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目的研究三种机用镍钛器械对根尖孔偏离及未偏离解剖根尖顶的根管超工作长度1mm进行预备,观察并分析根尖孔发生偏移的方向、频率和程度,为根尖孔偏离解剖根尖顶与否对根管预备后根尖孔偏移的影响提供理论依据。方法选取因牙周病拔除的120颗离体单根牙,分为A、B两组各60颗牙:根尖孔偏离解剖根尖顶组为A组,根尖孔在解剖根尖顶组为B组,A、B两组再各分为3组分别是:T组(TF组)、P组(Protaper组)、K组(K3组)。根管预备前经扫描电镜拍摄术前片,记录初始根尖孔的表面形态,然后用上述三种锉对A,B组标本分别进行超工作长度(WL+1mm)根管预备,术后再次拍摄根尖孔表面形态,评价根管预备后根尖孔偏移的方向、频率和程度。结果经三种不同镍钛锉超工作长度(WL+1mm)根管预备后,无论原始根尖孔是否偏离解剖根尖顶,标本有85.83%的根尖孔发生了不同方向不同程度的根尖偏移。具体表现为:根尖孔偏移发生率A组较B组高,两组中均为K组较T组高,且差异均有统计学意义(P<0.05)。根尖孔偏移程度也存在这类似的差异,K组高于T组,且K组相对容易产生严重程度(2、3级)的根尖孔偏移,经秩和检验此差异有统计学意义(P<0.05)。结论 TF、K3、Protaper三种机用镍钛旋转器械在超工作长度根管预备时由于器械超根尖止点工作可导致根尖孔偏移发生,尤其当根尖孔偏离根尖顶时,根尖偏移的程度加重。TF锉与Protaper锉、K3锉相比较在减少根尖孔偏移发生率及程度方面更具优越性。
Objective To study the preparation of three kinds of machine nickel-titanium instruments which deviate from the apical foramen and do not deviate from the root canal of the apical spine. The direction, frequency and degree of apical fissure were observed and analyzed. Deviation from the anatomical apical apex or not after root canal preparation of apical foramen offset to provide a theoretical basis. Methods A total of 120 single teeth extracted from periodontal disease were selected and divided into 60 teeth in group A and group B. The apical foramen deviated from the group of the apical vertebrae in group A and the apical foramina in group B Groups A and B were further divided into three groups: T group (TF group), P group (Protaper group) and K group (K3 group). Before the preparation of the root canal, the preoperative films were taken by scanning electron microscopy and the surface morphology of the initial apical foramen was recorded. Then, the superficial length (WL + 1mm) root canal preparation was performed on the A and B groups respectively with the above three files. The surface morphology of apical foramen was photographed, and the direction, frequency and degree of apical foramen offset after root canal preparation were evaluated. Results After three types of root canal preparation, the root apical foramina of 85.83% of the apical foramen of the specimens had different degrees of apical deviations shift. Specifically, the incidence of apical foramina was higher in group A than in group B, and K in both groups was higher than that in group T, and the difference was statistically significant (P <0.05). There were also similar differences in apical foramina shift, K group was higher than T group, and K group was relatively easy to produce serious degree (2,3 level) of apical foramina. This difference was statistically significant Significance (P <0.05). Conclusion TF, K3, Protaper three kinds of nickel-titanium rotary instruments in the preparation of super-working-length root canal due to super-apex tip device can lead to the occurrence of apical foramina shift, especially when the apical foramen deviates from the apex, root The degree of sharp offset increases. TF file and Protaper file, K3 file compared to reduce the incidence and extent of apical foramen offset more advantages.