Data extraction
CAD, Tooth
CAD
Two authors (JQ and DW) conducted the data extraction as well as risk of bias assessments independently, and any disagreements were resolved through consensus. The following information was extracted: 1) Author and year of publication; 2) Study design; 3) Groups; 4) Tooth die or model type; 5) Sample type; 6) Method used for evaluating the fit accuracy of the rest); 7) Sample size; 8) Main outcomes; 9) Scanning information; 10) CAD software; 11) Manufacturing machine; 12) Finishing and polishing. We contacted the corresponding authors of individual studies for missing data or additional study information. And those with no respondence after three contact attempts were excluded from meta-analysis and included in the qualitative aspect of this review. For studies that reported the gap distance values before and after polishing of the samples, the data after polishing was selected for the global meta-analysis. And for studies that evaluated vertical and horizontal distances between the RPD rests and rest seats, only the horizontal data (distances between the bottom of rests and rest seats on the occlusal surface of the tooth) was extracted.