Physical Properties of Modern Filling Composites

Objectives: Good physical properties of filling materials are essential for the longevity of final restorations. A filling material has to suffer different stresses and strains and therefore it is necessary that it shows good results not only in one but in any mechanical test. This study compares different composite systems and shows their physical properties.

Methods: The materials studied were: Clearfil Majesty^TM Posterior (CM, Kuraray), Tetric^® Evo Ceram (TEC, Ivoclar Vivadent), Filtek^TM Supreme XT (FS, 3M Espe), Filtek^TM Siloran (SI, 3M Espe) and an experimental composite (EC, VOCO). The specimens for flexural strength and modulus of elasticity were prepared and measured according to ISO 4049. The measurements were executed with a universal testing machine Zwick version 1446. Volumetric shrinkage was executed on a dilatometer according to a standard ACTA method (J. Prosthet. Dent. 59, 1988, 297-300). The wear measurements were executed on a Willytec testing device according to an ACTA method (J. Dent. Suppl. 1, 22, 1994, 21-27) and were analysed with a Laserscan 3D (Willytec). Data were tested by one-way ANOVA followed by Duncan's multiple analysis on the .05 level.

Results:

	CM	TEC	FS	SI	EC
Flexural strength [MPa]	162.0±14.1b	128.7±4.4d	144.3±6.3c	116.0±7.6e	187.7±9.8a
Modulus of elasticity [GPa]	20.06±0.53a	8.57±0.19e	11.24±0.27c	10.32±0.59d	16.01±0.83b
Volumetric shrinkage [%]	1.62±0.11b	2.08±0.07c	2.46±0.07d	1.45±0.07a	1.64±0.08b
Wear [µm]	23.0±3.4a	44.1±2.9b	22.7±3.5a	69.6±5.0c	22.2±4.7a

EC showed statistically significant the best results in flexural strength and together with CM and FS in wear measurements. SI showed the best results in volumetric shrinkage while CM had the highest modulus of elasticity. EC and CM showed the best accordance to human dentin's modulus of elasticity found in literature.

Conclusion: Overall this study demonstrates superior properties for the high-filled (filler content ³90% by weight) nanohybrid composites CM and EC, especially compared to the shrinkage-optimized Filtek^TM Siloran.