Micro-computed tomographic evaluation of the shaping ability of three nickel-titanium rotary systems in the middle mesial canal of mandibular first molars: an ex vivo study based on 3D printed tooth replicas.

"Declarations Ethics approval and consent to participateThe human mandibular first molars used in this study were obtained from the Department of Dentistry, Ninth People’s Hospital of Suzhou. All methods have been performed in accordance with the Declaration of Helsinki and have been approved by the Ethics Committee of Ninth People’s Hospital of Suzhou with the approval number # KY2022-089-01. Informed consent was obtained from all subjects and/or their legal guardian(s). Consent for publicationNot applicable. Competing interestsThe authors declare no competing interests. Competing interests The authors declare no competing interests."

"Funding This study was funded by Suzhou “Medical Health Science and Technology Innovation” Project (SKY2022030), and Scientific Project of Ninth People’s Hospital (YK202215, YK202323)."