A comparative evaluation of effect on water sorption and solubility of a temporary soft denture liner material when stored either in distilled water, 5.25% sodium hypochlorite or artificial saliva: An in vitro study

Abstract

Introduction:Soft denture liners have a key role in modern removable prosthodontics since they restore health to inflamed and abused mucosa by redistribution of forces transmitted to the edentulous ridges. The most common problems encountered using soft denture liners are water sorption and solubility when in contact with saliva or storage media. These problems are associated with swelling, distortion, support of Candida albicans growth, and stresses at the liner/denture base interface that reduces the bond strength.Objective:To evaluate the water sorption and solubility of commercially available acrylic based self cure soft denture lining material (GC RELINE™ Tissue Conditioner) after immersion in three different storage media (distilled water, Shellis artificial saliva, 5.25% sodium hypochlorite disinfectant solution) at time interval of 4, 7, 11, and 15 days.Material and Methods:The study involved preparation of artificial saliva using Shellis formula. A total 45 standardized samples of the material (GC RELINE™) were prepared in disk form (15 mm in diameter and 2 mm in thickness). The study was divided into three groups with storage in Control (distilled water), Shellis artificial saliva, and 5.25% sodium hypochlorite. Samples were dried in a desiccator and weighed in the analytical balance to measure the initial weight (mg/cm2) of the disks (W1). The first groups (15 samples) were placed in 30 ml distilled water (Group A) at 37ºC, second group 30 ml of artificial saliva (Group B) and third group in 5.25% sodium hypochlorite (Group C). Disks were removed from disinfectant after 5 min and placed in 30 ml distilled water. On days 4, 7, 11, and 15, all samples were removed from their containers and reweighed to measure the weight (mg/cm2) of the disks after sorption (W2). The solubility was measured by placing the disks back in the desiccator after each sorption cycle and drying them to constant weight in the desiccator. These values were weight after desiccation (W3). Water sorption and solubility was calculated: 1. Sorption (mg/cm2) = (W2−W1)/Surface area 2. Solubility (mg/cm2) = (W1−W3)/Surface area.Statistical Analysis:Statistical Analysis was done using one way analysis of variance and the intercomparison between each group was done using Tukey's honestly significance difference (HSD) test.Results:Within the limitations of this study it was concluded that water sorption of the GC RELINE™ soft denture liner material was highest in distilled water followed by 5.25% sodium hypochlorite and least in Shellis artificial saliva at 4, 7, and 11 day interval. However, on the 15th day, the results showed maximum water sorption in 5.25% sodium hypochlorite followed by distilled water and least in artificial saliva. The results on solubility showed highest solubility of GC RELINE soft denture liner in artificial saliva followed by distilled water and least in 5.25% sodium hypochlorite at 4, 7, 11, and 15 day interval.Discussion:The least water uptake of the soft liner in artificial saliva was due to its ionic properties...

Effect of Alcohol and Tea on Solubility of Soft-liner and Polymethyl Methacrylate Resin: An In Vitro Study

“…Similar finding of increased solubility of soft-liner in artificial saliva was reported by Garg et al6 …”

“…Leaching of plasticizer causes loss of mass and an increase in solubility. 6 The result of this comparative evaluation on solubility showed that on day 4 mean solubility of soft denture lining material across groups was statistically different (p <0.001). On pairwise comparison, it was found that mean solubility of samples immersed in tea with milk and green tea was significantly higher than that of groups A to C. similarly mean solubility was different at day 7 as well.…”

“…Solubility studies in different liquids/storage media such as artificial saliva, denture cleansers, and disinfectant solutions were reported by various researchers. 3,6,14 In study by Kazanji et al solubility of soft-liner in artificial saliva was found to be increased after one month. 14 15 Safari et al tested the effect of 8% and 50% alcohol on hardness and tensile bond strength of soft-liner to the acrylic resin and found no significant interaction.…”

“…Soft lining material undergoes two processes when immersed in water one is leaching of plasticizer and soluble compounds in water and absorption of water. 6,12 When immersed in water it exerts a significant effect on properties of the polymer. Water ingresses through diffusion and enters to occupy space between polymer chains.…”

“…Water sorption and solubility, thus, are problems that are commonly encountered when using soft denture liners. [5][6][7][8][9] These problems are associated with changes in structure and properties of the material that results in swelling, distortion, support of Candida albicans growth, reduced bonding to the denture base, and a hard, less resilient product over time. 5,9 The aim of this study is to evaluate solubility of soft denture liner material and acrylic denture base resin when stored in 8% and 50% concentration of alcohol and tea(with milk and green tea) at an interval of 4, 7, 11 and 15 days.…”