BACKGROUND: Dental crowns have surface pollutants after their manufacturing. We know that these pollutants can be a source of peri-implant inflammation for some cases. This study aimed to compare two dental crowns cleaning methods that are simple and quick to apply in the dental lab. OBJECTIVES: To characterize qualitatively and quantitatively the pollution of transmucosal parts of zirconia monolithic crowns after supra-mucosal glazing in the lab and to compare the efficacy of steam versus ultrasonic cleaning protocols. MATERIAL AND METHODS: Eighteen customized zirconia monolithic crowns were divided into two groups of 9 crowns receiving a different cleaning protocol. The first group was treated with steam cleaning, whereas the second group was initially rubbed with a sterile compress soaked in a detergent and then cleaned in three successive ultrasonic baths containing a detergent, sterile water, and 70% ethanol. The presence and nature of the contaminants were investigated by BSE-SEM and energy-dispersive X-ray spectroscopy microanalysis. RESULTS: Organic (e.g., paint, sweat) and inorganic (e.g., zirconia fragments, silica, and metals) were identified on the surface of the zirconia crown before the cleaning treatments. At baseline, pollutants cover 0.51% ± 0.26% of the total area. This percentage dropped, respectively, to 0.02% ± 0.03% after steam cleaning (p <
0.0001) and to 0.02% ± 0.01 after the ultrasonic cleaning protocol (p = 0.0026). No difference was observed between the two decontamination techniques (p >
0.9999), but the variance in the steam group was higher compared to the ultrasound group (p = 0.0042). CONCLUSIONS: Both protocols allowed the cleaning of the transmucosal parts of the zirconia crowns to an extent of 99.98% of the studied surface. However, the ultrasound technique displayed less variability in the removal of residual pollutants and therefore should be preferred.