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Comparative Evaluation of Dentinal Crack Formation Using Three Ni-Ti Rotary Systems after Root Canal Preparation: An
Kaveh Nasiri1, Maya Doychinova2, Karl-Thomas Wrbas3
1Independent Researcher, Essen, Germany, Phone: +49 16095534189, e-mail: DDS.Nasiri@web.de, Orcid: https://orcid.org/0000-0001-5571-0550.
The Journal of Contemporary Dental Practice
|October 4, 2025
Summary
This study found that ProTaper Next (PTN) and 2Shape rotary systems caused fewer dentinal cracks during root canal preparation compared to the Reciproc system. Reciproc showed a more destructive effect, especially in the apical third.
Area of Science:
- Endodontics
- Dental Materials Science
- Biomaterials Engineering
Background:
- Root canal preparation aims to clean and shape the root canal system.
- Nickel-titanium (Ni-Ti) rotary systems are widely used for root canal preparation.
- Dentinal defects, such as cracks, can compromise the long-term success of endodontic treatment.
Purpose of the Study:
- To compare the incidence of dentinal defect formation following root canal preparation with three different Ni-Ti rotary systems: ProTaper Next (PTN), 2Shape, and Reciproc.
- To evaluate the safety and potential risks associated with each system in terms of inducing cracks.
Main Methods:
- Sixty extracted first mandibular molars with two separated canals were selected.
- Samples were divided into four groups: Control (unprepared), PTN, 2Shape, and Reciproc (n=15 each).
- Root canal preparation was performed using the specified rotary systems. Samples were sectioned at 3, 6, and 9 mm from the apex and examined under a stereomicroscope for dentinal defects. Statistical analysis was performed using Chi-square and Fisher's exact tests.
Main Results:
- No dentinal cracks were observed in the control group.
- The Reciproc group exhibited the highest incidence of cracks (40%), followed by ProTaper Next (24%) and 2Shape (11%).
- Significantly more cracks were detected at the 3 mm apical level for the Reciproc system (p < 0.05). No significant differences were found at 6 and 9 mm levels.
Conclusions:
- All tested rotary file systems have the potential to induce dentinal cracks, particularly in the apical third of the root canal.
- The Reciproc system demonstrated a more detrimental effect on dentinal integrity compared to ProTaper Next and 2Shape.
- ProTaper Next and 2Shape appear to be safer alternatives for root canal preparation in the mesial roots of first mandibular molars, minimizing the risk of crack formation.
