Influence of disinfectants on the strength of bond of selected soft lining materials to acrylic denture base

Introduction
Soft liners create a cushioning layer of the mucosal part of a denture, which makes the occlusal forces transmission less traumatic and improves the comfort of wearing a prosthetic restoration.
Aim
The aim of the study was to evaluate the influence of disinfectants on the bond strength of selected soft liners to acrylic removable denture bases.
Material and methods
The samples of Silagum-Comfort, Mollosil and Mucopren were kept in different disinfectants and in saline. The study consisted in determining the maximum tensile stress at the moment when the bond between the silicone elastomer and the acrylic material was broken or when the cohesion of the lining material was lost. The experiment was conducted after 1, 14 and 30 days.
Results
The bond strength of the lining material to acrylate was weakest for Mollosil; it was 0.99 MPa on the 30th day of the experiment, for the sample immersed in sodium hypochlorite. Moreover, the samples placed in this disinfectant were characterised by a gradual loss of the pink colour of the elastic material. The results obtained for Silagum-Comfort and Mucopren did not differ significantly and were 1.8 MPa and 1.4 MPa, respectively.
Conclusions
1. The agents used for every-day denture hygiene may lower the bond strength of the elastomer material to the acrylic denture base. The deterioration of the mechanical properties may be particularly accelerated by strongly ionised solutions.
2. The number of adhesive and cohesive disconnections in the samples was similar, regardless of the type of the disinfectant applied.