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Curved molar root canal preparations using Hero 642 rotary nickel-titanium instruments
M F Bertrand1, L Lupi-Pégurier, E Médioni
1Department of Conservative Dentistry and Endodontics, University of Nice-Sophia Antipolis, France. mfbertra@unice.fr
International Endodontic Journal
|January 5, 2002
Summary
The Hero nickel-titanium rotary system better maintained the original shape of curved root canals in the apical third compared to stainless steel hand instruments. This rotary system reduced canal transportation during root canal preparation.
Area of Science:
- Endodontics
- Dental Materials Science
Background:
- Root canal curvature can complicate preparation.
- Nickel-titanium rotary systems offer potential advantages over traditional stainless steel instruments.
Purpose of the Study:
- To compare the shaping ability of the Hero 642 nickel-titanium rotary system versus stainless steel hand instruments in curved root canals.
- To evaluate root canal transportation and shape maintenance in different canal thirds.
Main Methods:
- The Bramante method was used on 24 human mandibular molars with >20-degree canal curvature.
- Canals were prepared using either stainless steel hand instruments (step-back) or the Hero 642 rotary system.
- Digital image analysis assessed dentine removal, shape factor, and canal center displacement in apical, middle, and coronal thirds.
Main Results:
- No significant differences in dentine removal or shape change were observed in the coronal and middle thirds.
- Significantly less canal transportation occurred in the apical third with the Hero system compared to hand instruments (P=0.0171).
Conclusions:
- The Hero nickel-titanium rotary system demonstrated superior maintenance of the original canal shape in the apical third of curved canals.
- The Hero system, used in a crown-down technique, resulted in less apical transportation than stainless steel hand instrumentation.