Comparison of the marginal and internal fit of PMMA interim crowns printed with different layer thicknesses in 3D-printing technique

Abstract

Objective: The aim of this in vitro study was to compare the effect of printing layer thickness on the marginal and internal fit of interim crowns. Material and methods: A maxillary first molar model was prepared for ceramic restoration. Thirty-six crowns were printed with three different layer thicknesses using a digital light processing-based three-dimensional printer (25, 50, and 100 µm [LT 25, LT 50, and LT 100]). The marginal and internal gaps of the crowns were measured with replica technique. An analysis of variance was conducted to determine if there were significant differences between the groups (ɑ =.05). Results: The marginal gap of LT 100 group was significantly higher than that LT 25 (p =.002) and LT 50 groups (p ≤.001). The LT 25 group has significantly larger axial gaps than LT 50 group (p =.013); however, there were no statistically significant differences between other groups. The LT 50 group showed the smallest axio-occlusal gap. The mean occlusal gap differed significantly by printing layer thickness (p ≤.001), with the largest gap occurring for LT 100. Conclusions: Provisional crowns printed with 50 µm layer thickness provided the best marginal and internal fit. Clinical significance: It is recommended that provisional crowns be printed with a 50 µm layer thickness to ensure optimal marginal and internal fit.