Depth of Cure, Surface Characteristics, Hardness, and Brushing Wear of 4 Direct Restorative Materials in Paediatric Dentistry

Aim: The study aimed to compare the depth of cure, hardness, surface roughness, and wear resistance of four restorative materials used in pediatric dentistry: FUJI IX GP FAST, RivaSilver, SDR flow+, and Vertise Flow. Materials and Methods: The depth of cure was measured per ISO 4049 standards using a digital caliper, with 15 samples of each material. Hardness was evaluated using a Vickers indenter under a 10 N load for 20 s. Surface roughness was assessed before and after acid exposure using an optical profilometer according to ISO 4288. Brushing wear resistance was analyzed by subjecting samples to 20 and 60 min of brushing, followed by roughness measurements. Statistical analysis was performed using independent sample t-tests to determine the significance of differences between the materials, with p-values < 0.05 considered significant. Results: SDR flow+ exhibited the highest depth of cure with an average of 3.5 mm (+/- 0.2 mm), significantly higher than Vertise Flow at 2.8 mm (+/- 0.3 mm) (p < 0.001). Hardness testing revealed SDR flow+ had the highest average hardness (85 HV +/- 4 HV), while Vertise Flow had the lowest (72 HV +/- 5 HV) (p < 0.001). Surface roughness increased significantly after acid exposure for RivaSilver (from 1.2 mu m +/- 0.12 mu m to 1.6 mu m +/- 0.15 mu m, p = 0.007) and for SDR flow+ (from 0.85 mu m +/- 0.08 mu m to 1.3 mu m +/- 0.14 mu m, p = 0.001). Brushing wear resistance was highest in RivaSilver (Ra increase from 1.2 mu m to 1.4 mu m +/- 0.11 mu m) and lowest in FUJI IX GP FAST (Ra increase from 1.5 mu m to 1.9 mu m +/- 0.15 mu m, p < 0.001). Conclusions: The study demonstrates significant differences in performance among the tested materials. SDR flow+ showed a superior depth of cure and hardness, making it suitable for high-stress applications. However, all materials displayed increased surface roughness following acid exposure and brushing, with FUJI IX GP FAST showing the highest wear. These findings highlight the need to select restorative materials based on the specific clinical demands of pediatric patients, considering both their mechanical properties and resistance to wear and acid.