Tensile Bond Strength of a Soft Liner to an Acrylic Resin after Primer Application and Thermocycling

Abstract

Purpose:The aim of this study was to evaluate the effect of a surface treatment with Sofreliner primer on tensile bond strength of a resin-based soft liner (Coe-Soft) bonded to a polymethylmethacrylate (PMMA) resin before and after accelerated aging simulated by a thermocycling machine. Material and Methods: One hundred and twenty rectangular specimens of PMMA resin were fabricated with 10 × 10 mm² of cross-section and 40 mm of height. The resin-based soft liner was positioned between two PMMA resin specimens. The specimens were divided randomly into 6 groups (n = 10) according to the surface treatment and accelerated aging cycles (0, 500 and 1000). After accelerated aging, specimens were submitted to tensile bond strength test. The fractures were classified as adhesive, cohesive or both. Results: Most failures were classified as cohesive (p = 0.025) and there was an increase on the mean values of tensile bond strength for group with primer application regardless the cycles of accelerated aging, and also an increase along thermocycling periods. The scanning electronic microscopy was used to illustrate the types of failures and the effect of primer application on PMMA acrylic resin surface. Conclusion: The primer application associated with resin-based soft liners is clinically viable, once this treatment strategy provides a reliable adhesion.

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

“…Also, it is important to consider that the NTP + Primer Sofreliner group presented higher bond strength in the initial period since NTP treatments in HMDSO and argon-containing plasmas are capable of increasing the surface energy, and consequently, acquire greater wetting capacity, as do the monomer and Sofreliner primer. 19,23,27,34 This result is in agreement with Bolayir et al, 34 who reported that the isobutyl methacrylate monomer could be used in association with the primer by optimizing the surface wetting of the denture resin and its bond to Meliodent silicone reliner. Furthermore, these authors reported that the acceptable tensile bond strength value reported in the literature varies from a minimum of 0.44 MPa to approximately 2.11 MPa.…”

“…This could have occurred because the bond between the acrylic resin and silicone is principally based on the composition of the interfacial adhesive used . Sofreliner Primer is composed of a solvent and bonding agent that react with the materials used in the present study, promoting greater chemical adhesion and resistance to the traction forces than other surface treatments, increasing the wettability of the resin …”

“…15,29 Sofreliner Primer is composed of a solvent and bonding agent that react with the materials used in the present study, promoting greater chemical adhesion and resistance to the traction forces than other surface treatments, increasing the wettability of the resin. 14,27,38 Although several studies aimed to develop different methods to improve the adhesion between silicone reliner and acrylic resin using primers and adhesives, bonding failures still occur. 10,14,16 Recently, published literature has reported the use of NTP to improve materials' adhesion properties by means of alteration of the chemical properties, without altering the physical properties.…”

“…The experimental design is illustrated in Figure , and the materials used in the present study are detailed in Table . Initially, 160 rectangular specimens of white ocular prosthesis resin with dimensions of 40 mm × 10 mm × 1 mm were prepared in metallic matrixes . Excess resin was removed with a Maxi‐Cut bur (Vicking, Sao Paulo, Brazil), and surface finishing was performed with 400‐, 600‐, 800‐, 1000‐, and 1200‐grit metallographic sandpaper (Buehler, Lake Bluff, IL) in a semiautomatic universal polisher (Ecomet 300PRO; Buehler) …”

“…Initially, 160 rectangular specimens of white ocular prosthesis resin with dimensions of 40 mm × 10 mm × 1 mm were prepared in metallic matrixes. 26,27 Excess resin was removed with a Maxi-Cut bur (Vicking, Sao Paulo, Brazil), and surface finishing was performed with 400-, 600-, 800-, 1000-, and 1200-grit metallographic sandpaper (Buehler, Lake Bluff, IL) in a semiautomatic universal polisher (Ecomet 300PRO; Buehler). 28 The specimens were randomly assigned to groups, and the surface to be in contact with the relining material received the treatment according to the following groups (n = 40 specimens/group): Sofreliner Primer; NTP; Sofreliner Primer + NTP; NTP + Sofreliner Primer.…”