[Determination of residual monomer content in Acropars samples by Fourrier Transform Infrared method]

Acrylic resins possess many desirable properties, but it is possible that the denture bases contain residual monomer, which may cause some side effects such as hypersensitivity of oral tissues and altered characteristics of acrylic resin. The purpose of this study was to measure the residual monomer in heat cure Acropars[R] acrylic resin and comparison of these results with ISO standard. This study was an experimental research which was performed according to ISO 1567 standard. At first, five solutions of MMA monomer in MIBT, as the solvent, were produced with concentrations of 0.1, 0.2, 0.3, 0.4 and 0.5 weight percents for which Fourier Transform Infrared [FTIR] spectra were obtained. The calibration curves were then prepared based on these five known samples. As unknown samples, four disks of Acropars acrylic resin with diameter of 50 mm and thickness of 3 mm were provided and were dissolved in MIBT. After the swelling of samples and therefore the releasing of monomer in the solvent, the solutions were characterized by FTIR analysis. Concentration of monomer in solution was assessed by calibration curves. Data were statistically analyzed using t-student test [alpha=0.05]. The average level of residual monomer in Acropars samples was 0.428 weight percent. The level of residual monomer in Acropars samples met the requirements of ISO standard. The difference between the mean concentration of Acropars residual monomer and ISO standard was positively significant [p<0.05]

[Comparison of wear between Iranian resin teeth and ivoclar teeth]

Wearing of acrylic denture teeth creates many problems for patients as well as dentists. Nowadays, artificial teeth are produced by different Iranian companies which compare to their foreign counterparts are more suitable economically. The aim of this study was to compare the amount of wear between Iranian resin teeth and Ivoclar teeth. In this study wear of three types of Iranian resin teeth [Berelian. Marjan, Super newclar] were compared with Ivoclar teeth. Four denture teeth samples were used for each denture teeth. All tests were done in presence of saliva and by using porcelain abrader. The thickness reduction of each sample was measured after 5000 and 10000 cycles with the help of a micrometer. The mean values were compared with ANOVA and T-student test. After 5000 and 10000 cycles there was no significant difference between the mean wear of Berelian teeth and Ivoclar teeth, but after 10000 cycles the mean wear of Ivoclar teeth was decreased and the mean wear of Berelian teeth was increased although this wear was not statistically significant. Comparison of three Iranian resin denture teeth indicated that Berelian teeth showed the least and Super newclar teeth show the maximum amount of wear. The amount of wear in Berelian was almost close to Ivoclar teeth. Therefore we can be hopeful that Iranian companies with improving their production techniques such as mixing the materials, temperature, duration of curing and packing of materials in vacuum can make high wear resistance acrylic teeth