On comprehensive analysis of root canal shaping ability of three endodontic files of different kinematics.

Infection of the tooth's root canal requires what is called root canal treatment (RTC). The most important part of endodontic treatment is to shape the root canal and remove its infected portion using endodontic files of various protocols, kinematics and designs that suit the particular geometry. Cleaning and Shaping the canal efficiently remove the root canal bacterial biofilms or tissue remnants while keeping its natural geometry. The result is determined by shaping the ability of the relevant endodontic file. In the available literature, no norm has been established for the measurement of various endodontic files' ability to do effective shaping. We present in this study a method to analyse and measure the shaping ability of endodontic files of three different kinematics.

Effect of volumetric shrinkage of restorative materials on tooth structure: A finite element analysis.

Post-treatment coronal hermetic seal of the root canal opening prevents the food or saliva which assist to achieve successful endodontic treatment. Gutta-percha is filled in the inner canal, that is, from cervical third to apical third. Gutta-percha does not provide the hermetic seal because it does not bound with dentine walls. Various new restorative materials have been developed in the last 6-7 decade but drawback related to the polymerization shrinkage of the composite resin remains a clinical problem. In general, dental composites having volumetric shrinkage of the material depends on its formulation and curing conditions. In this article, the effect of this polymerization shrinkage on the tooth structure has been studied.

Force and vibration generated in apical direction by three endodontic files of different kinematics during simulated canal preparation: An in vitro analytical study.

During root canal shaping, pain could result from the high level of force or vibration generated. This could be related to file kinematics or geometry. In the present study, a comparison is made between forces and vibrations generated by endodontic files having three different kinematics. Square pillar resin blocks were used as simulated root canals to study forces and vibrations generated by the file having reciprocating motion (WaveOne Gold), transline motion (Self-Adjusting File), and rotary motion (2Shape). The forces and vibrations were measured using the dynamometer and accelerometer, respectively. Recorded time domain signals were processed in MATLAB to calculate the root mean square value. A one-way analysis of variance and Tukey's test for post hoc comparison at 95% confidence interval were applied over the root mean square data of different files. From a statistical analysis of the file systems, the null hypotheses could not be accepted (P < 0.05) as 95% of the confidence interval. Differences between the means were statistically significant. The root mean square values of force and vibration for WaveOne Gold significantly exceeded those of Self-Adjusting File, 2Shape1, and 2Shape2 while the root mean square values of vibration for 2Shape1 and 2Shape2 were significantly less than the Self-Adjusting File; however, the root mean square value of force for the 2Shape2 was significantly more than for the Self-Adjusting File. Under the present experimental conditions, significant differences in the root mean square values of force and vibration of the three endodontic files of different kinematics have been observed. The WaveOne Gold file system generated higher apical force and vibration than the transline and rotary file system.

Computer-aided design-based guided endodontic: A novel approach for root canal access cavity preparation.

In cases of teeth with unusual morphology like calcified pulp canal, guided endodontic treatment is suggested. An endodontic guide which navigates burs according to a preplanned path is used. Existing approaches of endodontic guide design are based on visual observation and analysis of tomographic scan of teeth. Hence, they are time-consuming and expert-dependent. Computer-aided design-based methodology was employed to design and fabricate a customized endodontic guide. A cone beam computed tomographic scan with MIMICS software was used to create a solid model of the teeth. The solid model generated was sliced through the developed program in MATLAB. The geometric centers of consecutive slices were joined to plot the root canals central axis. To gauge the optimum bur angulation for guide design, a straight line fitted in the data set of the geometric center helped create minimally invasive access. Methodology involved simulated verification of the drill path to judge the accuracy and feasibility of root canal access cavity preparation. Next, endodontic guides for extracted teeth were designed and fabricated using a three-dimensional printer, followed by guided root canal access cavity preparation for extracted teeth. To validate the proposed methodology, using a MATLAB image processing tool box, the deviation between the prepared root canal access cavity axis and root canal axis was analyzed in radiographs of post-treated teeth. The deviation between the tool path axis and root canal axis in simulated root canals was found to be not more than 0.210 ± 0.04 mm. The deviation between the axis of the planned root canal access cavity and the prepared root canal access cavity was 0.07 ± 0.02 mm. The proposed method reveals encouraging results for endodontic guide design.

Force and vibration correlation analysis in the self-adjusting file during root canal shaping: An in-vitro study.

BACKGROUND/PURPOSE: The focus of this study was to find a correlation between the forces and vibrations during root canal shaping. This can be used to predict the fracture of the self-adjusting file (SAF) in root canal shaping. MATERIALS AND METHODS: Forty J-shaped resin blocks were used in this study. Simulated root canals of resin blocks were prepared with the SAF. Force and vibration during root canal shaping were measured by dynamometer and accelerometer respectively. The recorded time domain signal of force and vibration were transformed to frequency domain signals. Frequency domain signals had been used for correlation study between force and vibration amplitude. The root mean square (RMS) value of force and vibration signature for new file and file just before failure were statistically compared using t-test at 95% confidence interval (CI). RESULTS: Vibrations generated during root canal shaping exhibited positive linear correlation (r = 0.9173) with force exerted by the SAF on the root canal. It means vibration has strong correlation with force. The RMS values of force and vibration increase significantly (P < 0.05) just before the fracture. CONCLUSION: From force and vibration analysis of SAF it was concluded that the vibration is well associated with force applied by the SAF on root canal. Therefore, the trend of force variation was reflected in the vibration signature. The sudden increment in vibration was the symptom of bulge formation and the end of useful life of the SAF.