A comparative evaluation of properties of denture base materials processed with different processing methods: a preliminary study.

Background: The use of the traditional polymerization process of dentures necessitates a lot of time and energy. To depreciate these factors, a different processing method could be studied. Aim: This study was aimed to evaluate and compare the properties of denture base resin material processed with conventional curing and pressure-pot method. Materials and methods: A total of 30 specimens with distinct dimensions were fabricated with the denture base materials. The specimens were divided into two groups with 15 each, and they were processed using conventional heat-curing and pressure-pot processing, respectively. Each group is subdivided into three groups with five specimens in each for evaluating flexural strength, water sorption, and residual monomer, respectively. Flexural strength was measured using a 3-point bending test with a Universal testing machine. Water sorption was assessed by measuring the weight of the specimens after immersing them in distilled water. Residual monomer content was evaluated using a UV spectrophotometer.  The obtained data were statistically analysed using an independent t-test. Results: A slight increase in flexural strength was observed in the pressure processed specimens. However, no significant differences (p=0.131) were observed in the flexural strength between the groups. Less water sorption percentage was observed with the pressure processed acrylic resin specimens, and a significant difference (p=0.047) was observed between the groups. A slightly more amount of residual monomer content was seen in the acrylic specimens processed conventionally. Conclusion: Pressure-pot curing may be used for processing denture base acrylics as it provides properties similar to that of the conventional curing method

Evaluation of marginal gap of Ni-Cr copings made with conventional and accelerated casting techniques

Context: Conventional casting techniques following the manufacturers′ recommendations are time consuming. Accelerated casting techniques have been reported, but their accuracy with base metal alloys has not been adequately studied. Aim: We measured the vertical marginal gap of nickel-chromium copings made by conventional and accelerated casting techniques and determined the clinical acceptability of the cast copings in this study. Settings and Design: Experimental design, in vitro study, lab settings. Materials and Methods: Ten copings each were cast by conventional and accelerated casting techniques. All copings were identical, only their mold preparation schedules differed. Microscopic measurements were recorded at ×80 magnification on the perpendicular to the axial wall at four predetermined sites. The marginal gap values were evaluated by paired t test. Results: The mean marginal gap by conventional technique (34.02 μm) is approximately 10 μm lesser than that of accelerated casting technique (44.62 μm). As the P value is less than 0.0001, there is highly significant difference between the two techniques with regard to vertical marginal gap. Conclusion: The accelerated casting technique is time saving and the marginal gap measured was within the clinically acceptable limits and could be an alternative to time-consuming conventional techniques