Purpose:This in vitro study was done to compare the flexural strength of polymethyl methacrylate resin reinforced with multiwalled carbon nanotubes (MWCNTs) and processed by conventional water bath technique and using microwave energy.Materials and Methods:A total of 180 acrylic resin specimens measuring 65 mm × 10 mm × 2.5 mm were fabricated, with conventional water bath groups and microwave group having ninety specimens each. Ninety specimens were divided into thirty specimens as control and subgroups containing 0.025% MWCNTs and 0.050% MWCNTs with thirty specimens each. The specimens were tested for flexural strength by three-point bending test on universal testing machine. The statistical analysis was done using Student's t-test and one-way analysis of variance, and the intercomparison between each group was done using Tukey's post hoc analysis.Results:The mean flexural strength of specimens cured by water bath technique was 95.563 MPa and microwave technique was 118.416 MPa. Control Group B possesses highly significant increase in flexural strength than Control Group A with P < 0.01. Unpaired Student's t-test showed that Subgroup B1 and Subgroup B2 possess highly significant increase in flexural strength than Subgroup A1and Subgroup A2.Conclusion:Heat polymerized denture base resin with and without reinforcement of MWCNTs and polymerized by microwave technique possess higher flexural strength than heat polymerized fiber reinforced denture resin polymerized by water bath technique. MWCNTs could be used as an effective reinforcement material for denture base resin polymerized by either water bath technique or microwave energy.

Aim: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. Materials and methods:An in vitro study wasdone on 75 standardized samples in disk form (15 mm × 2 mm), each for soft-liner and acrylic denture base resin. Samples were divided into 5 groups (15 per group/per material) and stored in distilled water (A), 8% alcohol (B), 50% alcohol (C), tea with milk (D) and green tea (E). Solubility was determined at each time interval by dividing difference of weight (taken after drying the sample in a desiccator) from day 1 divided by surface area of the specimen. For each day (i.e., 4, 7, 11 and 15),one-way analysis of variance (ANOVA) test was used to determine if the distribution of mean solubility was similar in five groups followed by post-hoc Tukey's test for pair-wise comparisons.Results: Mean solubility of soft-liner was the highest tea with milk (D) followed by green tea (E), then 50% and 8 % alcohol (C and B) and was least in group A at each time of measurement. Mean solubility of an acrylic resin was highest for 8% alcohol (B) and all other groups it was similar. Conclusion:This study shows increased solubility for softliners when immersed in tea with milk, green tea, and alcohol at 8% and 50% concentration. The solubility of acrylic resin also increases at 8% alcohol concentration.Clinical significance: Drinks/beverages used in our study are commonly consumed, the results of this study caution for restricting the frequency of intake. However, this needs to be confirmed by in-vivo studies designed to prove the association of denture life with the consumption pattern of these drinks/ beverages.