Showing 3 results for Ebadian
B. Ebadian, Ma. Parkan ,
Volume 15, Issue 3 (8 2002)
Abstract
One of the most important characteristics of denture base is thermal conductivity. This property has a major role in secretions of salivary glands and their enzymes, taste of the food and gustatory response. Polymethyl methacrylate used in prosthodontics is relatively an insulator. Different materials such as metal fillers and ceramics have been used to solve this problem. The aim of this study was the evaluation of AI2O3 effect on thermal conductivity of heat-cured acrylic resin. Acrylic resin was mixed with AI2O3 in two different weight rates (15 and 20 % of weight). So, group 1 and 2 were divided on this basis. Samples with pure acrylic resin were considered as control group. 18 cylindrical patterns were made in 9x9 mm dimensions and thermocouple wires embedded in each sample to act as conductor. The specimens were put in water with 70±1°C thermal range for 10 minutes. Then, thermal conductivity was measured. The results were analyzed with variance analysis and Dunken test. There was significant difference between thermal conductivity of all groups in all period times. It the first seconds, thermal conductivity in groups 1 and 2 were more than control group. Therefore, for developing of thermal conductivity of acrylic resin, A1203 can be used. Certainly, other characteristic of new resin should be evaluated.
B. Ebadian , Ma. Bazargan Zadeh ,
Volume 16, Issue 2 (8 2003)
Abstract
Statement of Problem: The construction of dental materials has been developing inside the country.Cold- cured acrylic resins are of such materials which are used in removable prostheses.
Purpose: The aim of this study was to compare the dimensional changes of two types of cold-cured acrylic resins, Acropars and Meliodent.
Material and Methods: Forty acrylic discs, with diameter of 13.7 mm, were made of Acropars and Meliodent acrylic resins (20 samples in each group). Then, each group was randomly divided into two parts. The first group was kept in usual environment, whereas the samples of the second group were placed in the boiling water for five minutes. The dimensional changes of the samples, at different intervals and seven days post curing, were measured by light microscope and recorded. Variance analysis was used to analyze the results.
Results: Acropars resins, comparing to Meliodent ones, showed a considerable dimensional changes,which was statistically significant. Boiling of Acropars resins, for five minutes, lead to a significant shrinkage. The maximum shrinkage occured at 24 hours post curing.
Conclusion: If the tray is made of Acropars acrylic resin, it is recommended to take impression, 24 hours
after its setting.
B. Ebadian , R. Mosharaf , M. Ebrahimi ,
Volume 16, Issue 4 (9 2004)
Abstract
Statement of Problem:Iranian product, Acropars autopolymerizing acrylic resin is nowadays widely used in dental prostheses. Dimensional change is a common problem among Iranian made acrylic resins in making custom trays and record bases, seems to be more than the similar foreign products. In order to achieve a technique for making a record base with minimum dimensional changes, more research is necessary.
Purpose: The aim of the present study was to determine a curing technique for Iranian autopolymerizing acrylic resins leading to the least polymerization shrinkage and the most adaptation between record bases and stone casts.
Materials and Methods: In this experimental study, 40 stone casts were divided into four 10- member group. For each group, polymerization shrinkage was determined at three points with one of the following techniques: Bench curing, Curing under a coat of petroleum jelly , Curing in a monomer saturated atmosphere, Curing in boiled water. Adaptation between bases and stone casts were measured at three points (the right and left crests of the ridge and the midpalatal region) with a light-measuring microscope. To analyze
the data, Variance analysis was used.
Results: The monomer atmosphere technique showed the minimum dimensional changes and the samples in boiled water group had the maximum dimensional changes. No statistical differences were observed between other groups.
Conclusion: More adaptation between record bases and stone casts was observed in monomer atmosphere polymerization technique. The differences between bench curing and curing under a coat of petroleum jelly techniques with this method were not statistically significant. Therefore, it is suggested for making base records with maximum adaptation.
