Color stability, surface roughness and surface morphology of universal composites

MENIAWI, M (2024). Color Stability, Surface Roughness and Surface Morphology of Universsal Composites, Yeditepe University, Institute of Health Science, Department of Restorative dentistry, PhD thesis, Istanbul. Objectives: This in vitro study aimed to evaluate the color stability, surface roughness (Ra; µm), and surface morphology of universal composites after exposure to discoloring agents over a period of 21 days. Materials and Methods: A total of 200 cylindrical composite discs (n=40 from each); supra nano-fill Estelite Asteria (EA; Tokuyama, Japan), nano-hybrid G-aenial A'chord (GA; GC, Japan), nano-hybrid G-aenial Universal Injectable (GI; GC, Japan), nano-fill Filtek Universal (UF; 3M. USA) and nano-fill Filtek Ultimate (FU; 3M, USA) were prepared and polymerized (Bluephase N; Ivoclar, USA). Following storage in distilled water for 24 h at 37°C, the specimens were finished with 600 grit SIC paper and polished with Twist DIA (Kuraray, Japan) followed with 3, 1 and 0.5 µm grit diamond pastes (Shofu; Japan, Diamond polish Ultradent; USA). Then, each composite group was randomly divided into four subgroups according to the discoloring agents; Black tea, coffee, red wine, and artificial saliva (n=10) and initial color measurements (spectrophotometer; Minolta CM-2600d) and initial Ra (profilometer; Perthometer M1 Mahr, Germany) were evaluated. The immersion protocol in discoloring agents was repeated for 21 days. Color measurements were performed after 7, 14, and 21 days, and ∆E 00 was calculated, while Ra was evaluated after 21 days. Representative specimens from each group were investigated under SEM (Tübitak MAM). ∆E 00 and Ra data were analyzed using three-way ANOVA and post hoc Tukey's tests (p<0.05). Results: ∆E 00 and Ra were significantly influenced by the composite (p<0.001), discoloring agent (p<0.001), and the evaluation period (p<0.001), while significant interactions were evaluated between the variables for both test methods. For all the composites and evaluation periods, red wine resulted significantly in the highest color change (p<0.001), which was followed by black tea (p<0.001) and coffee (p<0.001). After 21 days, GI and FU resulted significantly in the lowest ∆E 00 among all the tested universal composites for red wine (13.131±0.663; 12.89±0.97 respectively) and black tea (9.47±1.15; 10.534±0.349 respectively). All the composites revealed significantly higher Ra after exposure to discoloring agents (p<0.001), however, no significant differences were evaluated among red wine, black tea and coffee except UF and EA (p>0.05). Conclusion: Universal composites revealed unacceptable color change and increased surface roughness after exposure to discoloring agents over a period of 21 days, however the increase in surface roughness did not reach the critical threshold value for plaque accumulation. Key Words: color stability, surface roughness, universal composites, injectable composite.