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

Marcelo Coelho Goiato,Emily Vivianne Freitas Da Silva,Aljomar José Vechiato Filho,Amália Moreno,Rodrigo Antonio De Medeiros,Daniela Micheline Dos Santos,Mário Alexandre Coelho Sinhoreti

doi:10.1590/1516-1439.024415

Marcelo Coelho Goiato, Emily Vivianne Freitas Da Silva + Show 5 more

Open Access

https://doi.org/10.1590/1516-1439.024415

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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.

Highlights

The resilient denture liners are indicated for the restoration of inflamed support tissues, severe bone resorptions and low resilience mucosa because of their damping effect and by providing increased prosthesis stability[1,2,3,4].These materials are classified as resin-based soft liner and silicone-based soft liner[3] and are composed by monomers and polymers associated with plasticizers[5,6] which provide softness to the relining material and comfort to the patient[7]
Increased tensile bond strength results were observed along the thermocycling periods for both groups, regardless surface treatment
It can be assumed that the distribution of types of failure depended on the primer application

Summary

Introduction

The resilient denture liners are indicated for the restoration of inflamed support tissues, severe bone resorptions and low resilience mucosa because of their damping effect and by providing increased prosthesis stability[1,2,3,4]. These materials are classified as resin-based soft liner and silicone-based soft liner[3] and are composed by monomers and polymers associated with plasticizers[5,6] which provide softness to the relining material and comfort to the patient[7]. The aging may change the relining materials properties, providing loss of plasticizers and resilience reduction, affecting the adhesion[11].

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