An In Vitro Study Of 3D Printing Technology In Positioning The Calcified Root Canal Orifice Of The Maxillary First Molar

Objective:By simulating the calcified root canal of the maxillary first molar in vitro,the 3D printing technology can evaluate the positioning of the root canal guide and the accuracy of unclogging the calcified root canal,providing a preliminary experimental basis for the application of the 3D printing guide to the treatment of the calcified root canal of the molars.Methods:1.According to the inclusion and exclusion criteria,a total of 24 maxillary first molars were included(MB2 was excluded,and the total number of root canals was 72).2.The experiment uses the same software to obtain CBCT imaging data.According to the experimental process,it is divided into preoperative control group(group A),simulated calcified root canal imaging group(group B),and simulated calcified root canal design virtual path group(group C)),guided postoperative imaging group(group D).First of all,CBCT(group A)was taken before all root canals,and the root canal was pre-filled to simulate calcified root canals.CBCT was taken again(group B)to analyze whether the established simulated calcified root canal model was successful.After confirming that the modeling is successful,all simulated calcified root canals are designed and produced with 3D guide plates using Eguide implant software to locate the calcified root canal orifice of the maxillary first molar(Group C),and the root canal orifice is removed with the ET20 ultrasonic tip according to the orientation of the guide plate.Calcification to 2mm below the root canal orifice(group D).Mimics21.0 software was used to measure the difference between the maximum meso-distal median diameter and buccal tongue diameter of the root canals of groups A and B at the root canal orifice and 2mm below the root canal orifice.The 3-matic13.0 software measured the mesiodistal,buccal-lingual,crown-root deviation and angular deviation of the root canal orifice and 2mm below the root canal orifice of each canal in groups B,C,and D.3.Using SPSS 22.0 software for statistical analysis,the deviation of the mesiodistal diameter and the buccal tongue diameter in groups A and B was analyzed by inspection.Groups B,C and D used single-factor repeated measures analysis of variance to compare the size and difference of deviations between the three groups.In order to evaluate the reliability of the measurement,the same operator performed three measurements on the experimental data in different time periods.Results:1.The results of this experiment show that the preoperative control group(group A)and the simulated calcified root canal imaging group(group B)have the difference between the proximal and distal diameters and the buccal and tongue diameters of the root canal orifice and 2mm below the root canal orifice.There was no significant difference(P >0.05),suggesting that the method of filling the simulated calcified root canal with root canal inverted preparation is successful.2.The results of locating the calcified root canal orifice of the maxillary first molar by D printing technology show: the average linear deviation of the simulated calcified root canal image group(group B)and the virtual path group after the simulated calcification root canal(group C)in the root canal orifice It is 0.14-0.16 mm,the average linear deviation of 2mm under the root canal orifice is 0.16-0.22 mm,and the angular deviation is 1.61°.The average linear deviation between the simulated calcified root canal imaging group(group B)and the guided postoperative group(group D)at the root canal orifice is 0.14-0.17 mm,and the average linear deviation for 2mm under the root canal orifice is 0.16-0.22 mm.The angular deviation is 1.63°.After simulating calcified root canals,the average linear deviation between the virtual path group(C group)and the guided postoperative imaging group(D group)in the root canal orifice is 0.14-0.15 mm,and the average linear deviation in the 2mm below the root canal orifice is 0.16-0.22 mm,the average deviation of the angle is 1.63°.Comparing the precision measurement of the deviations between the three groups,the results showed that there was no statistical difference in the three-dimensional(mediodistal,buccal-lingual,and crown-root)deviations between the groups(P >0.05),and there was no statistical difference in the angular deviation(P = 0.089).It is suggested that the method of positioning and dredging the calcified root canal using 3D printing guide plate is feasible and highly accurate.Conclusion:1.The method of simulating root canal calcification in this experiment is feasible and can be used in subsequent experiments.2.The method of using 3D printing guide to assist in positioning and dredging the calcified root canal orifice has high accuracy,and provides a more minimally invasive and rapid method for the positioning and dredging of the calcified root canal orifice of posterior teeth,thereby reducing clinical ease Complications such as root canal perforation,step formation,broken instruments,and excessive removal of dental tissue,improve the success rate of root canal treatment,and provide a preliminary experimental basis for the use of 3D printed guide plates to guide the clearing of calcified root canals of molars.