Effects of filler composition on flexibility of microfilled resin composite

Abstract

The effects of the filler composition on physical and mechanical properties of microfilled composites was investigated by measuring water absorption, solubility, compressive, flexural, and impact strength. A series of experimental composites, consisting of UDMA/TEGDMA comonomer matrix and prepolymerized fillers, was fabricated. The prepolymerized fillers were composed of hydrophobic colloidal silica and two monomers in varying ratios, trimethylolpropanetrimethacrylate (TMPT), and polyesterdiacrylate (PEDA). TMPT/PEDA ratios were 100:0, 64:36, 46:54, 18:82, and 0:100%. There were no significant differences in water sorption and solubility, regardless of the amount of PEDA monomer. Young's modulus and modulus of resilience increased with decreasing PEDA ratio. Fracture energy exhibited drastic changes (30.1 x 10(-5) J to 93.4 x 10(-5) J). The highest value of flexural strength (96.0 +/- 3.5 MPa) was obtained when the TMPT-PEDA filler was 46:54. The impact strengths of composites fabricated with TMPT-PEDA filler of 46:54 (11.2 +/- 1.4 kJ/m(2)), 18:82 (10.6 +/- 3.2 kJ/m(2)), and 0:100 (13.1 +/- 3.8 kJ/m(2)) were significantly higher than those with 100:0 (6.0 +/- 1.8 kJ/m(2)) or 64:36 (7.1 +/- 2.4 kJ/m(2)). Based upon the results, it was concluded that the mechanical properties of microfilled composites were improved by the modification of prepolymerized filler composition.

Effect of thermocycling on the bond strength of composite resin to bur and laser treated composite resin

“…Several changes occur to resin-based composites during the aging process that can influence the success of the repairing procedure, such as water sorption, chemical degradation, and leaching out of some constituents [6,36,37]. On this account, the age of the restoration to be repaired plays a fundamental role in the bond strength of composite repairs [18].…”

An In Vitro Assessment of the Effects of Three Surface Treatments on Repair Bond Strength of Aged Composites

“…5,9 In the mouth, absorption of water by diffusion through the resin phase of composites will affect the ability of the new composite to adhere to the aged composite, because the number of available unsaturated double bonds diminishes with aging. 10 The shear bond strength (SBS) of fresh composite to the composite aged in water or contaminated with artificial saliva has been studied previously. [11][12][13] In these studies, various methods have been suggested for establishing satisfactory SBS levels between the existing composite and the fresh one: mechanical grinding, acid etching, resin coating, or a combination of these treatments.…”

Effect of surface treatments on the tensile bond strength of repaired water-aged anterior restorative micro-fine hybrid resin composite

“…3,4 Several changes occur to resin-based composites during aging process which could influence of the success of repairing procedure such as water sorption, chemical degradation and leaching out of some their constituents. [5][6][7] If adequate bonding between the old resinbased composite and freshly added bonding resin could be achieved, the repair of the existed old restorations becomes an attractive solution. 4 Many researches [8][9][10][11] studied the relevance of various chemical and/or mechanical treatments of aged resin-based composites on the repair bond strength.…”