Autor(en) / Beteiligte

• TOMITA, Fumihito
• NIWANO, Kazuaki
• KOTA, Kohichi
• OKIJI, Takashi

Titel

Analysis of Torque and Apical Forces during Root Canal Instrumentation with ProTaper : Comparison between Novice and Experienced Operators

Ist Teil von

• The Japanese Journal of Conservative Dentistry, 2007/10/31, Vol.50(5), pp.608-614

Ort / Verlag

The Japanese Society of Conservative Dentistry

Erscheinungsjahr

2007

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Proper operation of nickel titanium rotary instruments is very important to avoid iatrogenic events such as file separation and apical canal transportation. The aim of this study was to investigate physical parameters of proficiency for ProTaper instrumentation by means of real-time measurement of the torque and vertical forces exerted during instrumentation by novice and experienced operators. Seventy simulated canals with a 30-degree curvature in clear resin blocks were divided into two groups. Before the measurement, Group A was instrumented with the ProTaper system to a size SX until passive penetration stopped, and Group B was instrumented to a size F2 until the full working length was reached. Two endodontists (6 and 4 years of experience with ProTaper instrumentation) and five residents (no clinical experience of ProTaper instrumentation) then prepared the groups A and B with S1 and F3, respectively, to the full working length(n=5, each), and the torque and vertical forces were measured with a newly designed torque- and force-measuring device. As physical parameters, the force-time product, torque-time product and working time during the preparation were calculated. Moreover, the lengths of time lag between force and torque peaks were assessed. The results obtained were as follows: (1) Regarding the three physical parameters, significant differences between experienced and novice operators were not always detected due to great inter-operator variations among novice operators. (2) The time lag between force and torque peaks was always seen in experienced operators, whereas the time lag was often non-detectable or reversed in novice operators. (3) In experienced operators, the length of time lag for F3 was significantly longer than that for S1 (p<0.01, t-test). It was concluded that the time lag between force and torque peaks may be an indicator of operator proficiency. The longer time lag for F3 could be related to the separation of this instrument due to the delay in the release from high torque.