OBJECTIVES: To report up to 9-year results of a prospective and retrospective study on non-invasive full-mouth rehabilitation of worn dentition with PICN CAD-CAM restorations using the One-Step No-Prep technique. The secondary objective is to evaluate the influence of restoration thickness on fracture of restorations. METHODS: A total of 580 Vita Enamic restorations (218 anterior and 362 posterior
260 monoblock (MO) and 320 multiColor (MC)) in 24 patients were clinically evaluated once a year (up 9 months to 9 years) according to FDI criteria. Patient data and prosthetic parameters were registered. The minimum thickness of restorations was measured in 15 patients. RESULTS: The Kaplan-Meier survival rate of restorations at 9 years was 98.4 % (100 % for anterior and 96.7 % for posterior) and the success rate was 79.7 %, while the success rate excluding minor chipping requiring only polishing as failure was 86.7 %. Actually, minor chipping was the leading cause of failure and significantly more fractures were observed in the posterior region (9.2 times higher risk), particularly in the first and second molars or when the restoration thickness was less than 0.56 mm. Except for fracture, FDI evaluation showed clinically acceptable results for all restorations, mostly rated as excellent. Results remained consistent over time, including material luster and color, with no staining. MC showed superior esthetics compared to MO. Patient satisfaction was high. SIGNIFICANCE: The One-Step No-Prep technique exhibits successful long-term outcomes, and PICN (hybrid ceramic) is an appropriate material for this non-invasive treatment of tooth wear. Nevertheless, the minimum thickness of posterior restorations should be 0.6 mm, particularly at occlusal contact points. MultiColor blocks are recommended for esthetics.