Accuracy of 3D Printing in Orthodontics: A Systematic Review and Meta-analysis

Abstract

To assess and compare the accuracy of 3D-printed digital models, orthognathic surgical splints, retainers or aligners, and implant surgical guides printed using various 3D printing technologies. The search comprised prospective and retrospective studies related to the accuracy of 3D-printed models, splints, implant surgical guides, and retainers/aligners in patients undergoing orthodontic and orthognathic surgical procedures. The outcomes were assessed in terms of linear measurements, degree of fit, and positional deviations in comparison to conventional plaster models and surgical acrylic splints. The methodologic quality of the articles and the level of evidence were assessed using the QUADAS-2 tool. A meta-analysis was performed to compare the accuracy of models printed by different technologies to plaster models using the random-effects model. Twenty-one retrospective studies were included. Quality assessment of all included articles showed moderate risk of bias and no article was excluded. The systematic review showed that there were no significant differences between printed surgical splints, retainers/aligners compared, and the control group. Meta-analysis of six eligible studies showed that printed models had a general trend toward overestimation of linear measurements (mean difference = 0.22 mm; 95% confidence interval = – 0.09 to 0.36 mm, I 2 = 85%). Measurements made on digital light processing-printed models were significantly different than those made on plaster models. The mean difference of 0.22 mm in linear measurements made on 3D-printed models and plaster models was clinically acceptable. Among the various printing technologies, PolyJet and fused deposition modeling-printed models showed higher accuracy. The printed splints and retainers/aligners were as accurate and reliable as their respective gold standards. The findings should be interpreted with caution due to high level of heterogeneity. PROSPERO Registration Number: CRD42020175511