Matej Par1, Zrinka Tarle2, Reinhard Hickel3, Nicoleta Ilie3. 1. Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, Augusta Cesarca 10, 10000, Zagreb, Croatia. mpar@inet.hr. 2. Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, Augusta Cesarca 10, 10000, Zagreb, Croatia. 3. Department of Restorative Dentistry, Periodontology and Pedodontics, Ludwig-Maximilians-University of Munich, Goethestr. 70, Munich, Germany.
Abstract
OBJECTIVES: To evaluate the effect of bioactive glass 45S5 (BG) in experimental composites on flexural strength (FS), flexural modulus (FM), modulus of resilience (MR), and material reliability after artificial aging in water for 1, 7, and 30 days, and an additional accelerated aging for 3 days in a 75 vol% ethanol-water solution. MATERIALS AND METHODS: Five experimental light-curable composites were prepared with 0-40 wt% of BG and a total filler load of 70 wt%. The resinous matrix was Bis-GMA/TEGDMA in 60:40 by weight. Mechanical properties were evaluated using a three-point bending test (ISO/DIN 4049:1998) with n = 20. Weibull statistics were used to assess material reliability. Additionally, the degree of conversion (DC) was assessed 24 h post-cure using FT-Raman spectroscopy. RESULTS: FS and FM decreased linearly as the amount of BG was increased. The ISO 4049 requirement for a minimum FS of 80 MPa was fulfilled in experimental composites with up to 20 wt% of BG. Degradation of FS and FM with artificial aging was more extensive in materials with higher BG amounts. MR decreased as a function of BG amount and artificial aging. Material reliability (Weibull modulus) was stable through aging for composites with up to 10 wt% of BG. DC was negatively influenced by the BG amount and ranged from 64 to 81%. CONCLUSION: Increasing the amount of unsilanized BG fillers from 0 to 40 wt% resulted in a progressive decline in mechanical properties and a more extensive degradation during artificial aging. CLINICAL RELEVANCE: Bioactive fillers diminished the mechanical properties in a dose-dependent manner.
OBJECTIVES: To evaluate the effect of bioactive glass 45S5 (BG) in experimental composites on flexural strength (FS), flexural modulus (FM), modulus of resilience (MR), and material reliability after artificial aging in water for 1, 7, and 30 days, and an additional accelerated aging for 3 days in a 75 vol% ethanol-water solution. MATERIALS AND METHODS: Five experimental light-curable composites were prepared with 0-40 wt% of BG and a total filler load of 70 wt%. The resinous matrix was Bis-GMA/TEGDMA in 60:40 by weight. Mechanical properties were evaluated using a three-point bending test (ISO/DIN 4049:1998) with n = 20. Weibull statistics were used to assess material reliability. Additionally, the degree of conversion (DC) was assessed 24 h post-cure using FT-Raman spectroscopy. RESULTS: FS and FM decreased linearly as the amount of BG was increased. The ISO 4049 requirement for a minimum FS of 80 MPa was fulfilled in experimental composites with up to 20 wt% of BG. Degradation of FS and FM with artificial aging was more extensive in materials with higher BG amounts. MR decreased as a function of BG amount and artificial aging. Material reliability (Weibull modulus) was stable through aging for composites with up to 10 wt% of BG. DC was negatively influenced by the BG amount and ranged from 64 to 81%. CONCLUSION: Increasing the amount of unsilanized BG fillers from 0 to 40 wt% resulted in a progressive decline in mechanical properties and a more extensive degradation during artificial aging. CLINICAL RELEVANCE: Bioactive fillers diminished the mechanical properties in a dose-dependent manner.