Comparative study of water sorption, solubility, and tensile bond strength of two soft lining materials

Abstract

Statement of problem: Two soft denture lining materials with distinct chemical compositions were evaluated to determine whether these compositional variations manifest themselves in property differences.

Purpose: This study evaluated and compared the water sorption, solubility, and tensile bond strength of a recently introduced silicone-based soft liner (Luci-sof) and a plasticized acrylic resin soft liner (Permasoft) using 2 processing techniques, laboratory-processed and autopolymerized at chairside, for the latter.

Material and methods: For water sorption and solubility testing, 24 disks (45 mm in diameter and 1 mm in thickness) were prepared for each group, stored in distilled water at 37 degrees C, and tested after 1, 4, and 6 weeks. The disks used for the first week were again tested after 4 and 6 weeks of continuous storage. Their weight was recorded and sorption and solubility were calculated using 2 methods. Two PMMA cylinders (25 mm in diameter, 25 mm in length), joined together by the soft liner, were used to determine the bond strength in tension at a loading rate of 2 mm/min after 48 hours and 12 weeks aging in distilled water.

Results: Permasoft had higher solubility (1.50% +/- 0.20% laboratory-processed and 1.42% +/- 0.16% autopolymerized at chairside) and sorption (2.45% +/- 0.36% laboratory-processed and 1. 76% +/- 0.08% autopolymerized at chairside) than Luci-sof (0.17% +/- 0.09% solubility and 0.41% +/- 0.17% sorption) after 6 weeks of aging. For tensile bond strength, there was no significant difference between each respective control and the 12-week bond strength for each material. However, Luci-sof (1.16 +/- 0.27 MPa) had a significantly higher tensile bond strength than Permasoft (0. 50 +/- 0.18 MPa laboratory-processed and 0.44 +/- 0.09 MPa autopolymerized at chairside).

Conclusion: On the basis of lower water sorption and solubility and higher tensile bond strength, Luci-sof may provide better clinical success.