Effect of Surface Treatment on the Flexural Strength of Denture Base Resin and Tensile Strength of Autopolymerizing Silicone Based Denture Liner Bonded to Denture Base Resin: An In Vitro Study

Abstract

Silicone based denture liners are superior to acrylic based denture liners but it has a problem of failure of adhesion with the denture base. To evaluate the effect on the tensile bond strength of silicone based liner and flexural strength of denture base resin when the latter is treated with different chemical etchants prior to the application of the resilient liner. Rectangular specimens of heat cured PMMA (65 × 10 × 3.3 mm(3)) for flexural strength and (10 × 10 × 40 mm(3)) for tensile strength were fabricated and divided into four subgroups each. One subgroup of each type acted as a control and the rest were subjected to surface treatment with acetone for 30 s, MMA monomer for 180 s, methylene chloride for 15 s, respectively. Silicone based denture liner was processed between 2 PMMA specimens (10 × 10 × 40 mm(3)) in the space provided by a spacer, thermocycled (5(-)55°C) for 500 cycles and then their tensile strength measurements and flexural strength measurements were done. 180 s of MMA monomer treatment was found to be most effective in improving the bonding between the liner and denture base resin as well as producing the lowest decrease in flexural strength of denture base resin. Chemical treatment of denture base resin improves the bond strength of denture liner but it also decreases the flexural strength of denture base. So careful selection of chemical etchant should be done so as to produce minimum decrease in flexural strength of denture base resin.

Soft denture liners and sodium perborate: sorption, solubility and color change

“…The resilient denture liners are divided into two groups based on their chemical composition: acrylic polymers and silicone polymers [3][4] . Both have short and longterm use and can be polymerized at room temperature or at high temperatures [5][6] .…”

The effect of poly(methyl methacrylate) surface treatments on the adhesion of silicone-based resilient denture liners

“…These results are in accordance with other studies and support the hypothesis that MMA and EA surface treatments could improve the adhesion of silicone-based resilient denture liners. 2,6,11,12 Although the C group achieved an acceptable tensile bond strength, higher than 0.44 MPa, 6,7 according to the literature, these values could rise to 68% after MMA and EA surface treatments, 2,6 Other studies observed an increase in bond strength when these solvents were used as a component of denture liner adhesives, 11,12 which found that the PMMA surface softening by these agents was effective. 11 In contrast with other studies 2,6,20 that found a 45% increase in tensile bond strength, in the present study, the AC protocol did not improve the tensile bond strength between PMMA resin and silicone-based denture liner.…”

“…The surface treatment protocols evaluated in this study were previously established in the literature to achieve higher tensile bond strength between PMMA and resilient relining materials. 2,6,11 MMA monomer and AC and EA solutions have been reported as chemical agents used in PMMA surface treatments, 2,6,19,20 as have solvents of primers and adhesives provided by manufacturers. 11,12 However, the effect of these surface treatments on the PMMA surface properties and the relationship with tensile bond strength has not been well established.…”

“…The surface softening and porous topography observed for the MMA and EA treatments may improve adhesive penetration and mechanical interlocking, which favors the chemical bonds with the relining material. 6,12,20,21 However, longer surface treatments may decrease the flexural strength of PMMA 2,6 The increase in bond strength may not be caused simply by the modification of PMMA surface properties because these protocols produced different changes in the PMMA surface roughness and surface free energy (Fig. 1, Table II).…”

Bond Strength of Resilient Lining Materials to Denture Base Resin: A Systematic Review and Meta‐Analysis

“…The results of the meta‐analysis indicated that for silicone‐based liners subjected to tensile test, chemical agents are more effective than the other surface treatments. While most of the reviewed literature reported that chemical agents were more effective than the other surface treatments, a few studies reported that it was ineffective or provided similar outcomes to other procedures . Gundogdu et al reported that chemical agents were more effective than sandblasting, laser, and control groups to increase tensile bond strength of silicone‐based resilient lining material to PMMA.…”