Flexural strength of milled occlusal splints in pmma vs. 3d printed occlusal splints.

Abstract

Introduction: Occlusal splints are essential in the management of bruxism and temporomandibular disorders. Flexural strength is a critical mechanical property that determines their durability and clinical performance. With the expansion of digital dentistry, it is necessary to compare the behavior of splints manufactured by CAD/CAM milling of PMMA versus those obtained by 3D printing, given the variability reported in their mechanical properties. Objective: To determine, through a systematic review, the flexural strength of occlusal splints milled in PMMA compared to those produced by 3D printing. Methodology: A systematic search was conducted in PubMed, Scopus, Web of Science, and Cochrane databases (2019–2025), following PRISMA guidelines. Studies comparing both fabrication techniques were included. A total of 11 articles were analyzed: 8 in vitro studies, 2 systematic reviews, and 1 meta-analysis. Results: Milled PMMA splints showed an average flexural strength of 100–115 MPa, compared to 70–95 MPa for 3D-printed splints, indicating a 25–30% difference. PMMA exhibited lower water absorption (1–1.5% vs. 3–5%) and greater stability after aging. Some dimethacrylate-based resins reached values of 90–95 MPa, narrowing the mechanical gap. Conclusions: Milled PMMA remains the reference standard due to its superior strength and durability. However, 3D printing represents a viable alternative for cases with lower functional demands, particularly when using high-performance resins and optimized post-curing protocols.