Effect of post‐print cleaning protocol on mechanical, optical, and conversion characteristics of two 3D‐printed resin composites for definitive crowns

Abstract

Abstract Purpose To evaluate the influence of post‐print cleaning protocols on the biaxial flexural strength, degree of conversion, and translucency of two 3D‐printed definitive crown materials with differing filler content. Materials and methods Lower‐filled (Detax Crown; 24.4 wt% filler) and higher‐filled (Rodin Sculpture 2.0; 60.2 wt% filler) 3D‐printed crown materials were subjected to five cleaning conditions: isopropyl alcohol for 5 s (IPA‐5s) or 60 s (IPA‐60s), Rodin Universal Resin Cleaner, Harvest InovaPrint Wash, or Saremco Print Cleaning Concentrate. Biaxial flexural strength (ISO 4049:2019), degree of conversion, and translucency were measured, and surface morphology was assessed by scanning electron microscopy (SEM). Two‐way ANOVA with Bonferroni adjustment and Spearman correlations were applied ( α = 0.05). Results IPA‐5s produced the numerically highest flexural strength in both materials, significantly so only for Sculpture 2.0, whereas Harvest and Saremco produced the lowest, and Rodin intermediate. IPA‐60s reduced the strength for Sculpture 2.0 ( p < 0.001) but not for Detax Crown ( p = 0.539). Sculpture 2.0 showed significant translucency reductions with all conditions except IPA‐5s, whereas Detax Crown translucency remained stable. IPA‐5s also produced the highest degree of conversion for both materials, with an exploratory correlation between mean flexural strength and mean degree of conversion across protocols ( n = 5 group means per material), reaching significance only for Detax Crown ( r s = 0.900, p = 0.037). SEM showed well‐embedded filler in Detax Crown across conditions, whereas Sculpture 2.0 showed greater filler exposure variability. Conclusion All alternative cleaning protocols reduced flexural strength and degree of conversion in both materials, but the optical response was material‐specific. Translucency varied only slightly in the lower filled material, whereas the higher filled material showed marked translucency loss with every protocol other than a 5‐s IPA wash. Extending IPA exposure from 5 to 60 s reduced strength, degree of conversion, and translucency in the higher filled material but not the lower filled material. Strength loss was accompanied by reduced degree of conversion in the lower filled material and, in the higher filled material, additionally by opacification and greater filler exposure on SEM.

The authors' abstract, as published at the source. Journal of Prosthodontics, 2026 · DOI ↗