A Comparative Evaluation of Shear Bond Strength Between Different Soft Liners to Heat-Cured Acrylic Resin Versus 3D Printed Denture Bases (An In-Vitro Study)

Introduction: It is crucial to study the interaction between chairside softliners and the most recent denture base materials, as it is vital in ensuring optimal results. Objective: To compare the shear bond strength of two chairside softliners using traditional heat-cured acrylic resin and innovative 3D-printed denture base resin material. Materials and Methods: 80 specimens with 50 x 10 x 3 mm dimensions were produced. The specimens were classified into two groups (n = 40) based on the type of denture base material used: heat-cured acrylic resin and 3D-printed resin. Each group was divided into two subgroups (n = 20), resulting in ten pairs (n = 10) per subgroup. The subgroups were distinguished based on the type of soft-liner material bonded to the denture base: subgroup A used a silicon-based soft liner, while subgroup B used an acrylic-based soft liner. Results: According to the study, the group that used heat-cured PMMA (Group I) had a significantly higher shear bond strength of (0.632 MPa) compared to the 3D printed group (Group II) with a shear bond strength of (0.397 MPa). Moreover, the silicon-based soft-liner subgroups had a slightly higher shear bond strength (0.566 MPa) than the acrylic-based soft-liner subgroups (0.463 MPa). However, this difference was not statistically significant.Conclusion: Heat-cured acrylic resin material showed higher shear bond strength than 3D-printed resin material. The silicone-based soft liners had better shear bond strength than the acrylic-based soft liners.