The Comparison Of Accuracy For Conventional With Digital Impression

Objective: Utilizing three-dimensional(3D)model analysis of the accuracy of five different dental scanners when scanning whole dentition,the effect of different ways and impression materials on impression accuracy.Material and methods: 1.The 3D model date was used as the control group by using the Metrotom 1500 computed tomography(CT)scanning the standard maxillary resin dentition model.This model was then scanned three times with five scanners(inEos X5,D810,Ceramill MAP400,Arctica Autoscan,Cerec?AC Omnicam).The data of five groups was superimposed with the data of control group by the Geomagic software.The three-dimensional distance(3DD),the rate of the volume change(RVC)and surface triangle list mesh number were measured and compared.2.The experimental group was divided into four groups,one group was intraoral scanning group,the other group were alginate group,silicone group,polyether group.Three of the impression materials were subdivide into two groups: the female mold group and the male mold group.The model was fabricated on the standard maxillary resin dentition model by intraoral scanner-Cerec?AC Omincan(scanning 5 times)and by alginate,silicone,polyether(making impression 10 times).Five of impressions poured the plaster to get the stone cast.The five stone casts and the five impressions were scanned by inEos X5 scanner to get the group data.The data of experimental group was superimposed with the data of control group by the Geomagic software.The 3DD and RVC were measured and compared.Results: 1.Among the 3DD of five scanners,inEos X5 was similar with D810,and Arctica Autoscan was also similar Creamill MAP400,difference was without statistically significant(P>0.05).The value of Cerec?AC Omnicam was maximum,next it was Arctica Autoscan and Creamill MAP400,inEos X5 and D810 was the minimum,differences among them were statistically significant(P<0.05).Among the RVC of different scanners,there was not significantly between Arctica Autoscan and Creamill MAP400.The value of Cerec?AC Omnicam was maximum,next was the Arctica Autoscan and Creamill MAP400,followed by the D810,the inEos X5 was the minimum,there were significantly among them(P<0.05).There was not linear correlation between triangle mesh number and the accuracy of scanner(P>0.05).2.Among the 3DD and RVC of the female mold of three materials group and intraoral scanning group,there were not significantly between silicone female mold group and polyether female mold group(P>0.05),the value of them were the smallest;the next was alginate female mold group;intraoral scanning group is the largest(P<0.05).Among the 3DD and RVC of the male mold group of three materials group and intraoral scanning group have the same trend.The 3DD of female mold group and the male mold group were compared respectively,there was not significantly between polyether female mold and polyether male mold group;between silicone female mold and addition silicone male mold group(P>0.05).But there was significantly between alginate female mold and alginate male mold group.The RVC of female mold group and the male mold group were compared respectively,there was not significantly between polyether female mold and polyether male mold group(P>0.05).But there was significantly between alginate female mold and alginate male mold group;between silicone female mold and addition silicone male mold group(P<0.05).Conclusion: There are some differences in the accuracy of different system scanners,when scanning the whole dentition,the accuracy of the extraoral scanner is better than the intraoral scanner.When making impression of full dentition,the accuracy of the three impression materials is higher than that of the intraoral scanning group.Direct scanning impression can reduce the cost,it is recommended that scanning alginate and polyether impression.