Efficacy of 3D-Printing Additive Manufacturing in Comparison to CAD-CAM, and Conventional Method for Fabrication of Interim Crowns: A Systematic Review and Meta-Analysis

Objective: The present systematic review and meta-analysis aimed to determine the marginal and internal fit of the interim crowns fabricated utilizing the 3DP technique as compared with milling and molding methods. Methods: An electronic search was conducted in PubMed (MEDLINE), Scopus, and Web of Science on 14th October 2023 without any restriction on language and year of publication to answer the following focused question based on the PICO format: "Do interim crowns (P) fabricated using 3DP approaches (I) have better marginal and/or internal fit (O) as compared to conventionally fabricated (molding) and CAD-CAM (milled) interim crowns (O)?". The study employed the inverse variance statistical method using a fixed-effect model with standard mean difference (SMD) due to varied recording scales. Results were expressed with a 95% confidence interval (CI), and heterogeneity was measured using chi-square and I2. Statistical significance was set at p < 0.05. Result: The meta-analysis revealed the presence of statistically significant differences in the marginal fit between interim crowns fabricated using 3DP and milling techniques (SMD: -0.48; 95% CI: -0.70 to -0.27; p < 0.0001) as well as molding techniques (SMD: -0.80; 95% CI: -1.10 to -0.49; p < 0.00001). Similarly, the presence of statistically significant differences in the internal fit was observed using 3DP and milling techniques (SMD: -0.63; 95% CI: -0.87 to -0.39; p < 0.00001). All included studies were graded as 'medium' quality. Conclusion: Significant differences were revealed between the marginal and internal fit of interim crowns fabricated using the 3DP approach as compared with the milling and molding techniques. Hence, the 3DP approach can be used as an alternative to the CAD-CAM milled and conventionally fabricated interim crowns. However, clinical trials with diverse cases are required, considering cost, esthetics, and mechanics for broader applications.