Eur J Orthod. 2023 Nov 18:cjad069. doi: 10.1093/ejo/cjad069. Online ahead of print.
BACKGROUND: The widespread use of CAD/CAM transfer trays warrants evaluation of their accuracy as compared to PVS transfer trays.
OBJECTIVES: To quantify the accuracy of CAD/CAM and PVS transfer trays, investigating any differences between soft and hard trays CAD/CAM transfer trays.
SEARCH METHODS: Eight different databases (Scopus, Web of Science, PubMed, Google Scholar, ProQuest, Embase, Cochrane Library, ClinicalTrials.gov) were searched, without restrictions, up to an end date of February 2023.
SELECTION CRITERIA: Clinical trials (randomized and non-randomized) and in vitro studies reporting average imprecision values for bracket positioning obtained by digital superimpositions of digitally planned and real positions.
DATA COLLECTION AND ANALYSIS: Data eligibility, data extraction, and risk of bias (RoB-2 and ROBINS-I) were conducted independently. The data, where possible, were synthesized and quantitatively analysed (meta-analysis of mean differences with 95% confidence intervals). The Grade of Recommendation, Assessment, Development and Evaluation (GRADE) analysis of the quality of evidence was performed. The t-test for independent samples was used to compare the transfer accuracy of hard and soft CAD/CAM transfer trays.
RESULTS: Thirteen studies were synthesized in this systematic review, and then eight studies were included in the quantitative meta-analysis. As regards linear measurements, there was a mean transfer error of 0.0752 mm (95%CI: 0.0428, 0.1076) for mesiodistal measures, 0.0943 mm (95%CI: 0.0402, 0.1484) for vertical, and 0.0815 mm (95%CI: 0.0469, 0.1160) for buccolingual. As for angular measurements, there was an average transfer error of 1.2279° (95% CI: 0.6011, 1.8548) for inclination, 0.9397° (95%CI: 0.4672, 1.4123) for angulation, and 0.8721° (95%CI: 0.4257, 1.3185) for rotation. CAD/CAM transfer trays were less accurate than polyvinylsiloxane (PVS) transfer trays, with those made of soft material being more accurate than the hard ones, except for vertical dimension. The GRADE quality of evidence ranged from very low to moderate.
CONCLUSIONS AND IMPLICATIONS: CAD/CAM transfer trays provide high bracket positioning accuracy, with soft transfer trays offering greater precision than rigid ones. Future randomized prospective trials are required to enhance the strength of the available evidence.
REGISTRATION: Prospero (CRD42023401278 number).