Impact of material and silicone index support using additively manufactured trays on the reproducibility of diagnostic trial restorations (mock-up): A comparative in-vitro study.

Objectives: To investigate the impact of material selection and silicone index support, provided by an additively manufactured tray, on the trueness of diagnostic trial restorations (mock-ups), fabricated using bis-acrylic resin loaded into silicone indexes.

Methods: A scan of a fully dentate patient was obtained, and diagnostic virtual waxing was performed to create two different designs: one representing a purely additive and the other featuring a combination of additive and non-additive approach. For each design, 60 silicone indexes were fabricated and divided into six groups. Four groups were based on 4 different additional silicone impression materials. Two additional groups were fabricated using silicone indexes supported by additively manufactured trays. The fabricated indexes were loaded with a self-cure bis-acrylic composite and fitted onto 3D-printed models. The linear discrepancy and 3D quantitative deviation between each diagnostic trial restoration and the digital waxing were calculated using metrology software.

Results: The type of addition silicone used for fabricating the indexes, as well as their support by an additively manufactured try had a significant effect on the trueness of the fabricated diagnostic trial restorations (p < 0.05). The thickness of the fabricated diagnostic trial restorations was influenced by the thickness of the diagnostic waxing, the tooth type and section (p < 0.05).

Conclusions: Diagnostic trial restorations fabricated through molding presented an increased thickness compared to the corresponding virtual diagnostic waxing, regardless of the silicone index material or support. The use of an additively manufactured tray to support the silicone index can be beneficial, reducing the discrepancy between the produced diagnostic trial restorations and virtual diagnostic waxing.

Clinical Significance: The use of an additively manufactured tray in conjunction with the silicone index can standardize the fabrication of the silicone index and increase the accuracy of diagnostic trial restorations fabricated though the molding technique, potentially resulting in a more precise treatment plan, avoiding the drawbacks associated with extremely hard silicone indices.