Comparison of the marginal and internal fit of metal three-unit fixed dental prosthesis cast from wax and resin patterns fabricated using milling and three-dimensional printing technologies

초록

Purpose: This study aimed to compare the marginal and internal fits of metal three-unit fixed dental prosthesis (FDP) cast from wax and resin patterns produced using milling and three-dimensional (3D) printing technologies. Methods: To fabricate three-unit FDPs, the maxillary right first premolar and molar were prepared on an experimental model (AG-3 ZPVK, Frasaco GmbH), which was then duplicated in metal. The metal model was replicated, and working casts were fabricated using a type IV dental stone. These stone models were scanned using a desktop scanner to fabricate virtual models, allowing for the digital design of the three-unit FDPs. Overall, 30 patterns were fabricated using milling and 3D printing technologies (n=15). Subsequently, all patterns were cast into metal FDPs following conventional laboratory procedures. The marginal and internal fits of the fabricated metal FDPs were evaluated by scanning their inner and outer surfaces in situ on the metal model, followed by digital analysis. Differences in the fit between the two groups of FDPs were analyzed using an independent samples t-test (α=0.05). Results: A significant difference in marginal fit was observed between FDPs fabricated using milling and 3D printing technologies (p<0.001). The milling group exhibited superiority to the 3D printing group in terms of marginal fit (p<0.05). Conclusion: For the fabrication of wax patterns, the milling technology showed superiority to the 3D printing technology in terms of marginal fit for metal three-unit FDPs.

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