Do 3D-printed and milled tooth-supported complete monolithic zirconia crowns differ in accuracy and fit? A systematic review and meta-analysis of in vitro studies.

ABSTRACT

STATEMENT OF PROBLEM: Additive (3-dimensional printing) and subtractive (milling) methods are digital approaches to fabricating zirconia restorations. Comparisons of their resultant fabrication accuracy and restoration fit are lacking. PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate the accuracy and fit of monolithic zirconia crowns fabricated by 3-dimensional printing and milling. MATERIAL AND METHODS: The PubMed (Medline), Scopus, Embase, Web of Science, Cochrane Library, and Google Scholar databases were searched up to August 2023. Eligible records were included, and the standardized mean difference (SMD) analyzed 4 outcomes: marginal fit, intaglio fit, trueness, and precision. Publication bias was analyzed with Trim-and-fill, the Egger regression test, and Begg funnel plot. Methodological quality was rated using the QUIN tool. RESULTS: A total of 15 publications were found eligible out of the initial 6539 records. The 3-dimensional printing group demonstrated a lower marginal fit (SMD=1.46, 95% CI=[0.67, 2.26], P<.001; I2=83%, P<.001) and trueness (SMD=0.69, 95% CI=[0.20, 1.18], P=.006; I2=88%, P<.001) and a significantly higher precision (SMD=-2.19, 95% CI=[-2.90, -1.48], P<.001; I2=56%, P=.045). The intaglio fit did not differ significantly across the study groups (SMD=0.77, 95% CI=[-0.22, 1.77], P=.127; I2=87%, P<.001). CONCLUSIONS: Given the high degree of heterogeneity, it can be cautiously concluded that while 3-dimensional printing led to greater precision, the outcomes of the 2 accuracy and adaptation parameters most crucial to the longevity of the restorations-trueness and marginal fit-showed the superiority of the milling technique.