Comparative Evaluation of Tensile Bond Strength between Silicon Soft Liners and Processed Denture Base Resin Conditioned by Three Modes of Surface Treatment: An Invitro Study

Abstract

Soft denture liners act as a cushion for the denture bearing mucosa through even distribution of functional load, avoiding local stress concentrations and improving retention of dentures there by providing comfort to the patient. The objective of the present study was to compare and evaluate the tensile bond strengths of silicone-based soft lining materials (Ufi Gel P and GC Reline soft) with different surface pre treatments of heat cure PMMA denture base acrylic resin. Stainless steel dies measuring 40 mm in length; 10 mm in width and 10 mm in height (40 × 10 × 10) were machined to prepare standardized for the polymethyl methacrylate resin blocks. Stainless steel dies (spacer for resilient liner) measuring 3 mm thick; 10 mm long and 10 mm wide were prepared as spacers to ensure uniformity of the soft liner being tested. Two types of Addition silicone-based soft lining materials (room temperature polymerised soft lining materials (RTPSLM): Ufi Gel P and GC Reline soft) were selected. Ufi Gel P (VOCO, Germany), GC Reline soft (GC America) are resilient, chairside vinyl polysiloxane denture reliners of two different manufacturers. A total of 80 test samples were prepared of which 40 specimens were prepared for Group A (Ufi Gel P) and 40 specimens for Group B (GC Reline soft). In these groups, based on Pre-treatment of acrylic resin specimens each group was subdivided into four sub groups of 10 samples each. Sub-group I-without any surface treatment. Sub-group II-sand blasted Sub-group III-treated with Methyl Methacrylate monomer Sub-group IV-treated with chemical etchant Acetone. The results were statistically analysed by Kruscal Wallis test, Mann-Whitney U test, and Independent t test. The specimens treated with MMA monomer wetting showed superior and significant bond strength than those obtained by other surface treatments. The samples belonging to subgroups of GC Reline soft exhibit superior tensile bond strength than subgroups of Ufi Gel P. The modes of failure of all specimens were mostly adhesive in nature. Surface pre treatments by chemical means improved the bond strength between the silicone liners and denture base.

Improvement of the Adhesive Strength between Silicone-Based Soft Liner and Thermocycled Denture Base with Plasma Treatment

“…Silicone-based soft liners tested in the present study had a satisfactory bond strength to thermocycled denture base resin, which is significantly higher than the values observed in other studies [15,30]. Apart from the chemical oxidation reaction, oxygen plasma also has roughening effect on polymer surface.…”

“…In order to prepare the resin blocks for tensile test, a mold was made by investing 2 brass dies of 8×10 mm 2 cross-sectional area and 30 mm length, together with a spacer (3 mm thick), in hard but flexible silicone rubber (Addition silicone duplicating material) [15]. Molten wax was poured in the mold and allowed to cool, harden and subsequently to be invested in dental stone in a dental flask.…”

Can Nonthermal Plasma Improve the Adhesion between Acrylic Resin for Ocular Prostheses and Silicone‐Based Relining Material?

“…Resilient relining materials are associated with resin and act to absorb and redistribute forces on the prosthesis . In addition, they are used to improve the adaptation of the prosthesis with the objectives of preserving support structures, giving comfort to the patient, and alleviating conditions of local chronic pain …”

“…Silicone‐based reliners maintain their properties for a longer period of time compared to resin‐based materials, but they do not possess adequate chemical adhesion to acrylic resin, thus requiring additional resources to optimize the bond . Among the resources cited in the published literature, the use of adhesive primers before the application of the relining material is highlighted.…”

“…Among the resources cited in the published literature, the use of adhesive primers before the application of the relining material is highlighted. This application forms a thin film between the acrylic resin and silicone . However, the bond created between the adhesive primers and the acrylic resin is not sufficient to impede detachment .…”