The comparison of relative reliability on biaxial and three point flexural strength testing methods of light curing composite resin

Abstract

The possibility of applying a bi-axial flexure strength test on composite resin was examined using three point and bi-axial flexure strength tests to measure the strength of the light-cured resin and to compare the relative reliability using the Weibull modulus.The materials used in this study were light-curing restorative materials, MICRONEW TM , RENEW � (Bisco, Schaumburg, USA). The bi-axial flexure strength measurements used the piston-on-3-ball test according to the regulations of the International Organization for Standardization (ISO) 6872 and were divided into 6 groups, where the radius of the specimens were 12 ㎜ (radius connecting the 3-balls: 3.75 ㎜), 16 ㎜ (radius connecting the 3-balls: 5 ㎜), and the thickness were 0.5 ㎜, 1 ㎜, 2 ㎜ for each radius.The bi-axial flexure strength of the MICRONEW TM and RENEW � were higher than the three point flexure strength and the Weibull modulus value were also higher in all of the bi-axial flexure strength groups, indicating that the bi-axial strength test is relatively less affected by experimental error.In addition, the 2 ㎜ thick specimens had the highest Weibull modulus values in the bi-axial flexure strength test, and the MICRONEW TM group showed no significant statistical difference (p > 0.05). Besides the 2 ㎜ MICRONEW TM group, each group showed significant statistical differences (p < 0.05) according to the thickness of the specimen and the radius connecting the 3-balls.The results indicate that for the 2 ㎜ group, the bi-axial flexure strength test is a more reliable testing method than the three point flexure strength test. [J Kor Acad Cons Dent 31(1): [58][59][60][61][62][63][64][65] 2006]

Effect of Two Polishing Systems on Surface Roughness, Topography, and Flexural Strength of a Monolithic Lithium Disilicate Ceramic

“…Several factors influence the measurement of flexural strength such as the testing method, specimen dimensions, testing environment, polishing procedures, stress rates, and stress area. 39,40 Other than polishing procedures with D+Z and OptraFine systems, no other differences were found between the two groups with respect to the abovementioned factors. Finer diamond particles of the polishing paste of the OptraFine system may result in shallower scratches and fewer surface flaws, cracks, porosities, and irregularities.…”

“…Moreover, the flexural strength of the grinding‐D+Z group was measured to be significantly lower than that of grinding‐OptraFine group. Several factors influence the measurement of flexural strength such as the testing method, specimen dimensions, testing environment, polishing procedures, stress rates, and stress area . Other than polishing procedures with D+Z and OptraFine systems, no other differences were found between the two groups with respect to the abovementioned factors.…”

Flexural strength and microstructure of two lithium disilicate glass ceramics for CAD/CAM restoration in the dental clinic

“…Our data obtained from IPS e.max CAD were relatively higher than the values claimed by the manufacturers. It has been reported that the biaxial flexure test tends to yield higher values than the 3-point flexure test 10. Our data were close to the results reported by Buso et al and Lin et al [mean flexural strength (SD) of 416.1 (50.1) MPa and 365.1 (46.0) MPa], which had been obtained from specimens of a similar size and shape to ours and by a similar method 3,11.…”

The comparisons of layers and the effect of additional firings on flexural strength and translucency of 5Y-ZP

“…Biaxial flexural strength test does not show edge failure and the effect of crack direction is minimal, and therefore, is considered more accurate than uniaxial flexural strength. 27,28 Thus, the flexural strength was measured using biaxial test and approximately 650 to 750 MPa was measured in groups without additional firing. The result was similar to the flexural strength of another pre-shaded 5Y-ZP reported by Kwon et al 14 Although the 5Y-ZP showed a lower flexural strength than that of 3Y-TZP due to the lack of transformation toughening, it yielded higher flexural strength than lithium disilicate.…”