Marta Revilla‐León

Purpose To compare the effect of different pre‐cementation surface treatments and bonding protocols on the retention force of additively manufactured (AM) implant‐supported interim crowns. Material and methods A total of 50 AM interim crowns (Temporary CB resin) were cemented on implant abutments. Five groups ( n = 10) were established based on the different surface pre‐treatments performed in the intaglio surface of the specimens: no surface pre‐treatment (Group C or control), air‐abraded with 50‐μm aluminium oxide particles (Group AP) , air‐abraded with 50‐μm aluminium oxide particles followed by the application of silane (Group AMP), silane (Group MP), and air‐abraded with 30 μm silica‐coated aluminum oxide particles followed by the application of silane (Group CMP). Each specimen was cemented into an implant abutment using a composite resin cement (Rely X Unicem2). Afterward, the specimens underwent retention testing with a Universal Instron machine. Pull‐off forces (N) and modes of failure were registered. Statistical analysis was performed using Mann‐Whitney U tests with Bonferroni corrections for multiple tests (α = 0.05). Results The median retention force values were 233.27 ±79.28 N for Group Control, 398.59 ±68.59 N for Group MP, 303.21 ±116.80 N for Group AMP, 349.31 ±167.73 N for Group CMP, and 219.85 ± 55.88 N for Group AP. The pull‐off forces were significantly greater for Group MP, while the differences between the remaining groups were not statistically significant ( P > 0.05). Group AP showed the lowest retention force values among all the groups. Failure modes after the pull‐off testing were predominantly adhesive and substrate failure of the AM interim material. Conclusions The surface treatment of the intaglio AM crown tested significantly influenced the retention force values measured. Pre‐treatment with an MDP‐containing silane improved the retentive force values computed, whereas pre‐treatment with 50‐μm Al 2 O 3 air‐particle abrasion alone is not recommended prior to cementation on a titanium‐based implant abutment.