A Preliminary Study On The Accuracy Of Digital Models With Intraoral Scanning In Patients Of Chronic Periodontitis

Objective:In this study,the accuracy of the 3 Shape TRIOS intra-oral scan(IOS)digital model and the hard tissue part of the traditional plaster model(TPM)were evaluated for the Actual measurement(AM)in the patients with chronic periodontitis,and the 3D deviation of the hard tissues of IOS and TPM was compared.In addition,analysis the correlation between the gingival parts of the two models and the depth of periodontal pocket,the degree of gingivitis and the position of the dental arch,investigate the accuracy of IOS and TPM in gingival soft tissue in patients with chronic periodontitis,so as to provide guidance for clinical application.Method:1.A preliminary study on the accuracy of intraoral scanning digital model for evaluating the hard tissue area of dentition in patients with chronic periodontitis.28 patients with chronic periodontitis who had received periodontal basic treatment and periodontal examination were selected to obtain the traditional plaster model with silicone rubber,and the digital model was obtained by 3Shape TRIOS intra-oral scan.The electronic calipers were directly measured in the oral cavity of patients with chronic periodontitis.The height of clinical teeth,the width of clinical teeth and the width of dental arch were recorded.3Shape D810 scanned the gypsum model and converted it into STL format file,and the intra-oral scan digital model was also converted to STL format file.The reverse engineering software Geomagic Qualify 2012 was introduced to 3D measurement,and the above indexes of the two models were recorded.In addition,the clipping and three-dimensional fitting of the teeth were aligned in the software,and the 3D deviations(RMS)of two models were recorded.With actual measurement value as the gold standard,the single factor ANOVA variance analysis is used to determine the accuracy of the hard tissue part of the dentition measured by intra-oral scan digital model and traditional plaster model,and 3D deviation of the tooth surface of the two models was compared intuitively.2.A preliminary study of the accuracy of gingival soft tissue area in patients with chronic periodontitis by intra-oral scan digital model.Patient inclusion and model acquisition are the same as 1,the surface morphology 3D deviation(G-RMS),gingival surface morphology 3D deviation(P-RMS)and the 3D deviation in the gingival surface of the anterior,middle and posterior segment(G-RMS1,G-RMS2,G-RMS3)of the dental arch were recorded.Single sample T test and chi-square test were used to analyze the relationship between 3D deviation on the gingival surface,periodontal pocket depth,and the degree of gingivitis.The variance analysis designed in the random area group was used to analyze the difference between G-RMS1,G-RMS2 and G-RMS3.Further analysis was carried out by Tukey test,and the 3D deviation of the gingival surface of the two models was compared.Result:1.A preliminary study on the accuracy of intraoral scanning digital model for evaluating the hard tissue area of dentition in patients with chronic periodontitis.With the reference of AM data,the accuracy of 3Shape TRIOS intra-oral scan digital model and traditional plaster model in measuring the dentition of chronic periodontitis were within 0.1mm.The accuracy of posterior end width of dental arch measured by the 3 Shape TRIOS intra-oral scan digital model is slightly lower than that of the traditional plaster model(intra-oral scan digital model maxillary:0.25mm,traditional plaster model maxillary:0.15mm,intra-oral scan digital model mandible:0.26mm,traditional plaster model mandible:0.14mm).The 3D deviation of the maxillary average tooth surface of the two models was 0.167 + 0.046mm,and the 3D deviation of the mandibular average tooth surface was 0.139 + 0.063mm,both in the acceptable range of clinical practice.2.A preliminary study of the accuracy of gingival soft tissue area in patients with chronic periodontitis by intra-oral scan digital model.After comparing the difference of gingival soft tissue between 3 Shape TRIOS intra-oral scan digital model and traditional plaster model,the following conclusions were reached.?.The depth of periodontal pocket had no effect on P-RMS of IOS and TPM(P>0.05).?.Gingivitis had no effect on P-RMS of IOS and TPM(P>0.05).?.The average G-RMS of maxilla is 0.081 + 0.216mm,and the average G-RMS of mandible is 0.074 + 0.183mm.The obvious deviation occurred mainly in the posterior segment of the dental arch,the margin of the gingiva and the papilla of the gingiva.?.The G-RMS of posterior arch IOS and TPM is larger than that of anterior and middle dental arch(P<0.05),which was 0.283mm,within the acceptable range of clinical practice.Conclusion:When the model of patients with chronic periodontitis was acquired,the accuracy of the tooth column and the gingival portion of the intra-oral scan digital model was within the acceptable range,and the intra-oral scan digital model can avoid tissue displacement caused by tooth column compression.This study considers that the intra-oral scan digital model is better in obtaining the model of chronic periodontitis.