三种镍钛机动器械预备后牙弯曲根管的成形效果

目的　研究 3种镍钛机动系统预备后牙弯曲根管的成形效果。方法　选择离体下颌磨牙近中弯曲根管 64个 ,包埋于Branmante模型中 ,随机分为 4组 :①Flexofile;②LightSpeed;③ProFile ;④QantecSC。根管预备至 30号器械 (主尖锉 ) ,分析各组的牙本质切削面积、根管壁最小厚度和根管中心偏移。结果　Flexofile组在根尖区和根中段 ,牙本质切削面积和根管中心的偏移均为最大 ,与LightSpeed和ProFile组间的差异具有显著性 (P <0 0 5) ,QantecSC在根尖区有过度切削 ;根中段远中侧的牙本质最小厚度在Flexofile组为最小 ,与LightSpeed组间的差异具有非常显著性 (P <0 0 1 ) ;在根中段 ,Flexofile组中 87%的根管中心移向远中侧 ,镍钛各组中 ,仅 1 /3的根管中心移向远中。结论Flexofile预备弯曲根管 ,根尖和根中段成形不良 ,使用LightSpeed和ProFile则可获得良好的成形

The shaping effects of three nickel-titanium rotary instruments on preparing curved canals in posterior teeth

OBJECTIVE: To investigate the shaping effects of three nickel-titanium rotary instruments on preparing curved canals in posterior teeth. METHODS: 64 curved mesial canals of extracted lower molars, embedded in the Branmante models, were randomly assigned to four groups: (1) Flexofile; (2) LightSpeed; (3) ProFile; (4) Qantec SC. Apical preparation was carried out till size 30. The area of dentine removal, least remaining dentine thickness and transportation of canal center were measured. RESULTS: Flexofile resulted in more dentine removal and canal center transportation than LightSpeed and ProFile (P < 0.05) at the apical and mid-root levels. In the mid-root sections, Flexofile left the thinnest dental wall in the distal aspect; 87% of the canal centers in the Flexofile group were transported in a distal direction as compared with one third in other groups. CONCLUSIONS: LightSpeed and ProFile exhibited better shaping ability than Flexofile in preparing curved canals.