323 A comparison of the diametral tensile strength(D.T.S) of Fuji Type II and S.D.S glass ionomer cements(In-Vitro study)

Diametral tensile strength is a property of brittle restorative materials and cements like glass ionomers. Being an adequate and standard amount of this characteristic is necessary for obtaining clinically acceptable results in their use. According to the lack of reports about S.D.S glass ionomer cement that recently has been introduced to Iranian market, this study was conducted with the aim of comparing of the diametral tensile strength(D.T.S) of Fuji Type II and restorative S.D.S glass ionomer cements in different periods of time. This experimental study was performed on 20 disk shaped specimens of each cement; they were prepared according to ANSI / ADA 66 specification (9 mm diameter and 4/5 mm length).The ratios of powder to liquid meticulously followed manufacturers recommendations for use. All specimens were holded in an incubator at 37±1ºc and 95±5% relative humidity prior to testing. each group of cements were tested in two periods of time after the beginning of mixing (15minute and 24hours) in a universal testing machine (Zwick Roell- Germany Z020) at a crosshead speed of 0/5 mm/min. The test results were analyzed by One-Sample Kolmogorov- Smirnov Test and T Test. Mean values of diametral tensile strength of FT II in 15minute and 24hours, were 5/67 MPa and 6/98 MPa and for restorative S.D.S cement were 4/54 MPa and 6/61 MPa respectively. Statistical analysis revealed that there was no significant difference between diametral tensile strength of these two cements at 15 minute and 24 hours, but D.T.S had an increase during time which was statistically significant in both cements.