A Alrahlah1, N Silikas2, D C Watts2. 1. Biomaterials Research Group, School of Dentistry, University of Manchester, Manchester M13 9PL, UK; Department of Restorative Dentistry, College of Dentistry, King Saud University, Riyadh, Saudi Arabia. Electronic address: alrahlah@hotmail.com. 2. Biomaterials Research Group, School of Dentistry, University of Manchester, Manchester M13 9PL, UK.
Abstract
OBJECTIVE: To evaluate the extent and rate of hygroscopic expansion of resin composites at 37°C. METHODS: Eight resin composites were examined: 1 micro-hybrid (Bright Light(®)), 5 nano-hybrids (Experimental Vertise™; Nanoceram-Bright(®); Tetric EvoCeram(®); Grandio(®) SO; Ceram X™ duo) and 2 flowables (X-tra base; Venus(®) Diamond Flow). Five disks (15 mm×2 mm) of each material were prepared. The mean change in specimen diameter was recorded by a custom-built non-contact laser micrometer. Specimens were initially measured dry and then at fixed time intervals, over 150 days, after storage in distilled water at 37±1°C. Data were re-expressed in volumetric terms and analysed by repeated measures ANOVA, one-way ANOVA and Tukey's post hoc test (α=0.05). RESULTS: The volumetric hygroscopic expansion ranged from 0.58 to 2.26 and can be considered in three bands. First, Experimental Vertise had the highest expansion (p<0.001). Venus Diamond Flow, Tetric EvoCeram and Ceram X duo were the second band. The third band, with still lower expansion, consisted of Bright light, Grandio So, Nanoceram-Bright and X-tra base, with no significant difference between them. CONCLUSION: For the size (2mm thickness) and shape of specimen measured, equilibrium was attained in all cases by 60 days. Within this set of resin-composites the equilibrium expansion varied by almost 400% of the lowest material.
OBJECTIVE: To evaluate the extent and rate of hygroscopic expansion of resin composites at 37°C. METHODS: Eight resin composites were examined: 1 micro-hybrid (Bright Light(®)), 5 nano-hybrids (Experimental Vertise™; Nanoceram-Bright(®); Tetric EvoCeram(®); Grandio(®) SO; Ceram X™ duo) and 2 flowables (X-tra base; Venus(®) Diamond Flow). Five disks (15 mm×2 mm) of each material were prepared. The mean change in specimen diameter was recorded by a custom-built non-contact laser micrometer. Specimens were initially measured dry and then at fixed time intervals, over 150 days, after storage in distilled water at 37±1°C. Data were re-expressed in volumetric terms and analysed by repeated measures ANOVA, one-way ANOVA and Tukey's post hoc test (α=0.05). RESULTS: The volumetric hygroscopic expansion ranged from 0.58 to 2.26 and can be considered in three bands. First, Experimental Vertise had the highest expansion (p<0.001). Venus Diamond Flow, Tetric EvoCeram and Ceram X duo were the second band. The third band, with still lower expansion, consisted of Bright light, Grandio So, Nanoceram-Bright and X-tra base, with no significant difference between them. CONCLUSION: For the size (2mm thickness) and shape of specimen measured, equilibrium was attained in all cases by 60 days. Within this set of resin-composites the equilibrium expansion varied by almost 400% of the lowest material.
Authors: Kanokrat Kangwankai; Sarah Sani; Piyaphong Panpisut; Wendy Xia; Paul Ashley; Haralampos Petridis; Anne Margaret Young Journal: PLoS One Date: 2017-11-14 Impact factor: 3.240