Surface modification of chromatography adsorbents by low temperature low pressure plasma

Effect of argon plasma and Er:YAG laser on tensile bond strength between denture liner and acrylic resin

STATEMENT OF PROBLEM

The separation of a denture liner from the denture base can be a clinical problem. Different surface treatments to increase the bond have been evaluated, but studies comparing the effect of argon plasma and erbium-doped yttrium aluminum garnet (Er:YAG) laser on the bond between acrylic resin and a denture liner are lacking.

PURPOSE

The purpose of this in vitro study was to evaluate the effect of argon plasma and Er:YAG laser treatments on the bond strengths of acrylic resin to 2 denture liners.

MATERIALS AND METHODS

Heat-polymerized acrylic resin (Acron Duo) was bonded to silicone soft-liner materials (Molloplast B, n=30; Mollosil, n=30) to create control specimens (n=10), argon plasma treatment (n=10), and Er:YAG laser treatment (n=10). Silicone liners were polymerized on resin specimens. The tensile bond strength test was performed with a crosshead speed of 10 mm/min with a 10-N load until failure. Data were analyzed by using the Kruskal-Wallis test and unpaired t test (α=.05).

RESULTS

The laser group showed significantly higher bond strength than the argon plasma group for both Molloplast-B (P=.001) and Mollosil (P<.001). The highest tensile bond strength values were determined in the laser-treated Molloplast-B group (1.325 ±0.119 MPa) while the lowest bond strength values were determined in the Mollosil control group (0.384 ±0.018 MPa).

CONCLUSIONS

Argon plasma and Er:YAG laser applications increases the tensile bond strength between soft-liner material and resin. Er:YAG laser treatment results in higher bond strength values than treatment with argon plasma for 1 minute.

Mathematical modelling of expanded bed adsorption - a perspective on in silico process design

Expanded bed adsorption (EBA) emerged in the early 1990s in an attempt to integrate the clarification, capture and initial product concentration/purification process. Several mathematical models have been put forward to describe its operation. However, none of the models developed specifically for EBA allows simultaneous prediction of bed hydrodynamics, mass transfer/adsorption and (unwanted) interactions and fouling. This currently limits the development and early optimization of EBA-based separation processes. In multiphase reactor engineering, the use of multiphase computational fluid dynamics has been shown to improve fundamental understanding of fluidized beds. To advance EBA technology, a combination of particle, equipment and process scale models should be used. By employing a cascade of multiscale simulations, the various challenges EBA currently faces can be addressed. This allows for optimal design and selection of equipment, materials and process conditions, and reduces risks and development times of downstream processes involving EBA. © 2018 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.