Purpose: The purpose of this in vitro study was to evaluate the wear of different occlusal splints and opposing fixed restorations. Methods: Three different occlusal splints with two different antagonists were used (n=10). A full dentate typodont was used with an occlusal splinton the upper arch opposing crowns on lower posterior molars either porcelain fused to metal (PFM) or veneered polyetheretherketone (PEEK). Group I: 3D printed occlusal splint Group II: Heat-cured occlusal splint Group III:vacuum-formed occlusal splint. All specimens were tested by chewing simulator including the application of (50N) load for 75,000 cycles to simulate 6 months. Surface roughness and volume loss of all specimens were measured using an optical profilometry before and after the chewing simulation.Descriptive statistics, Student t-test and one-way ANOVA were done.Pearson’s correlation was done between volume loss and roughness change. Results: 3D printed group recorded the lowest surface roughness change and volume loss (p≤0.0001, p=0.0013<0.05). Total volume loss against PFM was statistically significantly higher than the volume loss against PEEK (p=0.014< 0.05). Pearson linear showed that there was a weak positive relation between surface roughness and volume loss. Conclusion: 3D printed occlusal splints are more wear-resistant after wear simulation for 6 months. The effect of the antagonist on the wear of the splint could be considered as PFM causing more wear on the splint than the PEEK. Clinical significance:Using 3D-printing technology in production of occlusal splints can improve wear resistance of the occlusal splints made for bruxers especially those with PFM restorations.