Comparative Evaluation of the Effect of Different Surface Treatments on Bond Strength between Commercially Available Soft Liners and Denture Base Resin – An In Vitro Study

Introduction:This study was undertaken to evaluate and compare the effect of different surface treatments on bond strength between commercially available soft liners and denture base resin.Materials and methodology: Suitable specimens were prepared using the metal die.A total of 80 pairs of polymethyl methacrylate (PMMA) cylinders were prepared.The 80 pairs of PMMA cylinders were divided into two groups of 40 each, namely group A and group B. Group A denoted GC Reline, and group B denoted Mollosil.Each group was divided into four subgroups of 10 each, namely I, II, III and IV.The four subgroups underwent four different types of surface treatments (control, methyl methacrylate, acetone and sandblasting).The cylinders of group A and group B were lined by GC Reline and Mollosil, respectively.All the specimens were subjected to a tensile bond test.Testing was carried out in a universal testing machine (UTM) at a crosshead speed of 5 mm/min.All the specimens were placed under tension until failure in the specimen occurred. Results:The tensile bond strength of subgroups II, III and IV of both the groups (group A: 0.4920; group B: 0.3670) was higher than their respective control subgroups.Overall, the tensile bond strength of group A (GC Reline) was higher than that of group B (Mollosil).The tensile bond strength of group A was maximum in subgroup II (0.49), and the tensile bond strength of group B was maximum in subgroup III (0.38).Conclusion: Acrylate-based soft liners have a higher bond strength than silicone-based materials.This is due to the similar chemical compositions of the denture base material and the soft liner.An increase in tensile bond strength has been observed due to surface treatment of PMMA denture base resin with sandblasting, monomer and acetone.The tensile bond strength of GC Reline was maximum when the acrylic resin was treated with monomer, and the tensile bond strength of Mollosil was maximum when the acrylic resin was treated with acetone.So, according to the study, acrylic resin bonded to GC Reline soft liner when treated by sandblasting provides the best tensile strength and is recommended for clinical use.