Basic And Clinical Study Of Overall Length Root Canal Preparation

ObjectiveThe purpose of this study was to explore the clinical application value of the full length preparation of root canal in micro apical surgery by detecting the tightness of the root tip after filling the full length preparation of root canal（preparation to anatomic apical foramen）and evaluating its efficacy after clinical micro apical surgery.MethodsOne hundred extracted single-rooted anterior teeth were selected for the study.These teeth were then randomly divided into group A₁、A₂、B₁、B₂、B₃（n=20）.Under the microscope,all of the root canals were prepared by mechanical protaper and the unified power（Ultrasonic 4 gear）was used for ultrasonic washing.Then,Conventional root canal preparation were conducted in group A₁、B₁and B₃（anatomical apical foramen retreated 1mm）,overall length root canal prepared in group A₂ and B₂.The GuttaFlow?2 room temperature flow tooth rubber combined with single gutta-percha cone filled in group A₁ and A₂;the thermoplasticized gutta-percha filled in group B₁、B₂ and B₃;root-end filling with MTA after thermoplasticized gutta-percha filled in group B₃.Then the filling effect were evaluated by the X-ray.Then Indian ink was dyed.After making transparent teeth,the root was rotated under a dental microscope（×10）to observe the penetration depth of dye in each tooth.The end of apical filling material was taken as the starting point to infiltrate into the ink insertion point in the root canal.The maximum length of staining was selected.Then used Image J to measure the length of three times and recorded the average value.68 patients（92 teeth）with obvious periapical destructive bone lesions（the diameter of the lesion was larger than 1.0 cm）were selected.They were randomly divided into the experimental group（48 teeth）and the control group（44 teeth）,34patients in each group.In the experimental group,the GuttaFlow?2 was filled after the root canal length preparation and simultaneously combined with apical curettage.In the control group,simultaneously filled root-end with MTA after thermoplasticized gutta-percha filling with conventional root canal preparation.During the follow-up period at 3,6,12 months postoperatively,evaluated of the prognosis by clinical symptoms and X-ray examination.ResultThe penetration depth of the dye solution of the five groups were A₁（1.79±0.37）mm、A₂（0.89±0.12）mm、B₁（3.44±0.65）mm、B₂（1.95±0.27）mm、B₃（0.84±0.19）mm.There were significant differences among the group A₁、A₂、B₁and B₂（F=121.656,P<0.05）;and there were significant difference between group A_l and A₂（t=7.414,P<0.05）、group B₁ and B₂（t=11.028,P<0.05）、group A_l and B₁（t=10.954,P<0.05）and group A₂ and B₂（t=11.673,P<0.05）.There were not significant differences among the results of the group A₁ and B₂（t=1.177,P>0.05）and group A₂ and B₃（t=0.494,P>0.05）.After 1 week,in the experimental group,there were 39 cases of grade 0 pain（39/48）and 9 cases of grade 1 pain（9/48）.In the control group,there were 40 cases of grade 0 pain（40/44）and 4 cases of grade 1 pain（4/44）.There were no statistically significant differences of postoperative pain response in the 2 groups（P=0.237>0.05）.After 6 months,in the experimental group,25 patients were cured and 23patients were improved.The success rate was 100%（48/48）.In the control group,23patients were cured and 21 patients were improved,the success rate was 100%（44/44）.The cure rate of experimental group was higher than that of the control group,but no statistical significant differences（P=0.406>0.05）were found in the two groups on the short-term clinical efficacy.After 1 year,in the experimental group,38 patients were cured and 10patients were improved.The success rate was 100%（48/48）.In the control group,27patients were cured and 17 patients were improved,the success rate was 100%（44/44）.The cure rate of control group was higher than that of the control group,but no statistical significant differences（P=0.071>0.05）were found in the two groups on the short-term clinical efficacy.Conclusion1.The root canal length preparation can achieve better apical sealing than conventional root canal preparation.2.The GuttaFlow?2 filling has a better apical sealing than the thermoplasticized gutta-percha filling.3.In clinical application,the curative effect of GuttaFlow?2 filling after the root canal length preparation and simultaneously combined with apical curettage is similar to the root-end filling with MTA after thermoplasticized gutta-percha filling with conventional root canal preparation.