Evaluation Of Accuracy And Clinical Application Of Direct Digital Individual Tray In Maxillary Edentulous Jaw Based On The New Scanning Strategy

Objective:The aim of this study is to analyze and compare the accuracy of scanning the standard maxillary edentulous model with the new scanning strategy;To study the accuracy of direct digitization individual trays in maxillaryedentulous with the new scanning strategy in intraoral scanner;Based on the satisfaction of doctors,to evaluatethe individual pallets made by three methods.To provide a theoretical basis for the direct digital individual tray of maxillary edentulous jaw with intraoral scanner.Methods:1.Standard model of maxillary edentulous:To scan the standard plaster model with 3shape810 and Trios intraoral scanner respectively,marked as reference model group(RM)and control group(CM).The standard model was drawn and scanned with an intraoral scanner using a zigzag scanning strategy,which was recorded as the experimental group(EM).Save thedataof three groups in STL and import them into Geomagic Studio software for best fitting.After alignment,conduct 3D deviation analysis to analyze the precision and trueness of the scanning with intraoral scanner after adopting the new scanning strategy.2.Trueness of direct digitization individual trays formaxillary edentulous:selectesix patients withmaxillaryedentulous to make conventional alginate primary impression and red paste primary impression for each patient,which were recorded as conventional impression group(CP)and indirect digital impression module(IP);Intraoral scanner(Trios)combined with the new scanning strategy was used to obtainthe initial impression in the patient’s mouth,which was recorded as direct digital impression set(DP).Routinely make individual pallets of CP Group and obtain the final impression.Use 3 shape software to CAD individual trays of IP group and DP group,and use ultracraft A2D intelligent printing equipment to 3D print Ultraprint high-precision model resin individual trays,and then obtain the final impression.The STL data of the initial impression and final impression obtained by the three methods are imported into Geomagic Studio software for best fitting.After alignment,three-dimensional deviation analysis is carried out to analyze the trueness of direct scanning in the mouth by the intraoral scanner after adopting the new scanning strategy.3.On the premise of physician satisfaction,make a preliminary evaluation of the individual palletsthefor three methods with VAS scale,and compare and analyze the clinical application differences of the individual pallets.4.The data were processed by SPSS26 statistical software.The data were expressed as mean±standard deviation.Use paired t-test,and P<0.05 was statistically significant.Results:1 Scanning the standard model of maxillaryedentulous:the precision of CM group(31.24±12.76μm),EM group(30.70± 6.97μm),and there was no statisticaldifference between the experimental group and the control group(P>0.05);The trueness of CM group(214.50±59.84μm)and EM group(180.64 ± 51.55μm),P<0.05,the difference was statistically significant.2.Patients with maxillaryedentulous:the truenessof primary impression in IP group(393.90 ± 63,70μm)and DP group(158.67±17.39μm),the difference between the two groups was statistically significant(P<0.05),DP group with new scanning strategy had better accuracy than IP group.The trueness of the final impression was compared with that of CP Group.There was no statistically difference between IP group(250.80± 28.30μm)and DP group(214.10± 13.00μm)(P>0.05).3.The overall satisfaction of trays:DP(7.50±0.32)>IP(7.45±0.31)>CP(7.40± 0.32),the difference between the three groups was statistically significant;The satisfaction of tray edge,DP(7.50± 0.80)>IP(7.20± 0.65),the difference between them was statistically significant;The plastic satisfaction:DP(7.68± 0.43)>IP(7.61± 0.39)>CP(7.48± 0,41),There was no significant difference between IP and DP groups,but there was significant difference between IP and CP,DP and CP.There was no significant difference in the satisfaction of the overall shape,stability and final impression quality among the three groups.Conclusion:1 The new scanning strategy of line drawing combined with zigzag scanning path can improve the accuracy of intraoral scanner when scanning maxillary edentulous model,but has no effect on the precision.The new scanning strategy can effectively improve the accuracy of extraoral model scanning.2.The new scanning strategy of using the mixture of pressure indicating paste and zinc oxide eugenol to draw lines in the mouth and combined with zigzag scanning path can improve the accuracy of maxillary edentulous primary impression by direct digtal scanning.The three-dimensional deviation analysis between the final impression of indirect digitization and direct digitization the final impressioncompared with conventional individual tray is not statistically significant,and there is no significant difference in the quality of the final impression prepared by the two methods.It is feasible to use the new scanning strategy to directly digitize the maxillary edentulous primary impression for making individual trays,and there is no significant difference between the quality of the final impression by different individual trays.3.In the VAS scoring table,it was found that the direct digital individual tray with the new scanning strategy had better satisfaction in overall satisfaction,tray edge satisfaction and edge plastic satisfaction,which was higher than the indirect digital individual tray.The direct digitization of individual trays using the new scanning strategy has high satisfaction of doctors and meets the requirements of clinical use,which can be considered to be popularized in clinic.