2种根尖定位仪诊断牙根纵裂的实验研究

目的研究Root ZX和Raypex5根尖定位仪是否能诊断牙根纵裂的存在及其准确位置。方法将20颗离体的双根管单根前磨牙拔髓并扩挫至根尖孔，测量原始根管的实际长度。锤击放置在根管内的根充扩大器柄部使牙根形成纵裂，测量纵裂根管的实际长度，并用Root ZX和Raypex5根尖定位仪测量仅有纵裂线而未完全分裂的纵裂牙根管长度和完全分裂的纵裂牙根管长度，对2种根尖定位仪的根管电测值与实际根管长度进行比较。结果模拟的牙根纵裂均为颊舌向裂，而且裂隙均通过根尖孔。对于仅有纵裂线而未完全分裂的纵裂牙根，Root ZX和Raypex5不能探测到纵裂位置；对于完全分裂的纵裂牙根，Root ZX和Raypex5都能探测到纵裂位置，电测长度在纵裂根管实际长度±1.0 mm范围内分别为97.5%、100%。结论根尖定位仪对仅有纵裂线的牙根纵裂无诊断价值，但对完全纵裂的牙根却有较高的诊断准确性。

An in vitro study of two kinds of root apex Iocators to diagnose vertical root fracture

Objective To evaluate the accuracy of Root ZX and Raypex5 root apex locators in detecting vertical root fractures. Methods A total of 20 extracted bi-canal, single-root premolars were extirpated of pulp and expanded to root foramen. The actual length of root canal was measured. The root canal filling amplifier in root canal was hammered and root vertical fractures occurred. The actual length of vertical fracture root canal was measured. Root ZX and Raypex5 were used to measure the canal length in incomplete and complete vertical root fracture respectively. The lengths measured by two kinds of root apex locators were compared with actual canal length. Results All of the simulated vertical root fractures were buccal-lingual fissure through the apical foramen. To incomplete vertical root fracture, Root ZX and Raypex5 couldn′t detect the vertical root fracture. To complete vertical root fracture group, Root ZX and Raypex5 detected the vertical root fracture within ±1.0 mm in 97.5%, 100% respectively. Conclusion The root apex locator lacks of diagnostic value for incomplete vertical root fracture, but provides with preferable veracity for complete vertical root fracture.