Wang Yunxiao, Fan Wei, Wu Yanru, Sun Hualing, Zhang Yufeng
State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, 430079, People's Republic of China.
Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.
Clin Oral Investig. 2025 May 31;29(6):321. doi: 10.1007/s00784-025-06412-3.
This study investigated the distribution of nickel elements in root canals after root canal preparation using five different nickel-titanium instruments, as well as its cytotoxicity on dental pulp cells.
Root canal preparations were performed on extracted dental slices using five nickel-titanium instruments. The distribution of nickel within the root canal was analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Field Emission Electron Probe Micro-Analyzer (EPMA). Surface changes of new and reused instruments were examined by Scanning Electron Microscopy (SEM). Conditioned medium from prepared tooth slices was used to culture dental pulp cells, with cell proliferation assessed via the CCK-8 assay and morphology observed under a light microscope.
No significant increase in nickel residue was observed after seven consecutive preparations with the same instrument. However, elemental nickel residue was significantly higher in the apical parts compared to the middle and coronal parts intra-canal. The Reciproc Blue (RB) system showed notably higher nickel residues in the apical area. Surface wear was observed on the instruments after use. The conditioned medium did not significantly affect the morphology or proliferation of cultured pulp cells.
Nickel residues did not increase significantly with repeated use of the same instruments. All instruments showed higher residue in the apical parts, with the RB system exhibiting the highest levels. There were no significant changes in the instrument morphology after preparation. The use of five nickel-titanium instruments did not negatively affect the proliferation of dental pulp cells. However, the cumulative impact of nickel on cytotoxic effects requires further investigation.
This study revealed the distribution of nickel residues in the root canals after root canal instrumentation, in addition to providing an informative reference about the potential effects of nickel-titanium instruments on the results of regenerative endodontic therapy.
本研究调查了使用五种不同镍钛器械进行根管预备后根管内镍元素的分布情况，以及其对牙髓细胞的细胞毒性。
使用五种镍钛器械对拔除的牙片进行根管预备。采用电感耦合等离子体质谱法（ICP-MS）和场发射电子探针微分析仪（EPMA）分析根管内镍的分布。通过扫描电子显微镜（SEM）检查新器械和重复使用器械的表面变化。用制备好的牙片的条件培养基培养牙髓细胞，通过CCK-8法评估细胞增殖情况，并在光学显微镜下观察细胞形态。
同一器械连续使用七次后，镍残留量未见显著增加。然而，根管内根尖部位的镍元素残留量明显高于中部和冠部。Reciproc Blue（RB）系统在根尖区域的镍残留量明显更高。器械使用后观察到表面磨损。条件培养基对培养的牙髓细胞的形态或增殖没有显著影响。
同一器械重复使用时，镍残留量没有显著增加。所有器械在根尖部位的残留量都较高，RB系统的残留量最高。预备后器械形态无明显变化。使用五种镍钛器械对牙髓细胞的增殖没有负面影响。然而，镍对细胞毒性的累积影响需要进一步研究。
本研究揭示了根管治疗后根管内镍残留的分布情况，此外还为镍钛器械对牙髓再生治疗结果的潜在影响提供了有益参考。
