Comparative evaluation of marginal fit of three-dimensional-printed provisional crowns with two different build angles and layer heights using triple scan protocol: An in vitro study

This in vitro study evaluated how build angle and layer thickness affect the marginal fit of provisional crowns fabricated by digital light processing (DLP) 3D printing, an important consideration for restoration success. This was an in-vitro study. Twenty-four provisional crowns were 3D-printed using a DLP printer and divided into four groups (n = 6 each) based on build angle (150° vs. 180°) and layer height (20 µm vs. 40 µm): Group I - 150°, 20 µm, Group II - 180°, 20 µm, Group III - 150°, 40 µm, and Group IV - 180°, 40 µm. Using a triple-scan protocol, researchers scanned the master die, the internal surface of each crown, and the seated crown. The Kruskal-Wallis test and Bonferroni post hoc analysis were used. All groups demonstrated clinically acceptable marginal fit, but the differences were statistically significant (P < 0.05). The best fit was achieved in Group IV (180° build angle and 40 µm layer height) with a marginal gap of 0.05 ± 0.02 µm. The least accurate was Group II (180°, 20 µm), showing a gap of 0.27 ± 0.25 µm. From the study, it was determined that 3D-printed provisional crowns with higher build angles and larger layer heights, i.e. Group IV: build angle 180° and layer height 40 µm, exhibited improved marginal fit.