目的: 研究不同根管内容物对口腔颌面锥形束CT(cone-beam computed tomography，CBCT)诊断牙根纵裂(vertical root fracture，VRF)准确性的影响。方法: 选择因正畸治疗或牙周病而拔除的结构完整的单根管干燥离体牙24颗，沿釉牙骨质界去除牙冠，进行根管和桩道预备后制备为研究样本。将24个样本分为两组，每组12个。A组为对照组(无VRF组)，根据根管内容物分为5个亚组：空白组、纤维桩组、牙胶尖组、钛桩组和金钯桩组；B组为实验组(VRF组)，亚组分组同上。VRF组使用统一方法制备为VRF模型，以专用根管钉使牙根发生颊舌向完全裂开后再粘接复位；对照组不进行模拟VRF的操作。钛桩和金钯桩根据根管预备情况个性制作，通过X线检查确认桩与根管壁的密合性。所有样本均置于猪下颌骨牙槽窝中进行CBCT扫描，由经验丰富的牙体牙髓病学专科医师和口腔颌面医学影像学专科医师进行盲法判读，统计分析诊断准确率。结果: 空白组、纤维桩组、牙胶尖组、钛桩组、金钯桩组中VRF的诊断准确率依次为95.83%、91.67%、87.50%、79.17%和45.83%，与空白组相比，纤维桩组(P>0.999)、牙胶尖组(P=0.500)和钛桩组(P=0.125)的诊断准确率差异均无统计学意义。金钯桩组中VRF诊断准确率最低，与其他各组相比差异均有统计学意义(P < 0.001)。结论: 不同根管内容物在CBCT中的伪影对VRF诊断的准确性产生不同程度的影响，纤维桩、牙胶尖和钛桩的影响较小，而金钯桩影响较显著。

Objective: To study the effect of various intracanal materials on the accuracy of oral maxillofacial cone-beam computed tomography (CBCT) for the diagnosis of vertical root fracture (VRF). Methods: A total of twenty-four structurally intact single root canal dried and isolated teeth extracted for orthodontic treatment or periodontal disease were collected. The teeth were decrowned along the cemento-enamel junction (CEJ) and then used as samples for the study after conventional root canal preparation and post preparation. The 24 samples were divided into two groups with 12 samples in each group. Group A was the control group (no VRF group). According to intracanal materials, they were divided into five subgroups: blank group, fiber post group, gutta-percha point group, titanium post group and gold-palladium post group. Group B was the experimental group (VRF group), and subgroups were grouped as above. The VRF model was prepared by a unified method in the VRF group: the root was completely fractured in the buccolingual direction with a custom root canal nail and then cemented and reset. The control group was not subjected to the simulation of VRF. Titanium post and gold-palladium post were made according to the individuality of the root canal preparation, and the tightness of the post to the root canal wall was confirmed by X-ray radiograph. Then all the samples were scanned by CBCT in the isolate swine mandibular alveolar sockets. The diagnostic accuracy was statistically analyzed via blind interpretation by experienced endodontic specialists and oral and maxillofacial medical imaging specialists. Results: The accuracy of the diagnosis of VRF in the blank group, fiber post group, gutta-percha point group, titanium post group, and gold-palladium post group in CBCT was 95.83%, 91.67%, 87.50%, 79.17%, and 45.83%, respectively. Compared with the blank group, the differences were not statistically significant in the fiber post group (P>0.999), the gutta-percha point group (P=0.500) and the titanium post group (P=0.125). The lowest diagnostic accuracy of VRF was found in the gold-palladium post group, and the difference was statistically significant compared with all other groups (P < 0.001). Conclusion: Various intracanal materials have different degrees of influence on the diagnostic accuracy of VRF diagnosis in CBCT. The influence of fiber post, gutta-percha point and titanium post was small, while the influence of gold-palladium post was significant.