Evaluation of some physical properties of the Acropars soft liner and Molloplast-B Dr. Geramipanah F.,1 Dr. Namdar F.,2 Dr. Sedighpour L.3 1Associate Professor, Prosthetic Dentistry Department, Faculty of Dentistry. Dental Research Center Tehran University / Medical Sciences, Tehran, Iran. 2Dentist, Private Practice, Tehran, Iran. 3Assistant Professor. Prosthetic Dentistry Department, Faculty of Dentistry, Tehran University / Medical Sciences, Tehran, Iran. Abstract Background & Aim: To date no product is available that have all the desirable properties of an ideal resilient material. Therefore, it is necessary to determine certain physical and mechanical properties of new soft liner materials that are introduced in the market. The aim of this study was to investigate several properties of Acropars compared to Molloplast B. Materials & Methods: Two groups of permanent resilient liner materials, a heat cured acrylic copolymer (Acropars Marlik Medical Inc., Iran) and silicone based rubber (Molloplast B Detax Ettlingern, Germany), were tested for hardness, elongation percentage, tensile and tear strengths.Ten dumbbell-shaped specimens were fabricated for each test group according to ASTM-D412 (Die-c) and ASTM-D638 (type 4) standards. The universal testing machine was used to test all specimens for tensile strength, elongation percentage. Ten cylinder shaped specimens of 31 × 10 mm (in diameter and height) were prepared for hardness test. This test was conducted, using a shore-A hardness instrument, according to ASTM-D2240 standards. Also the standard test method of ASTM-D624 for tear resistance of rubber material was performed. Ten bar shaped specimens of 60×10×2 mm, with a 45 degrees notch 6 mm in width on lower side were prepared. All specimens were forced to failure using a universal testing machine. All specimens were stored at room temperature for 40 hours before testing process started. The mean group differences and student-t test at α= 0.05 were used for statistical data analysis. Results: Acropars showed statistically significant greater mean tensile strength (P<0.0001), tear strength (P<0.0001) and hardness (P<0. 0001) compared to Molloplast B. In addition Molloplast B showed a significant higher elongation percentage. (Pv<0.001) Conclusion: Within the limits of the present study, it was demonstrated that Acropars had higher tensile and tear strength, but harder than Moloblast B. Key words: Resilient liners - soft liners - physical properties – hardness - tensile strength - tear strength - elongation percentage – Acropars - Molloplast B. Corresponding Author: Dr. Sedighpour L., Prosthetic Dentistry Department, Faculty of Dentistry, Tehran University / Medical Sciences,Tehran, Iran. e.mail: sedighle@tums.ac.ir |
