牙胶尖对机用镍钛器械预备弯曲根管的适应性评价

目的：评价牙胶尖对机用镍钛器械预备弯曲根管的适应性，探讨牙胶尖与弯曲根管壁适应性的最佳效果。方法：将塑料弯曲根管模型随机分为8组，其中4组为MTwo组、4组为Sendoline组，分别预备至0.06/20#、0.06/25#、0.04/35#、0.04/40#和0.04/20#、0.04/25#、0.04/30#、0.06/30#。单尖法充填根管，静置1周，将模型的根尖孔以上1、2、3、4和5 mm处垂直于模型长轴方向用慢速切割机横切，并用显微镜照相，绘图软件测量各截面牙胶尖的充填率和糊剂的最大宽度。结果：距根尖孔1 mm处，牙胶尖的充填率最小，越接近根尖口，充填率越大，距根尖孔5 mm处，各组根尖部充填率均为最大值。随号数的增大，牙胶尖充填率减小，糊剂的宽度增大；当根管预备的号数<30#时，各组牙胶尖充填率和糊剂宽度比较差异无统计学意义（P>0.05）；≥30#时，与0.04/30#组比较，0.04/35#组和0.04/40#组根尖部充填率减小（P<0.05）；与0.04/35#组比较，0.04/40#组根尖部充填率减小，在距根尖1和4 mm处差异有统计学意义（P<0.05），在距根尖2、3和5 mm处差异无统计学意义（P>0.05）。与0.04/30#组比较，0.04/35#组根尖部糊剂的宽度增大，在距根尖1、2和3 mm处差异无统计学意义（P>0.05），在距根尖4和5 mm处差异有统计学意义（P<0.05）；0.04/40#组根尖部糊剂的宽度增大，在距根尖1、2、4和5 mm处差异有统计学意义（P<0.05），在3 mm处差异无统计学意义（P>0.05）。与0.04/35#组比较，0.04/40#组根尖部糊剂的宽度增大，在距根尖1 mm处差异有统计学意义（P<0.05），在距根尖2、3、4和5 mm处差异无统计学意义（P>0.05）。0.04锥度组比0.06锥度组(相同号数)充填率大、根尖部糊剂的宽度小，但差异无统计学意义（P>0.05）。结论：根管预备终末号数<30# 时，牙胶尖对根管壁的适应性最佳，充填效果最好。

Evaluation of adaptability of gutta percha point to curved root canals prepared by rotatory nickel titanium instruments

Abstract:ObjectiveTo evaluate the adaptability of gutta percha point to curved root canals prepared by rotatory nickel titanium(NiTi)instruments,and to investigate the best effect of the adaptability of gutta percha point and the wall of curved root canals.Methods The plastic curved root canal models were randomly divided into 8 groups.Four groups were named MTwo group,and the other groups were named Sendoline group.They were respectively prepared to 0.06/20#,0.06/25#,0.04/35#,0.04/40#,and 004/20#,0.04/25#,0.04/30#,0.06/30#.All of these models were filled using the single-cone technique.After a week,the models were cutted from the apical foramen to 1,2,3,4,and 5 mm perpendicularly to the model with low speed diamond saw.Photographs were taken using microscope.The filling rates and the widths of the gutta percha point were measured by drawing software.Results The filling rates of gutta percha point were minimal at 1 mm section from the apical foramen.The closer it reached the apical foramen,the bigger the filling rates were seen.The filling rates in various groups at apical section were maximum at 5 mm section from the apical foraman.The filling rates were decreased and the widths of the gutta percha point were increased with the increasing of the number of gutta percha point.When the root canals were prepared to <30#,the filling rates and the widths had no significant differences (P>0.05).When the root canals were prepared to ≥30#,the filiing rates in 0.04/35# group and 0.04/40# group at apical section were decreased compared with 0.04/30# group(P<0.05).There were significant differences at 1 and 4 mm sections and there were no significant differences at 2,3,and 5 mm sections in 0.04/40# group compared with 0.04/35# group(P>0.05).The width of the gutta percha point at apical section of 0.04/35# group was increased compared with 0.04/30# group and there were no significant differences at 1,2,and 3 mm sections(P>0.05) and there were significant differences at 4 and 5 mm sections(P<0.05) between 0.04/30# group and 0.04/35# group.The width of the gutta percha point at apical section in 0.04/40# group was increased compared with 0.04/30# group and there was no significant difference at 3 mm section(P>0.05) and there were significant differences at 1,2,4,and 5 mm sections(P<0.05) between 0.04/30# group and 0.04/40# group.The width of the gutta percha point at apical section in 0.04/40# group was increased compared with 0.04/35# group and there was significant difference at 1 mm section(P<0.05) and there were no significant differences at 2,3,4 and 5 mm sections(P>0.05) between 0.04/35# group and 0.04/40# group.Compared with 0.06 taper groups with the same number，the gutta percha point in 0.04 taper groups had bigger filling rates and smaller widths,but there were no significant differences between them(P>0.05).Conclusion When the root canals are prepared to <30#,the adaptability of gutta percha point to curved root canals is the best,and the filling effect is the best.