Accuracy Of Digital Impression Using Intraoral Scanner For Edentulous Patients:a Systematic Review And Meta-analysis

Objective:This study conducted a systematic evaluation and meta-analysis on the accuracy of the digital impression obtained by the intraoral scanner for edentulous patients by retrieving the relevant literature on the accuracy of the digital impression obtained by the intraoral scanner,so as to provide some reference for the clinical application of the intraoral scanner in edentulous patients.Methods:According to the research questions,the corresponding retrieval strategies were developed to collect the research on the accuracy of the digital impression of edentulous jaws obtained by the intraoral scanner before June 15,2022.The databases include PubMedcweb of science,EMBASE,Cochrane Central Register of controlled trials(central),China National Knowledge Infrastructure(CNKI),Wanfang database China biomedical medicine database(CBM)and China Science and technology journal database(VIP).In addition,the references finally included in the literature were retrievedThe researchers conducted literature screening,data collection,bias risk assessment,and then performed data analysis and heterogeneity test with Stata se17.0 software.The extracted outcome measures were standardized mean differences(SMD)and 95%confidence intervals.The corresponding effect model was selected according to the heterogeneity,and descriptive analysis was performed on the data that could not be merged.Results:A total of 720 articles was searched.At last,18 studies were included.Among the 18 articles,7 were studies on the accuracy of digital impression obtained by intraoral scanner directly,and 11 were studies on the accuracy of scanning edentulous jaw model by intraoral scanner.The risk of bias assessment showed that 3 studies were low,11 studies were medium,and 4 were high.There was no significant difference in the trueness of intraoral digital impression obtained by intraoral scanner between upper and lower edentulous jaws(SMD 1.62;95%CI:-0.23～3.47).Three literatures were included,the heterogeneity was high,and more studies are needed to confirm the results.There was no significant difference in the trueness of the digital impression between the upper and lower edentulous jaw models obtained by the oral scanner for those with oral scanning experience(SMD 0.05;95%CI:-0.37～0.47).Three literatures were included with low heterogeneity.There was no significant difference in the precision of digital impression between upper and lower edentulous jaw models obtained by intraoral scanner(SMD-0.16;95%CI:-0.70～0.39).Three literatures were included with moderate heterogeneity,which needs further study and verification.Resin marker had no significant difference in improving the trueness of digital impression of edentulous jaw model,and two literatures were included(SMD-0.37;95%CI:-1.01～0.27);the heterogeneity is low.There was no significant difference in improving the precision of digital impression of edentulous jaw model by resin marker,2 papers included with;high heterogeneity(SMD 0.28;95%CI:-2.02～2.57).One showed that resin marker improved the precision of upper edentulous jaw,and another found that it reduced the precision of lower edentulous jaw.Oral scanning experience had no significant difference in the trueness of digital impression of edentulous jaw model obtained by intraoral scanner,and two literatures were included(SMD 0.71;95%CI:-0.07～1.49);the heterogeneity is moderate.Oral scanning experience will reduce the precision of obtaining digital impression of edentulous jaw model by intraoral scanner,2 papers with mild heterogeneity(SMD-0.40;95%CI:-0.68～-0.12).Conclusion:After a systematic review and Meta-analysis of the existing evidence,it is concluded that:1.The direct digital impression of the edentulous jaw obtained by the intraoral scanner is not recommended to be directly used for the production of complete dentures,but can be considered for the production of individual trays or diagnostic dentures.2.There was no significant difference in the accuracy of the upper and lower edentulous jaw models scanned by the intraoral scanner by those with oral scanning experience.3.Placing resin markers on the edentulous jaw model has certain influence on the accuracy of the digital impression obtained.4.Oral scanning experience will affect the accuracy of obtaining digital impression of edentulous jaw model.