Research On The Filing Motion And The Filing Force Prediction Of Tooth Root Canal Preparation

Root canal preparation is the most important process in root canal therapy,and its diagnosis and treatment effects determine the success of root canal therapy.Studies have shown that different motion have a crucial effect on root canal preparation and the service life of nickel-titanium instruments.At the same time,the filing force of root canal preparation has a greater impact on the fracture of nickel-titanium instruments.And research root canal preparation filing motion and filing force prediction are of great significance to the success of root canal therapy.This article focuses on shaping ability with different filing motion in root canal preparation,anti-fatigue characteristics of Nickel-Titanium files in different filing motion,and filing force prediction model in root canal preparation.The main work is as follows:Research the shaping ability with different filing motion in root canal preparation,change in the working length,central axis offset,curvature variation and preparation time and success rate were used as evaluation parameters.A computerized numerical control(CNC)machine was used to study the root canal preparation shaping ability of three different filing motions such as vertical downward motion,reciprocating up and down motion and spiral up and down motion,and compared with manual operation as a control group.And study the root canal preparation shaping ability of five different filing insertion angle such as-10 degrees,-5 degrees,0 degrees,5 degrees,and 10 degrees.The results show that using a spiral up and down motion,with 5 degrees of insertion angle,it has higher efficiency and better root canal preparation shaping ability than other motion methods.Research the anti-fatigue characteristics of Nickel-Titanium files in different file motion,the time for separation of nickel-titanium files was an evaluation parameters.The bone distal tibia of a cow was used as the material to prepare the bone simulative root canal.A computerized numerical control(CNC)machine was used to study the anti-fatigue characteristics of Nickel-Titanium files with three different filing motions such as vertical downward motion,reciprocating up and down motion and spiral up and down motion.Using Scanning Electron Microscope(SEM)observation analysis to compare the morphology of the fracture interface under three different filing motions.The results showed that when the spiral up and down motion was used during root canal preparation,compared with other motions,the nickel-titanium instruments had the longest fatigue life time and were more used in clinical operations.Established filing force prediction model in root canal preparation.Combined with the root canal geometry,the root canal preparation filing process was divided into the stage of filing root canal vertical part and the stage of filing root canal bending part.The method of combining functional principles and instrument geometry was used in the stage of filing root canal vertical part,and the bending strain energy method was used in the stage of filing root canal bending part.Established the filing force prediction model for the Nickel-Titanium instruments structure parameters and processing parameters in two stages,respectively.The parameter calibration in the filing force prediction model was completed through experiments,and the three-dimensional model dynamic Boolean operation method established the relationship between filing removal volume and filing feed depth.Finally,experiments were used to verify the effectiveness of the mechanical model proposed in this paper.