title: [Application of sonic endo-instruments in combination with Mtwo Ni-Ti files in root canal preparation of molars].
abstract: OBJECTIVE
  To evaluate the clinical outcome of sonic endo-instruments in combination with Mtwo Ni-Ti files in root canal preparation of molars.
  
  
  METHODS
  One hundred patients (118 first molars, 428 root canals) were included in this study, they were randomly assigned into 2 groups (n=50).Group 1 was shaped with sonic endo-instruments in combination with Mtwo Ni-Ti files,while group 2 was treated with stainless-steel files, both groups were obturated with lateral condensation technique. The time of root canal shaping, acute post-operative pain, the quality of the root canal filling and the success rate after 1 year were recorded and analyzed using SPSS 11.0 software package.
  
  
  RESULTS
  The average preparation time in group 1 was (5.3±0.6)min/canal and (12.7±0.9) min/canal in group 2 (t=100.89,P<0.001). The rate of acute postoperative pain was significantly lower X(2)=4.87, P<0.05,in group 1 (8.20%) than in group 2 (22.81%); in group 1, 92.86% root canals were filled adequately while only 78.92% in group 2, the difference was significant (X(2)=17.45, P<0.05);higher success rate (X(2)=3.95, P<0.05) after 1 year was achieved in group 1 (91.80%) compared with group 2 (78.95%).
  
  
  CONCLUSIONS
  Compared with stainless-steel files, sonic endo instruments in combination with Mtwo Ni-Ti files in root canal preparation of molars seem more effective, cause less postoperative pain and offer higher success rates.
authors.affiliation: Department of Stomatology, Fujian Provincial Hospital. Fuzhou 350001,Fujian Province, China.E-mail:751310330@qq.com.
authors.forename: Zhan-hong
authors.initials: ZH
authors.lastname: Chen
mesh_terms: D000368:Aged; D003786:Dental Pulp Cavity; D006801:Humans; D008963:Molar; D009532:Nickel; D010149:Postoperative Pain; D018915:Root Canal Preparation; D012390:Root Canal Therapy; D013193:Stainless Steel; D014025:Titanium
chemical_list: C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium